time travel possible yet

Is Time Travel Possible?

We all travel in time! We travel one year in time between birthdays, for example. And we are all traveling in time at approximately the same speed: 1 second per second.

We typically experience time at one second per second. Credit: NASA/JPL-Caltech

NASA's space telescopes also give us a way to look back in time. Telescopes help us see stars and galaxies that are very far away . It takes a long time for the light from faraway galaxies to reach us. So, when we look into the sky with a telescope, we are seeing what those stars and galaxies looked like a very long time ago.

However, when we think of the phrase "time travel," we are usually thinking of traveling faster than 1 second per second. That kind of time travel sounds like something you'd only see in movies or science fiction books. Could it be real? Science says yes!

This image from the Hubble Space Telescope shows galaxies that are very far away as they existed a very long time ago. Credit: NASA, ESA and R. Thompson (Univ. Arizona)

How do we know that time travel is possible?

More than 100 years ago, a famous scientist named Albert Einstein came up with an idea about how time works. He called it relativity. This theory says that time and space are linked together. Einstein also said our universe has a speed limit: nothing can travel faster than the speed of light (186,000 miles per second).

Einstein's theory of relativity says that space and time are linked together. Credit: NASA/JPL-Caltech

What does this mean for time travel? Well, according to this theory, the faster you travel, the slower you experience time. Scientists have done some experiments to show that this is true.

For example, there was an experiment that used two clocks set to the exact same time. One clock stayed on Earth, while the other flew in an airplane (going in the same direction Earth rotates).

After the airplane flew around the world, scientists compared the two clocks. The clock on the fast-moving airplane was slightly behind the clock on the ground. So, the clock on the airplane was traveling slightly slower in time than 1 second per second.

Credit: NASA/JPL-Caltech

Can we use time travel in everyday life?

We can't use a time machine to travel hundreds of years into the past or future. That kind of time travel only happens in books and movies. But the math of time travel does affect the things we use every day.

For example, we use GPS satellites to help us figure out how to get to new places. (Check out our video about how GPS satellites work .) NASA scientists also use a high-accuracy version of GPS to keep track of where satellites are in space. But did you know that GPS relies on time-travel calculations to help you get around town?

GPS satellites orbit around Earth very quickly at about 8,700 miles (14,000 kilometers) per hour. This slows down GPS satellite clocks by a small fraction of a second (similar to the airplane example above).

GPS satellites orbit around Earth at about 8,700 miles (14,000 kilometers) per hour. Credit: GPS.gov

However, the satellites are also orbiting Earth about 12,550 miles (20,200 km) above the surface. This actually speeds up GPS satellite clocks by a slighter larger fraction of a second.

Here's how: Einstein's theory also says that gravity curves space and time, causing the passage of time to slow down. High up where the satellites orbit, Earth's gravity is much weaker. This causes the clocks on GPS satellites to run faster than clocks on the ground.

The combined result is that the clocks on GPS satellites experience time at a rate slightly faster than 1 second per second. Luckily, scientists can use math to correct these differences in time.

If scientists didn't correct the GPS clocks, there would be big problems. GPS satellites wouldn't be able to correctly calculate their position or yours. The errors would add up to a few miles each day, which is a big deal. GPS maps might think your home is nowhere near where it actually is!

In Summary:

Yes, time travel is indeed a real thing. But it's not quite what you've probably seen in the movies. Under certain conditions, it is possible to experience time passing at a different rate than 1 second per second. And there are important reasons why we need to understand this real-world form of time travel.

If you liked this, you may like:

Is time travel possible? Why one scientist says we 'cannot ignore the possibility.'

A common theme in science-fiction media , time travel is captivating. It’s defined by the late philosopher David Lewis in his essay “The Paradoxes of Time Travel” as “[involving] a discrepancy between time and space time. Any traveler departs and then arrives at his destination; the time elapsed from departure to arrival … is the duration of the journey.”

Time travel is usually understood by most as going back to a bygone era or jumping forward to a point far in the future . But how much of the idea is based in reality? Is it possible to travel through time? 

Is time travel possible?

According to NASA, time travel is possible , just not in the way you might expect. Albert Einstein’s theory of relativity says time and motion are relative to each other, and nothing can go faster than the speed of light , which is 186,000 miles per second. Time travel happens through what’s called “time dilation.”

Time dilation , according to Live Science, is how one’s perception of time is different to another's, depending on their motion or where they are. Hence, time being relative. 

Learn more: Best travel insurance

Dr. Ana Alonso-Serrano, a postdoctoral researcher at the Max Planck Institute for Gravitational Physics in Germany, explained the possibility of time travel and how researchers test theories. 

Space and time are not absolute values, Alonso-Serrano said. And what makes this all more complex is that you are able to carve space-time .

“In the moment that you carve the space-time, you can play with that curvature to make the time come in a circle and make a time machine,” Alonso-Serrano told USA TODAY. 

She explained how, theoretically, time travel is possible. The mathematics behind creating curvature of space-time are solid, but trying to re-create the strict physical conditions needed to prove these theories can be challenging. 

“The tricky point of that is if you can find a physical, realistic, way to do it,” she said. 

Alonso-Serrano said wormholes and warp drives are tools that are used to create this curvature. The matter needed to achieve curving space-time via a wormhole is exotic matter , which hasn’t been done successfully. Researchers don’t even know if this type of matter exists, she said.

“It's something that we work on because it's theoretically possible, and because it's a very nice way to test our theory, to look for possible paradoxes,” Alonso-Serrano added.

“I could not say that nothing is possible, but I cannot ignore the possibility,” she said. 

She also mentioned the anecdote of  Stephen Hawking’s Champagne party for time travelers . Hawking had a GPS-specific location for the party. He didn’t send out invites until the party had already happened, so only people who could travel to the past would be able to attend. No one showed up, and Hawking referred to this event as "experimental evidence" that time travel wasn't possible.

What did Albert Einstein invent?: Discoveries that changed the world

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April 26, 2023

Is Time Travel Possible?

The laws of physics allow time travel. So why haven’t people become chronological hoppers?

By Sarah Scoles

yuanyuan yan/Getty Images

In the movies, time travelers typically step inside a machine and—poof—disappear. They then reappear instantaneously among cowboys, knights or dinosaurs. What these films show is basically time teleportation .

Scientists don’t think this conception is likely in the real world, but they also don’t relegate time travel to the crackpot realm. In fact, the laws of physics might allow chronological hopping, but the devil is in the details.

Time traveling to the near future is easy: you’re doing it right now at a rate of one second per second, and physicists say that rate can change. According to Einstein’s special theory of relativity, time’s flow depends on how fast you’re moving. The quicker you travel, the slower seconds pass. And according to Einstein’s general theory of relativity , gravity also affects clocks: the more forceful the gravity nearby, the slower time goes.

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“Near massive bodies—near the surface of neutron stars or even at the surface of the Earth, although it’s a tiny effect—time runs slower than it does far away,” says Dave Goldberg, a cosmologist at Drexel University.

If a person were to hang out near the edge of a black hole , where gravity is prodigious, Goldberg says, only a few hours might pass for them while 1,000 years went by for someone on Earth. If the person who was near the black hole returned to this planet, they would have effectively traveled to the future. “That is a real effect,” he says. “That is completely uncontroversial.”

Going backward in time gets thorny, though (thornier than getting ripped to shreds inside a black hole). Scientists have come up with a few ways it might be possible, and they have been aware of time travel paradoxes in general relativity for decades. Fabio Costa, a physicist at the Nordic Institute for Theoretical Physics, notes that an early solution with time travel began with a scenario written in the 1920s. That idea involved massive long cylinder that spun fast in the manner of straw rolled between your palms and that twisted spacetime along with it. The understanding that this object could act as a time machine allowing one to travel to the past only happened in the 1970s, a few decades after scientists had discovered a phenomenon called “closed timelike curves.”

“A closed timelike curve describes the trajectory of a hypothetical observer that, while always traveling forward in time from their own perspective, at some point finds themselves at the same place and time where they started, creating a loop,” Costa says. “This is possible in a region of spacetime that, warped by gravity, loops into itself.”

“Einstein read [about closed timelike curves] and was very disturbed by this idea,” he adds. The phenomenon nevertheless spurred later research.

Science began to take time travel seriously in the 1980s. In 1990, for instance, Russian physicist Igor Novikov and American physicist Kip Thorne collaborated on a research paper about closed time-like curves. “They started to study not only how one could try to build a time machine but also how it would work,” Costa says.

Just as importantly, though, they investigated the problems with time travel. What if, for instance, you tossed a billiard ball into a time machine, and it traveled to the past and then collided with its past self in a way that meant its present self could never enter the time machine? “That looks like a paradox,” Costa says.

Since the 1990s, he says, there’s been on-and-off interest in the topic yet no big breakthrough. The field isn’t very active today, in part because every proposed model of a time machine has problems. “It has some attractive features, possibly some potential, but then when one starts to sort of unravel the details, there ends up being some kind of a roadblock,” says Gaurav Khanna of the University of Rhode Island.

For instance, most time travel models require negative mass —and hence negative energy because, as Albert Einstein revealed when he discovered E = mc 2 , mass and energy are one and the same. In theory, at least, just as an electric charge can be positive or negative, so can mass—though no one’s ever found an example of negative mass. Why does time travel depend on such exotic matter? In many cases, it is needed to hold open a wormhole—a tunnel in spacetime predicted by general relativity that connects one point in the cosmos to another.

Without negative mass, gravity would cause this tunnel to collapse. “You can think of it as counteracting the positive mass or energy that wants to traverse the wormhole,” Goldberg says.

Khanna and Goldberg concur that it’s unlikely matter with negative mass even exists, although Khanna notes that some quantum phenomena show promise, for instance, for negative energy on very small scales. But that would be “nowhere close to the scale that would be needed” for a realistic time machine, he says.

These challenges explain why Khanna initially discouraged Caroline Mallary, then his graduate student at the University of Massachusetts Dartmouth, from doing a time travel project. Mallary and Khanna went forward anyway and came up with a theoretical time machine that didn’t require negative mass. In its simplistic form, Mallary’s idea involves two parallel cars, each made of regular matter. If you leave one parked and zoom the other with extreme acceleration, a closed timelike curve will form between them.

Easy, right? But while Mallary’s model gets rid of the need for negative matter, it adds another hurdle: it requires infinite density inside the cars for them to affect spacetime in a way that would be useful for time travel. Infinite density can be found inside a black hole, where gravity is so intense that it squishes matter into a mind-bogglingly small space called a singularity. In the model, each of the cars needs to contain such a singularity. “One of the reasons that there's not a lot of active research on this sort of thing is because of these constraints,” Mallary says.

Other researchers have created models of time travel that involve a wormhole, or a tunnel in spacetime from one point in the cosmos to another. “It's sort of a shortcut through the universe,” Goldberg says. Imagine accelerating one end of the wormhole to near the speed of light and then sending it back to where it came from. “Those two sides are no longer synced,” he says. “One is in the past; one is in the future.” Walk between them, and you’re time traveling.

You could accomplish something similar by moving one end of the wormhole near a big gravitational field—such as a black hole—while keeping the other end near a smaller gravitational force. In that way, time would slow down on the big gravity side, essentially allowing a particle or some other chunk of mass to reside in the past relative to the other side of the wormhole.

Making a wormhole requires pesky negative mass and energy, however. A wormhole created from normal mass would collapse because of gravity. “Most designs tend to have some similar sorts of issues,” Goldberg says. They’re theoretically possible, but there’s currently no feasible way to make them, kind of like a good-tasting pizza with no calories.

And maybe the problem is not just that we don’t know how to make time travel machines but also that it’s not possible to do so except on microscopic scales—a belief held by the late physicist Stephen Hawking. He proposed the chronology protection conjecture: The universe doesn’t allow time travel because it doesn’t allow alterations to the past. “It seems there is a chronology protection agency, which prevents the appearance of closed timelike curves and so makes the universe safe for historians,” Hawking wrote in a 1992 paper in Physical Review D .

Part of his reasoning involved the paradoxes time travel would create such as the aforementioned situation with a billiard ball and its more famous counterpart, the grandfather paradox : If you go back in time and kill your grandfather before he has children, you can’t be born, and therefore you can’t time travel, and therefore you couldn’t have killed your grandfather. And yet there you are.

Those complications are what interests Massachusetts Institute of Technology philosopher Agustin Rayo, however, because the paradoxes don’t just call causality and chronology into question. They also make free will seem suspect. If physics says you can go back in time, then why can’t you kill your grandfather? “What stops you?” he says. Are you not free?

Rayo suspects that time travel is consistent with free will, though. “What’s past is past,” he says. “So if, in fact, my grandfather survived long enough to have children, traveling back in time isn’t going to change that. Why will I fail if I try? I don’t know because I don’t have enough information about the past. What I do know is that I’ll fail somehow.”

If you went to kill your grandfather, in other words, you’d perhaps slip on a banana en route or miss the bus. “It's not like you would find some special force compelling you not to do it,” Costa says. “You would fail to do it for perfectly mundane reasons.”

In 2020 Costa worked with Germain Tobar, then his undergraduate student at the University of Queensland in Australia, on the math that would underlie a similar idea: that time travel is possible without paradoxes and with freedom of choice.

Goldberg agrees with them in a way. “I definitely fall into the category of [thinking that] if there is time travel, it will be constructed in such a way that it produces one self-consistent view of history,” he says. “Because that seems to be the way that all the rest of our physical laws are constructed.”

No one knows what the future of time travel to the past will hold. And so far, no time travelers have come to tell us about it.

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Is time travel possible? An astrophysicist explains

Will it ever be possible for time travel to occur? – Alana C., age 12, Queens, New York

Have you ever dreamed of traveling through time, like characters do in science fiction movies? For centuries, the concept of time travel has captivated people’s imaginations. Time travel is the concept of moving between different points in time, just like you move between different places. In movies, you might have seen characters using special machines, magical devices or even hopping into a futuristic car to travel backward or forward in time.

But is this just a fun idea for movies, or could it really happen?

The question of whether time is reversible remains one of the biggest unresolved questions in science. If the universe follows the  laws of thermodynamics , it may not be possible. The second law of thermodynamics states that things in the universe can either remain the same or become more disordered over time.

It’s a bit like saying you can’t unscramble eggs once they’ve been cooked. According to this law, the universe can never go back exactly to how it was before. Time can only go forward, like a one-way street.

Time is relative

However, physicist Albert Einstein’s  theory of special relativity  suggests that time passes at different rates for different people. Someone speeding along on a spaceship moving close to the  speed of light  – 671 million miles per hour! – will experience time slower than a person on Earth.

Related: The speed of light, explained

People have yet to build spaceships that can move at speeds anywhere near as fast as light, but astronauts who visit the International Space Station orbit around the Earth at speeds close to 17,500 mph. Astronaut Scott Kelly has spent 520 days at the International Space Station, and as a result has aged a little more slowly than his twin brother – and fellow astronaut – Mark Kelly. Scott used to be 6 minutes younger than his twin brother. Now, because Scott was traveling so much faster than Mark and for so many days, he is  6 minutes and 5 milliseconds younger .

Some scientists are exploring other ideas that could theoretically allow time travel. One concept involves  wormholes , or hypothetical tunnels in space that could create shortcuts for journeys across the universe. If someone could build a wormhole and then figure out a way to move one end at close to the speed of light – like the hypothetical spaceship mentioned above – the moving end would age more slowly than the stationary end. Someone who entered the moving end and exited the wormhole through the stationary end would come out in their past.

However, wormholes remain theoretical : Scientists have yet to spot one. It also looks like it would be  incredibly challenging  to send humans through a wormhole space tunnel.

Time travel paradoxes and failed dinner parties

There are also paradoxes associated with time travel. The famous “ grandfather paradox ” is a hypothetical problem that could arise if someone traveled back in time and accidentally prevented their grandparents from meeting. This would create a paradox where you were never born, which raises the question: How could you have traveled back in time in the first place? It’s a mind-boggling puzzle that adds to the mystery of time travel.

Famously, physicist Stephen Hawking tested the possibility of time travel by  throwing a dinner party  where invitations noting the date, time and coordinates were not sent out until after it had happened. His hope was that his invitation would be read by someone living in the future, who had capabilities to travel back in time. But no one showed up.

As he  pointed out : “The best evidence we have that time travel is not possible, and never will be, is that we have not been invaded by hordes of tourists from the future.”

Telescopes are time machines

Interestingly, astrophysicists armed with powerful telescopes possess a unique form of time travel. As they peer into the vast expanse of the cosmos, they gaze into the past universe. Light from all galaxies and stars takes time to travel, and these beams of light carry information from the distant past. When astrophysicists observe a star or a galaxy through a telescope, they are not seeing it as it is in the present, but as it existed when the light began its journey to Earth millions to billions of years ago.

NASA’s newest space telescope, the  James Webb Space Telescope , is peering at galaxies that were formed at the very beginning of the Big Bang, about 13.7 billion years ago.

While we aren’t likely to have time machines like the ones in movies anytime soon, scientists are actively researching and exploring new ideas. But for now, we’ll have to enjoy the idea of time travel in our favorite books, movies and dreams.

This article first appeared on the Conversation. You can read the original here .

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Time travel is theoretically possible, calculations show. But that doesn't mean you could change the past.

• Time travel is possible based on the laws of physics, according to researchers.
• But time-travelers wouldn't be able to alter the past in a measurable way, they say. 
• And the future would essentially stay the same, according to the reseachers. 

Imagine you could hop into a time machine, press a button, and journey back to 2019, before the novel coronavirus made the leap from animals to humans.  

What if you could find and isolate patient zero? Theoretically, the COVID-19 pandemic wouldn't happen, right? 

Not quite, because then future-you wouldn't have decided to time travel in the first place.

For decades, physicists have been studying and debating versions of this paradox: If we could travel back in time and change the past, what would happen to the future?

A 2020 study offered a potential answer: Nothing.

"Events readjust around anything that could cause a paradox, so the paradox does not happen," Germain Tobar, the study's author previously told IFLScience .

Tobar's work, published in the peer-reviewed journal Classical and Quantum Gravity in September 2020, suggests that according to the rules of theoretical physics, anything you tried to change in the past would be corrected by subsequent events.

Put simply: It's theoretically possible to go back in time, but you couldn't change history.

The grandfather paradox

Physicists have considered time travel to be theoretically possible since Albert Einstein came up with his theory of relativity. Einstein's calculations suggest it's possible for an object in our universe to travel through space and time in a circular direction, eventually ending up at a point on its journey where it's been before – a path called a closed time-like curve.

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Still, physicists continue to struggle with scenarios like the coronavirus example above, in which time-travelers alter events that already happened. The most famous example is known as the grandfather paradox: Say a time-traveler goes back to the past and kills a younger version of his or her grandfather. The grandfather then wouldn't have any children, erasing the time-traveler's parents and, of course, the time-traveler, too. But then who would kill Grandpa?

A take on this paradox appears in the movie "Back to the Future," when Marty McFly almost stops his parents from meeting in the past – potentially causing himself to disappear. 

To address the paradox, Tobar and his supervisor, Dr. Fabio Costa, used the "billiard-ball model," which imagines cause and effect as a series of colliding billiard balls, and a circular pool table as a closed time-like curve.

Imagine a bunch of billiard balls laid out across that circular table. If you push one ball from position X, it bangs around the table, hitting others in a particular pattern. 

The researchers calculated that even if you mess with the ball's pattern at some point in its journey, future interactions with other balls can correct its path, leading it to come back to the same position and speed that it would have had you not interfered.

"Regardless of the choice, the ball will fall into the same place," Dr Yasunori Nomura, a theoretical physicist at UC Berkeley, previously told Insider.

Tobar's model, in other words, says you could travel back in time, but you couldn't change how events unfolded significantly enough to alter the future, Nomura said. Applied to the grandfather paradox, then, this would mean that something would always get in the way of your attempt to kill your grandfather. Or at least by the time he did die, your grandmother would already be pregnant with your mother. 

Back to the coronavirus example. Let's say you were to travel back to 2019 and intervene in patient zero's life. According to Tobar's line of thinking, the pandemic would still happen somehow.

"You might try and stop patient zero from becoming infected, but in doing so you would catch the virus and become patient zero, or someone else would," Tobar said, according to Australia's University of Queensland , where Tobar graduated from. 

Nomura said that although the model is too simple to represent the full range of cause and effect in our universe, it's a good starting point for future physicists.  

Watch: There are 2 types of time travel and physicists agree that one of them is possible

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Is time travel even possible? An astrophysicist explains the science behind the science fiction

Assistant Professor of Astronomy and Astrophysics, University of Maryland, Baltimore County

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Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to [email protected] .

Will it ever be possible for time travel to occur? – Alana C., age 12, Queens, New York

Have you ever dreamed of traveling through time, like characters do in science fiction movies? For centuries, the concept of time travel has captivated people’s imaginations. Time travel is the concept of moving between different points in time, just like you move between different places. In movies, you might have seen characters using special machines, magical devices or even hopping into a futuristic car to travel backward or forward in time.

But is this just a fun idea for movies, or could it really happen?

The question of whether time is reversible remains one of the biggest unresolved questions in science. If the universe follows the laws of thermodynamics , it may not be possible. The second law of thermodynamics states that things in the universe can either remain the same or become more disordered over time.

It’s a bit like saying you can’t unscramble eggs once they’ve been cooked. According to this law, the universe can never go back exactly to how it was before. Time can only go forward, like a one-way street.

Time is relative

However, physicist Albert Einstein’s theory of special relativity suggests that time passes at different rates for different people. Someone speeding along on a spaceship moving close to the speed of light – 671 million miles per hour! – will experience time slower than a person on Earth.

People have yet to build spaceships that can move at speeds anywhere near as fast as light, but astronauts who visit the International Space Station orbit around the Earth at speeds close to 17,500 mph. Astronaut Scott Kelly has spent 520 days at the International Space Station, and as a result has aged a little more slowly than his twin brother – and fellow astronaut – Mark Kelly. Scott used to be 6 minutes younger than his twin brother. Now, because Scott was traveling so much faster than Mark and for so many days, he is 6 minutes and 5 milliseconds younger .

Some scientists are exploring other ideas that could theoretically allow time travel. One concept involves wormholes , or hypothetical tunnels in space that could create shortcuts for journeys across the universe. If someone could build a wormhole and then figure out a way to move one end at close to the speed of light – like the hypothetical spaceship mentioned above – the moving end would age more slowly than the stationary end. Someone who entered the moving end and exited the wormhole through the stationary end would come out in their past.

However, wormholes remain theoretical: Scientists have yet to spot one. It also looks like it would be incredibly challenging to send humans through a wormhole space tunnel.

Paradoxes and failed dinner parties

There are also paradoxes associated with time travel. The famous “ grandfather paradox ” is a hypothetical problem that could arise if someone traveled back in time and accidentally prevented their grandparents from meeting. This would create a paradox where you were never born, which raises the question: How could you have traveled back in time in the first place? It’s a mind-boggling puzzle that adds to the mystery of time travel.

Famously, physicist Stephen Hawking tested the possibility of time travel by throwing a dinner party where invitations noting the date, time and coordinates were not sent out until after it had happened. His hope was that his invitation would be read by someone living in the future, who had capabilities to travel back in time. But no one showed up.

As he pointed out : “The best evidence we have that time travel is not possible, and never will be, is that we have not been invaded by hordes of tourists from the future.”

Telescopes are time machines

Interestingly, astrophysicists armed with powerful telescopes possess a unique form of time travel. As they peer into the vast expanse of the cosmos, they gaze into the past universe. Light from all galaxies and stars takes time to travel, and these beams of light carry information from the distant past. When astrophysicists observe a star or a galaxy through a telescope, they are not seeing it as it is in the present, but as it existed when the light began its journey to Earth millions to billions of years ago.

NASA’s newest space telescope, the James Webb Space Telescope , is peering at galaxies that were formed at the very beginning of the Big Bang, about 13.7 billion years ago.

While we aren’t likely to have time machines like the ones in movies anytime soon, scientists are actively researching and exploring new ideas. But for now, we’ll have to enjoy the idea of time travel in our favorite books, movies and dreams.

Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to [email protected] . Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.

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• Stephen Hawking
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Time travel is possible, but it’s a one-way ticket

Chenoa van den Boogaard , Physics and Astronomy editor

The ability to travel through time, whether it is to fix a mistake in the past or gain insight into the future, has long been embraced by science fiction and debated by theoretical physicists. While the debate continues over whether travelling into the past is possible, physicists have determined that travelling to the future most certainly is. And you don’t need a wormhole or a DeLorean to do it.

Real-life time travel occurs through time dilation, a property of Einstein’s special relativity . Einstein was the first to realize that time is not constant, as previously believed, but instead slows down as you move faster through space.

As part of his theory, Einstein re-envisioned space itself. He coined the phrase “spacetime,” fusing the three dimensions of space and one dimension of time into a single term. Instead of treating space as a flat and rigid place that holds all the objects in the universe, Einstein thought of it as curved and malleable, able to form gravitational dips around masses that pull other objects in, just as a bowling ball placed in the centre of a trampoline would cause any smaller object placed on the trampoline to slide towards the centre.

A computer-generated representation of Einstein’s curved spacetime. The Earth creates a gravitational dip in the fabric of spacetime which is deepest at its core. Courtesy and © of NASA

The closer an object gets to the centre of the dip, the faster it accelerates. The centre of the Earth’s gravitational dip is located at the Earth’s core, where gravitational acceleration is strongest. According to Einstein’s theory, because time moves more slowly as you move faster through space, the closer an object is to the centre of the Earth, the slower time moves for that object.

This effect can be seen in GPS satellites, which orbit 20,200 kilometres above the Earth’s surface. These satellites have highly precise clocks onboard that gain an average of 38 microseconds per day due to time dilation. While this time gain seems insignificant, GPS satellites rely on their onboard clocks to maintain precise global positioning. Running 38 microseconds fast would result in a positioning error of nearly 10 kilometres, an error that would increase daily if the time difference were not constantly corrected.

A more dramatic example of time dilation can be seen in the movie Interstellar when Matthew McConaughey and his crew land on a planet with an extreme gravitational field caused by a nearby black hole. Because of the black hole’s intense gravitational influence, time slows dramatically for the crew on the planet, making one hour on the surface equal to seven years on Earth. This is why, when the crew returns to Earth, Matthew McConaughey’s daughter is an old woman while he appears to be the same age as when he left.

So why hasn’t humanity succeeded in making such drastic leaps forward in time? The answer to this question comes down to velocity. In order for humanity to send a traveller years into the future, we would either have to take advantage of the intense gravitational acceleration caused by black holes or send the traveller rocketing into space at close to the speed of light (about 1 billion km/h). With our current technology , jumping a few microseconds into the future is all humans can manage.

But if technology one day allows us to send a human into the future by travelling close to the speed of light, would there be any way for the traveller to use time dilation to return to the past and report her findings? “Interstellar travel reaching close to the speed of light might be possible,” says Dr. Jaymie Matthews , professor of astrophysics at the University of British Columbia, “[but] this voyage is one way into the future, not back to the past.”

If we can’t use time dilation to return to the past, does this mean that the past is forever inaccessible? Perhaps not. Einstein proposed that time travel into the past could be achieved through an Einstein-Rosen bridge, a type of wormhole. Wormholes are theoretical areas of spacetime that are warped in a way that connects two distant points in space.

A visualization of a wormhole: The fabric of spacetime curves back upon itself, forming a bridge between two distant locations. Image by Panzi , CC-BY 3.0

Einstein’s equations suggested that this bridge in space could hypothetically connect two points in time instead if it were stable enough. “At the moment, even an Einstein-Rosen bridge cannot [be used to] go back in the past because it doesn’t live long enough – it is not stable,” Matthews explains.

“Even if it was stable, it [requires] other physics, which we don’t have. Hypothetical particles and states of matter that have “exotic” physical properties that would violate known laws of physics, such as a particle having a negative mass. That is why “wormholes” are only science fiction.”

While it would be fascinating to travel back in time to see the dinosaurs or to meet Albert Einstein and show him the reality of time travel, perhaps it is best if the past remains untouched. Travelling to the past invites the possibility of making an alteration that could destroy the future. For example, in Back to the Future , Marty McFly travels to the past and inadvertently prevents his parents from meeting each other, nearly preventing his own existence. But if he had undone his own existence, how could he have travelled back in time in the first place?

Marty’s adventures are a variation of the grandfather paradox: what happens if you go back in time and kill your grandfather before your father is conceived? If you are successful, how is it possible that you’re alive to kill your grandfather in the first place?

A recent study at the University of Queensland may have the answer to this baffling paradox. In this study, the researchers prove mathematically that paradox-free time travel is possible, showing that the universe will self-correct to avoid inconsistencies. If this is true, then even if we could travel back in time, we would never be able to alter events to create a different future.

While these new findings are enlightening, there appears to be more evidence that, although time dilation can allow us to glimpse the future, we will never be able to visit the past. As the late Stephen Hawking said in his book Black Holes and Baby Universes , “The best evidence we have that time travel [into the past] is not possible, and never will be, is that we have not been invaded by hordes of tourists from the future.”

Banner image by Alex Lehner, CC BY 2.0

240 thoughts on “ Time travel is possible, but it’s a one-way ticket ”

How do I go about time travel? what do I need how do I get those required things?

Very large ring magnets and some mathematics and will to see it in reality.

How about a sphere magnet ship…

hoe about 3d time and hemi synch or portals augmented reality,power of suggestion..drugs pcp binural tones frequency amplitude .virtual computing ie.

I’m a time traveling tourist, Stephen Hawking was wrong.

Time is simply a measurement of space under the amount given its mass and the amount of light and dark in which governs its mass in a 4dimensional reality step outside of the force in which permenates its flow one would reside there would be no past present or future there be a fixed permance of a constant here and now and so ok then what is to come.

Very well explained article !!

But I think if physics says time travel can be possible then it’s definitely possible. Considering not to go back to your childhood and fix things but rather can go to the past but as invisible person to them. So that,

No actions by you would impact your future.

Regards, Kirankumar DR

Tell me more

Yes.. I wish I can do this too 🙂

We will understand it better, by and by…

I have a theory for warp speed, but nasa would have to put it to the test…check my Facebook

I am reading for this drive , i am ready , without think my life safe or not

@Ravi chandila English translation please?

Please someone help me I just want to send a message to myself in my past.,to get the love of my life, he never revealed to me his feelings now my life is ruined by the decision of my elders Please help me, it’s question of my life and death. Nazneen

Is time travel machine is their, if the time travel machine is true can it move to the past . To bring back my lost life

That’s the problem you know.. it is not there that’s why we aren’t able to travel time..and yes it it will be built then you will be able to do so…..

damn my life is also lost and broken but still no one can give a time machine for free

DO NOT change the future. That’s why people like you couldn’t go. One wrong person to ruin it for the rest of us

On the point of time reversal, it is evidently impossible. The Uncertainty Principle prohibits spacetime reversal. The Universe is unable to remember its past (as a consequence of the Uncertainty Principle), therefore the Universe cannot reorganise itself.

Can I have to go on my past with another time travel it is a possible when just tell me about one thing that can I have to go in my past one year

we dont need magnets.we need a strong gravitational force to warp spacetime allowing us to travel through with speed of sound or speed of light or faster.we need to learn how to control such force carefully or it could be lethal.gravity slows down time.but it can theoratically work both ways.if we can reverse the gravity’s natural reaction we could speed up a spacecraft faster than light(its all relative(and theoratical))

I WAS ACTUALLY JUST THINKING THE SAME THINFG BEFORE READING YOUR PIECE. VERY WELL EXPLAINED, AND IT DOES MAKE ALOT OF SENSE. WELL DONE.

oh and I forgot to add it can be the key to look into the universe and also travelling time(theoratical).speed and gravity are the key to the universe(theory not proved)

All you really need is a crystal diode with 16 sides, a large pain of glass, and a frequency transmitter near a bathtub full of ice cold water….if you reach the right frequency you can travel through time forward and reverse…

Magnetized metal(VCR Reading Head), to read time out of the Magnetosphere all around earth. The Magnetosphere kills 2 birds with one stone- it protects earth and it records human time:

Mystery solved and I will explain, I was in a coma 3 months and I experienced things, I traveled time forward and backward, it is not a one way ticket. Movies and songs are recorded on magnetic tape in a VCR tape Cartridge or Cassette tape,   Magnetic tape recording works by converting electrical signals into magnetic energy, which imprints a record of the signal onto a moving tape covered in magnetic particles.   3D life on earth(a movie), and the Magnetosphere all around earth coming from the core of earth(MAGNETIC ACTIVITY) without Atom Made Tape, is like a movie on magnetic Atom made tape in a VCR tape cartridge. Revolution and Rotation is the motor(VCR).

This is why people have those freaky Deji’vu feelings like they have lived this before, BECAUSE YOU HAVE, and how people can be psychic, and how there is Prophecy in the Bible. When a person dies, their Spirit- MIND(Thoughts, Feelings, Urges(Physical and mental personality)) breaks out of human body- a stopped heart is what releases the spirit from the human body. Then the Soul(Life) with the memory of your existence in it breaks out of spirit and goes back to your birthday with a erased memory, meanwhile your spirit goes back in time to when you were a teenager starting the mental puberty, maturity from that adult spirit you died with in last life.In that old movie Star Wars or maybe it was the Empire Strikes Back, there is a scene where Princess Laya plays like a 3D movie, that is EXACTLY how its of life on earth.

Mr Snow, I believe you as I have seen it too. As humans we have deep knowledge of things we cannot rationally explain but you have done a great job here.

I thought that Analogy would be a better and easier way to explain, or in a picture of the earth from far out in space with the atmosphere around it looks like a DVD disk and the earth being the center sticker but is in 3D.

Actually you are on to several things here. I have also had the infusion of knowledge that also had to do with comparing life to recorded movies and music. I know you were using it to explain your theory, but I do think there is something there, I always have. When you watch a movie you are seeing the past. Why can’t you somehow use a recording as a base to go back into? I agree with everything you said here, and it’s worth looking into.

Jeffrey, very interesting idea!! Could be something to that. As far as your coma experiences, I think there are things we just do not understand and are nearly impossible to explain. Perhaps time IS like a video tape, or a DVD? Magnetism is one of the forces of nature. I too have had some odd experiences that suggest that we are able to perceive things beyond our five known senses.

I think if you have had a near death experience, such as being in a coma, then you have experienced the powerful hallucinations provided by the chemical substance DMT which your body creates naturally in times of extreme trauma, but also found in most plants and used recreationally by some who are brave enough and into that kind of thing. Your theory is interesting, but completely unproven and as far as I know untested. If things were so simple, I’m sure many scientists would have already thought of such an idea and tested it.

How do I travel through time

Be alive and live life to the fullest is the best way to travel through time ! OR Befriend grey aliens../ They may hold the key to the sum of all knowledge in the universe..

Sounds good will it work

Really log vaps mil sakte hau h kya

Can you plz explain I didn’t get it

You dont first all you are not experienced in the field of the space time continum and you could you upset the already fragile and multitude of alternate realitys that have looping due irresponsible ones who somehow gotten the technology causing another altered time frame there are a disarray multiple reality which are looping in earths 4dimensonal time frame time traveling is not for a vacation or just to get a joy ride its a serious and complex reality not be joked about it is a real thing and certain individual have are upset the balance of earths original time zone note now the gaurdians of this region of milky way the galatic order of the light keepers Angelic gaurdians of the (names with held)are working over time ooh nice pun (over TIME) ha wow to restore Earth back to a original time continum

Who said I want a joy ride, my life is devastated even my kids are suffering, I want to commit suicide but can’t leave my kids back, Being captive for most of my life, if my life is changed nothing will be disturbed, only thing happens is 3 life’s will be saved. And more so over I don’t want to travel I just want to send a message to myself in my past plz on the date of 30th May 1996. My life is ruined plz help me, it was my dad,brother, sister who pushed me into the dungeon and my husband and his family took over the charge of torturing me. Nazneen

I want to go back in time and tell my 5 year old self to burn the creepy dolls that my mom bought cause there is demons in it at the same time I will kidnap and torture my dad right now go back in time and show the younger version of my dad show him what will happen to his future self if he don’t get rid of those possessed objects and keeps letting my mom buy those antiques I’m 18 now I’m single no girlfriend no friend alone nothing very depressed too and I try to remember the positive things that happened in my life which there aren’t many tho but the demons keep squeezing my memory brain and my mom keeps on making so much loud noise including her damn mouth I have attempted to burn the demonic dolls but I only burned them for a minute or two with gas cause I was worried I might accidentally set my whole neighborhood on fire but then my mom threw it all in the recycle instead of the trash so the demons just keep bothering me its driving me nuts he he.

Access to a Quantum Computer Network on the web would be a good start. A series of ChatBots and webhook sites strategically placed in not only space, but in time. A series of algorithms and I think information can be transferred backwards to ones self…

How do we know that there are no horde of tourists among ourselves?

How do we know we’re all not tourists?

We’re all time travelers. We all travel into the future daily. 1 second at a time. Lol…

Agreed! I had the same thought!

Excellent question

If is possible, I would like to go back to: January the 1st 1975 & relive the 70’s as I prefer that decade to the awful one I am facing now, Back then We had more police our streets & left our front doors open, Those days were far much more better .

https://3netra.co.in/61-2/

Please do comment on my blog post regarding time travel

how about you ask the flash to help you

I need the time travel so I’m fails so many times i love time travel i have to go fast and future so i have no idea im travel is a my dream so my dream solution plz say me i have time travel so please help me someone please…..

I think you are over reacting

When we look at the stars now it is what they looked like years ago so what if we go to the stars and look down?

You cant go to the stars. It will just take billions and billions of years to go even to the next nearest star than our Sun- proxima centuri. Sorry to say, but do you think that you will be alive all those years??

You can do that without going to the stars… our planet reflects light as well thus making it visible from other parts of the universe…. has the word “reflection” crossed your mind ? 😉

Contact me on my hangout I will help you [email protected]

bro just time travel its not that hard

Please help me to time travel, can I see myself when I go back in time like Harmaini sees herself in Harry potter?? Or can I send messages to myself I know the particular date when to send. It’s not the mistake I had done in my past but it was done by my father and brother who are safe, happy enjoying their lives,my life is totally ruined Please help me. Nazneen

I want to go back in time to save my wife .it was a bad mastake she died .that could be changed i need to go back and save her. Please help me.yours gordon sutcliffe

Would love to hear more how it’s possible, as I am really so desperate to go back in time. I lost my wife 6mons back because of COVID and I will do the impossible things to make it happen.

DMT Experience

what is that?

Dmt experience. Time travel, out of body and sometimes superhuman capabilities.

Jump into a black hole

We have to lose something(the past) to gain something(the future) in time travel.Time cannot be played with.Am I correct.

you need to have d e t e r m i n a t i o n

Time machine is possible

speeder than light LOL

speeder than light cuz if the light break it limits it will move backward in time

Don’t Just don’t disturb the past

I want to go back in time and see my dad. I miss him.

mee too raina I lost my father the day before you posted the comment 18th may, crap it hurts me so much. I would rather die to bring those moments back….

Everything is connected . Time isn’t real .

It is universe we travel to and not a time line in one universe

Ask trump….Mandela effect…. dmt 5th dimension

u need an X-WING starfighter and a lightsaber to fight the knights at past and a R2-B2 to track

The fact that no one has time travelled to the past is the proof that time travelling will NEVER exist.

Others have. Portals open most of the time. Example: Miami Fl. Magnetic Material gets bombarded by the sun. Which fractures and formed portals within that area. Ley lines can lead to the portals of travel within miami for just to start. One can laugh or wonder if. In my experience jumping for the better the word of it (Movie Jumper) can be done. You can either Teleport or Time Travel. Our sun open these portals everyday. The best time when Sun spots start to emerge. All that electrons traveling at light speed is enough to rupture our magnetic fields on Earth. You will return of course. Like water on a lake or an ocean time will corrects itself. Your inner clock is your ticket back home. With a little math,fourth dimensional thinking,a magnetic meter, the right location,history research and luck. You may get to expirence it. First clue….cold spots…it may not be a ghost.

Plz can you help me please help me you can save my life

I wish I could help you, I can sense your sufferings.

You need a bag of hyperlink modules to start, then nuclear beepbeep gatangas, when you have that come back here and I will tell you what you need next.

You need high voltage beepbeep gatangas and a large broonasic magnet of about 450 Gauss, come back here when you have these and I will tell you the rest.

you need an old fashioned police box

If you rotate the center of the earth in the opposite direction, then the whole earth can be moved back in time, on the other hand, if you move the center of the earth and change its position by separating it from the part of the earth, then you will be able to time correctly. Let’s reach the other side.

How I could time travel any time travel machines inverted

give audition in the flash series..

I think that to go back in time you’d to travel faster than the speed of light since time stops at the speed of light but if you wanted to go back to say mlk’s assassination you would need to go at least 10 times the speed of light

You don’t want to, the moment you wrote that message is a historical point in time.

When time travel is possible, you should d̵͔̮͉̣̯̳͌i̩͒̍̆͟ͅs͎̲̖͙̺ͬ̽̊͆͢r̖̹͆͂̚͘ê̛̫̪̱͇̘̩ͬg̖͉̤͚ͭͣ̊̌͜a̯̗͚̬͍̱̦͑͂͒͡ṟ̝ͦ͗͘d͋҉̪̖̥͔̟̟͚̻ ͎̬ͧ̔́i̧͚̫̻̇ͮͫ̆t̩̻͉̩̘̰̠̫̓̂̕ ̦̻̳̦̉͆̊̇̀i̴̗͍̞͙͇ͣ̈́mͦ̑ͦ̚͏͚̜̬̹̘̟̭m̱͕̻͇̮̠̰̼ͫ̌͆͡e̢͈̜̱ͩd̵̦͙͔̭̹̃̿̈̚ͅi̛̖̬͓͚̩̝̗ͯa̦͎̭̣̭̘͔͙̅̏́ṯ̴̟ͥ̀͗e̵͎̭͓̟͗ͨ̂͒l̼͕͕ͦͦ͜y̸͙̯̺̘͉ͣ,͈̻͙̭̺̘̞̑ͫ͜ ͔̗̣͒͜d̶͇͚͉̦̞̗͛̍o̞̮̻̲̜̠̒ͩ̈́̀ͅ ̲̙̦̮̺̉́͂̏̀ṋ̞͖̌͠o̬͕̯̩͓̮̫̝͛ͩ̐͛͜t̼̙̿͊͆̕ ̲͚̲̬̦̗̐̀m̢̹̜̭̠̬͗̆ͣą̲̺̻͈̹͎̈́̇̉͛ǩ̜̪̱̀e̜̳͔͉̣͓̓͗͘ ̉҉̲̞̘͈ͅc̴̦̣̝͇͈̙̋ͥ́o̫͇͇̘̻̠̹͎ͯ̀n̺̹̣̦̔̇̾͢t͚̹͚̙̞̪̗̺̄͂͜a̞̗̖̻̩͉̋͛̆͘c͙̙̎͘t̻̠̣͉̹̠̣̲̐ͧͩ̈́̕ ̶͕̗̬̿w͓̞͍̹̰͖͉ͦ͐͡i͎̞̾ͦ̃̈́̕t̜̺̖̭̍ͦ͞h͙̰̬̖͎̰͛̇ͮͫ͡ ͣͯ͏͕̻͚̹̺ā̱̙̝̦̤̼̥͡n̶͔̜ͥ͆̌̋y̷͓̻̺̺͉͇̻ͨọ̱͙̜̈́̉ͣ̔͟ņ̦̟͔̜̫̗̒ͬe̡͕̮̓͂̚ ̡͓̘͚̭̹͔̉͐͋̽t̖͍͚̝̬͈̝͌͋͘ͅẖ̗̖͚̼͔͕͆̓̾͜a͈̣͍͕͍̋ͦͩͭ͢t̖̪̤̳͎̱̏͡ ̛̻̠̼̬̓ͫl̶̞̤̣͔̗͔̂ͅö̹̞̦̖͚̫̜̱́ͯ͠o̧̯̱̪̓ͮ̋k͉͎̝̻̓ͧ̕s̤͈̪̍͟ ̤̞̳͔̝̪̟̹̔̂ͨ͜h̛̝̲̰̻͗̅̏̃u̜̙͐̇̈͝m̧̞̮̟̦̳̟̊a̸͓̺̲̼̜͊͛̐n̶̳̮̒.͇̻͚͓̳̺̜̱͋ͬ͗ͩ͢

It’s Close I can feel it

Yes it becomes a history but my life also in the past changes and the present also with it. The way I’m suffering from the pain and want to end my life I’m 100% sure at least sure no one around me is or was as hopeless and horrible as my hubby I’m devastated I really want to send a message to my past it may not start but it will definitely change. I was forced, not given any option, my father and brother gave me wrong information and had no concerns for me. It was just survival for me. I repent for not killing myself when I had time, but now if I have a chance why not. Now when I’m out of my marriage I come to know a guy then had feelings for me, was madly in love and wanted to ask for my hand, now I want to inform my self and change everything plz help me.

I too would like to go back in time. I just wish he lived a happy eternal life. I would just like to repeat to come back in 2020.

I heard from a guy in Idaho that time travel is possible. You’ll need to go online and purchase a pogo stick looking device and make sure not to forget the crystals.

I think u need a black-hole-proof spaceship, go to the centre, escape the black hole and viola! You are now in the past. If you can’t escape, then you’d travel to a time where that black hole didn’t exist.

Believe me you time travel! If not physically then you do mentally,like you through dreams.

Though they sale it online, it would not take the chance. It is as simple as beating the speed of light and having some system to send you to the time you want. Time however is not real, and were just traving universes. It will all be in the open in 2028 according to other travelers.

All you need base on how to travel to time is very simple but had to find firstly find a way to get to space through a space rocket secondly find a very perfect consifigration for traveling to tiTme then find a very fast rocket that could create a form of force reaction in space in order yo enable fast speed in space for the break through of non gravity in space and make sure that while doing all you activities is not far away from planet and not also to close to planet earth and make sure that you are with wristwatchs whose time is set disame then you can to the future

Man you can get all you need for too build a time machine in your local store man, man I sure wished I’d kept mine but it frightened the heck off me man, sometimes when I fart I find a grape in my pants

time travel is a fake, baseless and delusional idea. If you believe in that crap then tell us if we are living in the future or in the past. To travel backward the entire system has to return all along with nature and events, it won’t be for you alone except time travel only happens in the mind.

you would need to get about 1,000,000 pounds of silicon and then somehow conduct enough energy to make 500 cars run without an engine and then go to a nuqular power plant and somehow make a portal. but the whole world could go out of orbit if you do that so I wouldent sugest it.

Time machine is good and bad because,with the time machine you will know about your future which is not good.

Is time travel actually a real thing because if it is then I need it because I am trying to go back in time to fix all of my mistakes

So what if time travel is the reason that we now believe there are other realities in our own world.this could be that a Time traveler we could only go back and couldn’t come back, and on doing so if you do something to change the past in stead make a new reality.making other things are deferent and ours realty stays the same . sometimes reality gets mixed up make the mandela effect that we see today

Time in the future it is faster then now. The past is slower so you can travel . It is up to you. One way is to meditate. You can travel and see any body you want right now. You can fly faster then light. That is one way. You go to the future. To go to the past you sleep for a long time. Some time you go to the future or the past. Your heart well stop and your body gets cold. Sometimes you can control it sometimes you can’t.

but how do we know that is really true ? i mean i want to figure this out, i want to time travel, but how is it that simple ? so many people have been trying to figure this out for many years and its that simple ?

Yeah what if you get stuck in there what do you do than

You cant go there in the first place. Dont worry. With current technology, we will only end up messing some few microseconds. Highly doubtful, if we can end up getting the news of travelling hundreds of years in our lifetime.

wait what would happen if someone saw you while you where in past/future i’m curious

Time is an illusion based on perceived reality and is only relative to our limitations. Time isn’t what it seems and all things can’t be figured out

Im on a school computer looking this up and i found this article and scrolling trough it and ive not heard one statement here as good as yours bro

This is blowing my mind people, then I see the school boy on the post. Great stuff, whoever reads this is already capable of travelling through time. Think about all people who have posted on this thread, now think about who will read mine. Now think of those €opposite trolls $ who never ever bother posting on you tube thread etc. But ONE comment from one of the time travellers who wrote on this thread. So that opposite troll is me,I don’t normally post.however because of previous comments I’m posting here. And I love the DMT shit I loved that and lived that one out in real life,,,,another day.

So my point is ifOne or two threads have made me write this….then what will my post make others write , think…..then I could travel back and not write this…. then what. Love the conception of time how can u travel something that doesn’t YOU perceive to be time, like a train can only run on its train tracks, a car can only drive on a road etc It’s posibble I know it is. Sometimes when u have fun times moves swift but locked in jail it goes snail pace. U c me. I write letters to myself from past from future. Remember everything that happens in present becomes part the past. But the future is what you hold in your hands. Question is, now you know….what the f are u gonna do about it?.. 01/04 ==== 21

Hahahah only realised school boy is named BIG dick pissing myself laughing I gotta go pee. Respect certified

so not halal mode

True so were not traveling in time. It is just different universe (on what we call) different time, day, tears, etc.

You would be scared for life

you will desepear

Maybe it has happened before and we just don’t know that they’re from the future. If people in the future time traveled, the would know that it’s dangerous to mess with the past and would pretend to be part of the past.

I believe time travel is already possible, however we cannot fix past mistakes without altering future predicaments. Say we stop JFK’s assasination, that would completely change the future from that point forward to one none of us can know/guess or conclude the effects? Other time travel purposes go to the future I think that from now our world will die off before 2096 basdd on overpopulation, global warming & polution as such creating islands of plastic waste in our oceans. The best thing my opinion go back to the garden of Eden, kill that Serpent Satan before he tricks Eve into the forbidden fruit. Then let God raise, enlighten & teach us how to be humanly sustainable on his planet & I guarantee technology & smart phones? Ain’t no part of it!!

Time travel possible but one n only theory of Stephen hawking

How it is possible to jump in time …??

Many ways. The most used is creating a black hole which can be done in a few ways. 1) traveling forwards or backwords faster than the speed of light 2) been known during heavy lightning strikes. Each way is a fast movement that opens the black hole. It has been done by the Government since the 1980s though they claimed they never beet the speed of light until 2002. However, Time is a illusion and their for we are actually traveling different universe that are differnt than ours even if the difference is by 1 thing. Each universe may have (what we call) different time, days and years. And each time we change that time line we created a new one. It is belief as CERN has said they destroy 5 universe, that they can travel to them. Since 2012 it has seem we been shifting and is now belief they have possibly came together. The event is known as The Mandela Effect.

No one has the right theory in my thinking. Only a few things are wrong. It is universes with (what we call) different time, days and years we are traveling to and not time itself as it is a illusion. Their is no stop to how much we can do, or where we can go. No limit as such say.

There is no God. No magical serpent or Garden of Eden ever existed. Basing a scientific theory on archaic stories does no one any good.

You choose a hopeless eternity. I choose hope through the promise of salvation through Christ for those who believe. You see, I have child in heaven. Thankfully, have a hopeful reality that I can embrace. There is a God. Our known universe is only 14 or so billion years old… is it mathematically possible that random molecules out of the Big Bang mixed in just the right way from to form a complex cellular organism… with DNA… and result in humans and such diversity of life forms? It’s naive to accept this as a result of chance. Think about it. How is that remotely possible without a creator?

Hahaha. You make it seem as tho the big bang happened, and we just popped into existence? Naw it’s called evolution baby, we started out as microscopic organisms, seriously, when did you drop out of school? But that’s like saying a some guy writes a book to explain away natural phenomenons that they were to stupid (un-evolved) to grasp and the concept good and bad and the eternal damnation, And thus, the Bible, and boom, everyone now was made by God, hahaha. When you can prove he/she exists, and that the Bible was a autobiography, and not just some twisted piece of Fiction, that has no real basis in reality, and cannot be proved to be more that a work of Fiction. Rather than being used as the16th Century control tact, ‘be good or you’ll go to hell’. But I guess that’s what they mean when they say ignorance is bliss, (maybe if I was as ignorant as y’all believers I’d believe to). But I can’t see how a ‘GOD’ would ever ask one of its creations to kill another.. Genocide, Crusades, all the ethnic cleansing.. All In the name of God Almighty! Hahahahahhaaa. Aliens are more believable than this shit, and theirs no proof they exist either. Hahahahaha. Fug’n Bible thumpers. ‘Step out side your faith and see the world for what it really is, a complex organism, mad of gravity and dust, quite a unique specimen! And we, yes Bible bangers, this includes you, are destroying it like the bubonic plague.’. ‘The end is coming and it’s our fault’

Have you taken the time to read The Old Testament and the prophecies therein that came to be ?.

How do you explain that ?.

My last post should read GS not G

You have not had an encounter yet with God. Don’t be so certain on yuour theory of evolution. He came and shook my reality to it’s core. Made thing possibly that no one could ever explain.

What are you talking about? Ur so wrong and funny in every way.

BlissfullyInformed just told me his comment was all an April fools prank. He believes in Jesus and was just fooling.

Time travel is very much possible just as you decided to come existence in this century meaning one can decide to be in another time zone . life is all about numbers, you just have to work on numbers

I’m pretty sure ppl don’t decide to come into existence. If that were true I wouldn’t be replying to your comment.

Un like your other reply, I understand what you mean. Each timeline (or universe as some see it) can easily be traveled to at will. No different than traveling threw your time you want to visit.

Science has proven a few things from the Bible is true. God does exist. Christians are confused with time and what it says. For a example. God created the world, as science even belives it was God who created the big bang, yet the bang has happen itself creating the moon, planets and stars. Christians also fail to understand chapter 1 and 2 of gen. spoke of two different creations which can be why we see dinosaurs before humans as chapter 1 spoke of animals first and humans 2nd. Their also was different time than, as without the moon a full day is 6 hours. It would take 4 days back than to equal are 1 day. Time is lost and Christians are just confuse on that time. That does not proof their is no God. As they have already found the robes of Jesus and remains of Noah’s ark, it proves much did happen. The bible only has less than 50% of what was written.

Changing the past is impossible, because if we went back into the past, that means we were already there during the time you experienced it.

We all know how to get into time travel but how do we get out……..

You don’t need time travel – all you need is life. And what is life? Life is the evolution of the impossible into the inevitable over an infinite amount of time.

if it is shown that if something, such as a solution to a particular class of equations, were possible, then two mutually contradictory things would be true, such as a number being both even and odd. The contradiction implies that the original premise is impossible.

This is called proof by impossibility. Thus if some traveled back in time far enough to kill his grandfather, we have the contradiction and therefore it is impossible.

You could argue that he would be able to time travel, but not kill his grandfather. However almost anything a person does going back in time would cause the same contradiction, thererfore it is the traveling back in time that is impossible.

Actually, it probably is possible to travel back in time, however to do so, you would also have to travel so far in space that you cannot see anything that happened before your current time due to the speed of light, because this to could affect the future.

The reason I am here is that, i really want to go back the day when our matriculation exam was just finished. Everything around me is peaceful and happy. Currently, I am living in dire situation. People are dying outside on the streets. Smokes everywhere. Everything is in doom. Ah, yeah. I really miss my past. If you are reading this, you can judge me in anyways. I just want to live peacefully and happily.

You must live in Portland

I entirely know what you say and how you feel, Robin. I am totally convinced that future is no promise to offer a better place to live. World is becoming unnecessarily more complex and more horrible and more insecure. Therefore, travelling back in time to a point where things were still far away from such ordeals is what I aspire. But I think if it is possible to travel back in time without the possibility of carrying our lived experiences with us, it will be useless as we will be repeating the same mistakes over and over again. Now, this begs the questions “in what type of physique could we imagine ourselves back there if such time travel becomes possible? That is, becoming younger again in a physical regression (as I said this would be a torture without having learned from all these later years)? Or appearing at our desired times in our present physique and age? I believe the most ideal one would be if we appeared at our desired point in time at the same age that we were at that point of time with a good feeling of our later lived experiences.

Mam all u need to do is just run faster as much as u can or visit the black hole because in both condition time just slow it down ….

Time travel is simple. If you do happen to travel to the past you create a new time line not affecting the time line you left. In essence you going to the past is now your future. Even if you were able to return you may never know if you remained in your time-line or created a new one. So even if you changed something in your travels it would happen in the future not the past.

Sorry time traveling is not possible, there is no way you can go into the past or the future ‍♂️. You can only be in the time you are already in.

Incorrect. General relativity allows time travel into the future. You need a space ship that can travel extremely fast though, approaching the speed of light, or you need to get close to a supermassive black hole.

It is travel into the past that there is no known practical way to do, and is probably impossible.

So what happens when we Die? Where do we go? I want to go back in time so I can meet my childhood friends…

Simple question from a simple mind:

At what point, when a person says they are from the future, do we stop throwing them in the funny farm and actually start listening??

When they show actual proof. Not just some random prediction of the future.

I don’t believe that “glimpses into the future” could be possible. If it were so, we could glimpse blueprints of the future that we could bring back to the present and build before they were invented. My personal.beleif is in any time frame there is only one active time which is the present. The past no longer exists and the future hasn’t occurred yet, so there is no such thing as ‘time travel’ except for the frame we are in now.

First off time is not real we make time if you travel anywhere all you are doing is beating the Earth speed try this for a mathematical equation the Earth travels a thousand miles per hour you’re not beating human time that is your own equation the Earth travels a thousand miles per hour a space shuttle travel 17,000 mph you can beat time that you made so time is not real you are only beating the Earth speed if you go in a space shuttle and go around the earth 17,000 miles per hour the Earth only travels a thousand miles per hour plus it has all types of gravitational pull from the Moon Earth’s access on the til t you figure out the mathematical equation I cannot time travel is real if you can beat the Earth speed and we can it has nothing to do with its 12:00 it’s 1:00 that’s not real time is made up as a mathematical equation you can beat the Earth speed you can go back into the Earth’s time in a space shuttle but you’re not beating anything except the Earth’s speed think about that one time is not real at all all it is is a mathematical equation think about that one real long

What I’m trying to say is this a space shuttle travel 17,000 mph the Earth travels a thousand you beat it 16 times faster that’s all you did you’re not beating any time you’re not beating 1:00 you’re not beating 3:00 all you’re doing is beating the Earth’s time you can go in reverse around the Earth 17,000 mph okay you can go forward with the Earth’s centrifugal force 17,000 miles per hour you’re not beating anything you’re beating a mathematically equation that we we created astronauts been traveling time for instance for years and haven’t told us because of the space shuttle that does travel 17,000 mph it beats the Earth speed 16 times a boggles my mind you have the Earth access the moon gravitational pull but you can get in a space shuttle and travel 17,000 miles per hour and beat the Earth’s speed 17 times think about it

If any scientist or anybody can actually answer this question how do you set up this equation with the Earth spinning a thousand miles per hour you have the moon pulling gravity the Earth’s access on until I want to know tell me then wondering for a while this equation popped into my head about 2 years ago I’m not a math whiz or anything I just thought about it weird how the mind works I’m not into space or any space stuff at all I’m Samanthas boy friend John antos wrote this

I liked your post and the knowledge you given. I also written a post on Time Travel.

how would any of that stuff be true because e’*34+Em would stop all the forss of vissecs and how would we do it if you now what i mean??? also thanks for the scuff for my project

I would love it if I had a real life time machine here with me now which could take me to anytime I want, the past, present or future. If I had a time machine here with me now, I would go to the past in September 2004 when I was born and give myself to another family that is actually rich and not this horrible family that I have now.

that not nice

Close but not quite right scientists of the idiotic variety, yes, you don’t want people to travel back in time to mess with their own pasts, of course, but you say it’s impossible, but it’s not, and I’m always ignored with my crazed crackpot theories, so what’s the harm in telling the truth as I see it, while it could be possible to travel to the past, here in lies the problem with rewriting the future, while some believe it’s possible to travel back in time, but it’s very expensive and definitely a one-way trip to the future or to the past. Basically Doc Brown got the mechanism for time travel almost right but the energy out put needs to be quadrupled instead, allowing for the ‘physical item, being or vehicle’ to transport through time without killing the time traveler in question. Wormholes are unpredictable, until warp speed for spaceships are a thing, it is not possible for the space ships to achieve time travel, unless they want to enter a black hole, which I would not recommend. as you need warp speed to survive the emptiness of the black hole, without being ripped to shreds. Say for example, Back to the future 1, the timeline doesn’t erase it continues on without the ‘said time traveler’ in existence basically the Marty from Wimpy George’s timeline did time travel to the past and messed with his parent’s meeting so to speak, but never return to the same timeline therefore Marty A went known as a Missing Child in timeline A, while it continues on without him, however Marty A became Marty B/C, in the Successful George Timeline. So that is what I’m talking about. the timeline changes only for the time traveler themselves the ones who are left behind don’t experience a thing of timeline rewritten-ism, as it would never happen in the first place. The other thing is if you want to mess with your own childhood, to make a better life for the past self, the key thing to remember it’s not really you. It’s an alternative version of you, that you interfered with. creating a parallel timeline to it’s original, yet slightly different. Yes it would be awkward to raise yourself. but as long as you are staying in the past, nothing should happen until the age you traveled back in time, unless of course you touched your past self and suddenly de-aged and merged with your past self, is an option 1, option 2 the future self explodes spreading guts all over the place and therefore the past self, of you became a murderer of your future self, I am more inclined to believe option 1 as option 2 seems a little too out there. Basically you would have two memories one of the former timeline and one of the current different timeline. Still traveling through time is truly a one way trip and if you want to travel through time, you would need some time travel mechanism, the way you scientist talk is basically a dream version, or an OBE version (OUT-OF-BODY-EXPERIENCE) which is basically a vivid/lucid dream which is not true time travel, the true time travel is based on the BTTF Trilogy not the idiotic versions you preach about. I believe I’ve said enough.

Mystery solved and I will explain, I was in a coma 3 months and I experienced things, I traveled time forward and backward, it is not a one way ticket. Movies and songs are recorded on magnetic tape in a VCR tape Cartridge or Cassette tape, Magnetic tape recording works by converting electrical signals into magnetic energy, which imprints a record of the signal onto a moving tape covered in magnetic particles. 3D life on earth(a movie), and the Magnetosphere all around earth coming from the core of earth(MAGNETIC ACTIVITY) without Atom Made Tape, is like a movie on magnetic Atom made tape in a VCR tape cartridge. Revolution and Rotation is the motor(VCR).

This is why people have those freaky Deji’vu feelings like they have lived this before, BECAUSE YOU HAVE, and how people can be psychic, and how there is Prophecy in the Bible. When a person dies, their Spirit- MIND(Thoughts, Feelings, Urges(Physical and mental personality)) breaks out of human body- a stopped heart is what releases the spirit from the human body. Then the Soul(Life) with the memory of your existence in it breaks out of spirit and goes back to your birthday with a erased memory, meanwhile your spirit goes back in time to when you were a teenager starting the mental puberty, maturity from that adult spirit you died with in last life.In that old movie Star Wars or maybe it was the Empire Strikes Back, there is a scene where Princess Laya plays like a 3D movie, that is EXACTLY how its of life on earth.

If only wish I could undo everything what I’ve done wrong in the past, I’d be more happier

And that my friend is absolutely what you do not or would not know. Everyone focuses on what they don’t or haven’t had rather than what positives they do have around them. To change the ingredients of a past life only changes the flavour you have in this life, it does not make you happier.

No, travel to the future is not possible. Like, future is unpredictable and always have been so give up on that field

Already has been, and has been proven.

Time travel is not so possible for every one , but there are already time travelers on earth #@*

Who are these time travelers?

Depends if it is the Governments (they done it since the 80s), or if it was a Accidental travel, or a simple us creating our own machine. Either way, one can easily find storys, and other evidence with a good research. I have a website that shows the effects of change cause by time travel.

They are out their (done by the government since the 80s) but the future is open with time travel (told its open since 2028) so they travel back much.

Time travel 101-

Create a closed loop circuit around a full metal structure, hermetically seal it and bring O2, Use two tesla coils to create north and south poles. (Artificial Magneto sphere.) Make sure to pain the outside in lead to prevent any cosmic rays from penetrating the materials on the inside. (Radiation = bad). Connect a ball made of w/e with wires that alternate the current from the coils to w/e panel on the outside of the structure to make it move via inductive magnetic / electric Lorentzo (Lorentzo = ExMfield = Velocity. = Antigravity) Create Antigravity by using forces from the inside reactor. (Pressurized Mercury, and Tesla Turbine.) Then Move 10-100x faster than light depending on the charged field, Friction will be added to the electric field instead of the craft allowing the G-forces not to crush you inside. The field will take the pressures of outer space, The temperature of space will allow for super conductivity of the structure.

Eventually you will arrive in the future, if you stay in one place. but account for the movement of earth in your travel log. To see outside you will need a monitor / camera system, as any leaks through a viewing area will cause death by radiation from the cosmic rays from the field you have created.

The O2 can be used as a backup generator, through air pressure and the tesla turbine.

There are many different ways to make wormholes, but the curvature of space is really hard to calculate to send a machine far out to the end and create a link with the machine that wants to travel there. And leaving one behind to get back.

If you can imagine it, it can be done. You just need the knowledge of not dying to complete it.

U.S.S. Tourist, You’re a time traveler or just insanely smart.

You don’t need to go the speed of light. Human Time is recorded in the magnetospere as a movie is record, ed on magnet VCR Tape or a song on a record. A VCR or record does not have to go light speed to retrieve the recorded info. All of life is recorded in 3D by our Magnetosphere. My Analogy is imagine a VCR tape cartridge being the earth, imagine life on earth being the movie but in 3D with out adom made tape, imagine Rotation and Revolution of Earth being the VCR putting all in to motion- playing. That is how its done, the magnetosphere kills two birds with one stone, it protects earth and records time, human time is in a magnetic bubble that is why the Bible refers our time is different from gods time and this is how God the maker(PLANET OF UNITED SUPREME BEINGS) can flip through our time to know everything. By the way long before life on earth, he built the original 7 wonders of world(Pyramids) to Pump the Seven gasses into the atmosphere of this planet found in the goldilocks zone, so Life can live on it, and that life of all types is his technological cyborgs that grow and multiply on earth also he seeded it with plant, trees, sea creature and things that fly,. Anyway that above is how time is recorded.

Until recently, I thought my neighbor was a crackpot until he actually invented a time machine. He utilized an ordinary closet, and showed me the sophisticated (to me) instrumentation he had installed. I was very skeptical at first, until he offered a small demonstration and entered the time coordinates and energized his invention. To my amazement, when I opened the door, the clock on the wall was 30 minutes later than when we stepped into the machine. OMG!!! Destroy this thing before it destroys us!!!.

So happy to have my husband back after 6 months of separation. get any kind of relationship/marriage help you want from….Robinsonbuckler11 @gmail com………………………

I find it odd that people say time travel isn’t possible yet… If time travel is possible, it has always existed. Meaning, there is not past present it future, only our perception of time. What we know as past present and future have always been occurring simultaneously, so travel was invited the moment the universe wss formed. Dinosaurs are roaming the earth right now, and forever. A version of me is typing this and has always been typing this, within this perceived moment of “time” and time travel has always happened, whether or not we exist in that reality at the right “time” to observe time travel is the only question.

I find it odd that people say time travel isn’t possible yet… If time travel is possible, it has always existed. Meaning, there is no past present or future, only our perception of time. What we know as past present and future have always been occurring simultaneously, so travel was invited the moment the universe was formed. Dinosaurs are roaming the earth right now, and forever. A version of me is typing this has always been typing this, within this perceived moment of “time” and time travel has always happened, whether or not we exist in that reality at the right “time” to observe time travel is the only question.

Their had to be one point however, when it was created and started, and for that, there was nothing but the current time. Once it was created, than we had a pass, present and future to which we can go back to millions of years to see Adam and Eve with the dinosaurs or go millions of years in the future. However, given the events that changes, each time a new time line has been created. We also have destroyed the planet and repopulated many times in the last million years. Each event changed, or something we do different (without traveling) enters a new universe where some things may be different or the same. Today are universe are shifting a lot.

To be fair, even if it is a one way trip into the past, that doesn’t stop machines going back. We could send a machine back and order it to do anything we want and then tell it to meet us at a certain time in the future. We send it back, then go straight to the meeting point we agreed and then we’ll be able to prove if it worked or not.

I’m a girl who has read a book about seeing future through a box. So is it actually possible?

Time travel has been done on purpose by the Government since the late 1980s. From research, the mostly use kids, or future Presidents. Their are some cases where people have been struck by lightning or came across some tragically event that cause them to leave their timeline either forward or behind in time. The Mandela Effect is the current cause of how things go wrong when time travel is not done right. Click on my name to see the website.

Even as traveling to a location as a future or pass date is possible as what people here mean. However, as you said, it is numbers. Time is a illusion and we do not travel threw time, just universe that are different than ours. What we call time dates and months is what changes each universe. We are all from different universes today as they came together. The mandela effect is a fine example.

thx to eleon wont we soon be able to digitize our conscious being, then accelerate that data pass the speed of light some how then download it into some android or something…..i dunno…..just a thought

I want to go to my elementary school again. Someone help me out, I know its Idiotic but stil.. I am not good at science. As far I understood, 1) we can trace through time if we travel fast than speed of light.. I think memory os the only thing that is faster than light, Yeah I can go to Paris within 1 sec in my memory but yeah its illustion, i want in real 2) Through Blackhole – I think its Bermuda triangle

if you travel back in time you will still be your age now. That is how it worked with others. No one gets younger otherwise traveling to far back would kill you. No school would let you return to school as a adult so not possible.

Plz help me I just want to send a message to myself in my past and save my self from a beast plz help Nazneen

Would love to experience many moments in life again for the first time again!

I think that time traveling should be left alone, for the sake of humanity. There are some things we’re not ready for yet.

Well stephen hawking may be wrong. I mean, the study proved that the universe self corrects itself to prevent inaccuracies. So maybe tourists from past do visit us but we don’t remember them as the universe alters our memory. If you guys have read about Butterfly Effect, a simple mistake today may grow through years to become a giant disaster in future so if you think of it, oncoming tourists from future may cause giant inaccuracies. Imagine this, You have travelled to past. You brought two cakes for yourself, so you pay the shopkeeper 20$. The shopkeeper invests the 20$ in stocks, strikes gold there and becomes a rich businessman.His daughter goes to Cambridge and marries someone else than the person she was supposed to marry according to time. Can you imagine the magnitude of inaccuracy after 100 years? Therefore, whatever the tourists from future do, is corrected by the universe and we don’t remember it. Creepy, but food for thought.It also adds a special meaning to the word ‘Fate’.

How much wacky terbacky (i.e. weed) you be smokin’ JOE JOE?

Hmmmm…. As brilliant of a mind as Stephen Hawkins was, how is he so sure that he would even recognize hordes of tourists from the future? Almost everyone is aware of the warning of the Butterfly Effect. So I’m sure any future visitors Intelligent enough for Past-Time travel would be amply attuned to this.

Most future people coming to the pass (our time) seems careless and not intelligent. Most are taking FBI lie detector test and telling us what is happening in the future. That is a bad idea, because if you tell us (example) who is the next President, and the Government does not like the person they than can change that event to let someone else in (as seen in 2020) One should never acknowledge who he or she is or why they are their. Most traveling is to get knowing of the pass or to pick up certain things. Since are pass is changing, events are changing and are timelines are messed up, someone made a mistake. The Mandela Effect is a fine example.

Wow that’s great plz help me go to my past plz,I can’t do it by my own at least help me send a msg to myself in my past Nazneen

I think it is possible, but time traveling is really just changing universe created by different time lines. Our whole solar system is in a whole different place now and Earth is much smaller in this universe from the one I grew up end. Someone has already changed the timeline.

Roads? Where we’re going, you don’t need roads!

Youre wrong about your measurement of speed for traveling, in order for time to slow down, with inside an object compared to outside. Scientists proved that time with inside an object at an excelorated speed actually appeared to have slown down during the duration of time for the test. The speed was far less then the terminal speed of a rocket for NASA at 256,000 kms p/h.

In to the volicity of space. Generating a vacuum of space, could be no different the the actual transport of matter over frequency where in fact matter can be carried by sound. It is believed that an alien civilization harnessed this energy in the form of bolisks that where believed to carry the same properities and in consideration of harmonic resinance, the simularities could be used in order to carry large weight. In accordance with a documentry on theoretical science.

However the properties, present the fact that a working property controdicts your counter intuative theory of gravitational deceloration of matter to colide within itself to absorb all things into non existance as to the transfer of matter into energy, rather then your idiolisms of transfer between dimentional space to another destination that is not linked or the transfer between time that isnt, either.

However to reproduce the fabric of time within space in a practical measurement as I have mentioned, would put an end to all the lunacy of an unmeasureable field, which people fail to identify. Like running into a glass window. Only to not know what forcefield is present.

Time travel into the past can be achieved simply going faster than the speed of light.

The closer you get to the speed of light the slower time goes

If you reach the speed of light time stops

If you go faster than the speed of light it starts to reverse

Why does no one seem to know this?

Christopher Reeves did this in Superman 3 brah.

Any time travel, pass and future, is by going faster than the speed of light. It is said by reversing that that you can go back in time. However, I assume since the Government has done this since the 80s they have better ways (maybe tying in a date) and not having to go to a unknown date.

I want to send a message to myself in the past on a particular date plz can you help me, this means a lot lot lot to me,plz help me Nazneen

Why don’t we drop the declaratory statements that it “is or isn’t possible!” Until someone actually does so. Just say “maybe”.

People have and their are records both to the pass and future. The Government has done it since the 80s as part of the “star wars project” and are much better at it today. This explains the black holes in the sky of 2019, and the CERN destroying 5 parallel universes in 2013. We also see changes because of time travel events changing time. The Mandela Effect is a find example.

I want to send a msg to myself and my family in the past ,is it possible plz help me my life will be saved one who helps me saves me and my kids from a pack of beasts,

The worst idea ever. We all want to do this and where does it stop. A lottery win does not sound bad if you knew the actual location, time and place. After a while though, would you not want to write that hit song, become the author of the Harry Potter books, stop 9/11? The idea of giving your pass self (a time time travel was not proven) information of the future could change things in a major way. This would cause one small thing to change creating many others to change. This has already happen in simple ways of the The Berenstein Bears changing to The Berenstain Bears. This is a small event but this event “The Mandela Effect” now has over 3,000 changes.

What if you decided to give your pass self information about a lottery ticket that would be a winner, bought late at night and he was hit by a car on the way to get it. Changes the whole future. However, If detailed right, done right, with no large changes, it may not effect much, but to know your being given info from yourself in a future time (when that was not known much or provrn back than) You would either assume it is a joke or you gone crazy.

I don’t want to win a lottery, my decision about my career and studying was right but my family and their cruelty has put me into this worst condition I just want to go back complete my studies and live a life like a human not like a animal or slave,help me plz Nazneen

Can someone take me to 2013? i can pay later to all of you in bitcoins so its a win win and you dont need to do anything, just wait

LOL but still complicating on my side

You travel in your dreams where time and space colloids ..That’s y sometimes the dream which you dreamt might be a 10 mins reel time but you felt dreaming whole time like 6 to 8hrs .. Probably even traveling to parallel universe

I agree. Dreams as we know it is not a simple sleep. The part of the brain we do not use while awake, we use at night. This is the phenomenon part of the brain that can do thing we feel a human can not do. We of course use less than 30% of our brain. By the use of 100% of the brain we would use both sides and be able to do common things such as read thoughts, move things without touching them etc. The idea of using this side of the brain, would be the theory we can leave our bodies and visit different universe, see what could of happen shall we done something different, and even see future events. This may be why we notice different memories to some things as we could of held some from another reality.

It would be very weird, however, if we were trapped in that universe, or another body and fail to return to ours. Is that how people die in their sleep?

i just fell like going to late 70’s, where i can see majority of family.. i am willing to trade life for it…..

Time travel to the pass is just as common as the future. However, as both has been done it is NOT travel threw time. Time is a illusion we created. We are actually traveling threw different universe with (what we call) different time, dates, years, etc. The Mandela Effect is a find example how traveling threw different reality’s change the time lines.

As a add on to the above, Time travel is not a theory, has been proven, and has been done by the Government since the 1980s. Their is many residue in our history to even show some time travel storys to be real.

Where can one get a reverse watch, is it really possible to go back in past with its help, is it sooo easy ,plz help me ??????? Nazneen

US20060073976A1- search this patent number,this describes the process for time travelling,I really don’t think magnetic energy will work,maybe heat focused on a specific point could expand the fabric of space and make a hole in it.even then I will the hole take you to another time.it would be one thing to time travel but selecting a point in time would be impossible.you could only travel to the time you device was built?

Is there a watch which back travels in time or reverse time watch? Is it true? How to get one? But with that how can I send a message to myself in my past, plz help Nazneen

I don’t believe such a watch exist and their are plenty of smart minds with huge funds trying to travel.right now there are only theories.

Thank you very much for your response. I just want to send a message to myself in my past. Nothing much will be changed but 3 literally dying devastating lives will be saved. We are suffering for the mistakes and egoistic arrogance of others so if possible plz help me

Traveling back in time isn’t just a when problem, it’s a *where* problem. Where was the place you’re standing right now a thousand years ago, or a thousandth of a second ago? There is no useful answer to those questions, so there’s nowhere to travel back in time to.

Traveling forward in time? You’re doing it now.

when you step through a door is time lost when you come back through? lets say you return days Later how much time did you loose. what exactly is Time,.? is dialation a safe way to return ,. a Blackhole will assist you in in travel, the question is will you arrive safe,.

Traveling back in time is impossible. 2 reasons why that are never taken into account.

A) The stuff you are made of ( subatomic material) is being used by something else. It I not like you are a facsimile of the already existing material. What you are made of is exactly the same existing material. The problem is exact stuff can not exist in 2 different places in the same point in time. You will either : Decompile or fall out of phase with the universe. Both bad outcomes for the time traveler.

B) Lets look at it from logical commonsense. You have a bar of gold . You intend to send the bar back 1 second in time. Now you have 2 bars of gold . You send those 2 bars back one second . You have 4 bars …… do that 50 times . You have over 900 trillion bars of gold. All made of the exact subatomic particles. The more the bars back the more the existing mass of the universe increase. What are the consequences of changing the mass of the universe . Hence the paradox . Information can not be destroyed., It also can not be created.

At least this is the way my brain perceives going back in time.

Time is a function of change. None of the 4 forces The strong force , The weak force , Electromagnetism and Gravity can not work without time.

I will figure out time travel one day but only for the past.

I wish I could travel back to 18th of June to save my mom.

Is time travel really a one way ticket? Theoretically, if you can go one way, you should be able to go back.

Time is not one way. It’s consequences are however irreparable given certain circumstances and is not something that should be taken lightly or thought of in a manner of disregard. I’ve only very recently decided to take to your social platforms regarding space and time.

You can try finding me on Instagram. I’m not familiar with these platforms to better direct you there. My Instagram name is johnrvh

On Twitter it seems to be @_JohnRvH

If I go forward I will have to pay extra bills and taxes. I don’t think I can afford it.

You’re the first person I’ve come across in this timeline that has a sense of humor. Thankfully, going forward is not possible if that future hasn’t been created yet.

timetraval is no joke if its created the whole universe could go out of orbit.

Cauchy problem converging to non minimal terraces as t → +∞

Stephen Hawking may he rest in peace a genius but not all knowing. As far as he knows we haven’t been flocked by tourists, in the same maybe these UFO sightings are actually time travelers from the future coming to the past to view how we really lived why things really happened the way they did, etc. To limit the imagination of possible and impossible is wrong then you create fantasy. And we have learned from history that there is truth in fantasy. I.e. the different mythos of the different ancient cultures from around the world including those of the Norse. Improbable and probable should be more appropriate. It’s possible because it can be imagined improbable die to the right math or this or that not existing or matching up. I also believe that if time travel to the past were possible that the changing of something in the past would create a new timeline running current with your timeline at which will inevitably collide and will cause the collapse of the universe at which point a new universe will be born.

so i think the speed of light is only relative to deciding a point of destination -initially- as specific gravity of destination needs to be ascertained to calculate the frequency needed to run an alcubierre-white engine to bend space correctly to cross space ‘quickly’, the point of reference may well be jupiter in our solar system for the fact of the moons that orbit it, i surmise that by using a ‘dead end ‘ equation that usually puts notable mathematicians into the outer regions by trying to solve it may actually be the key as calculations end in a loop of 4-2-1 ie 3N+1; this process of calculation creates a sine wave over time/distance relative to specific gravity of chosen destination – as time is determined by gravity therefore if the speed of light to a destination can be used to ascertain the specific gravity of a ‘body’ to visit ie a star or sun due to receivable resonant frequencies emitted by the body, then the constrictions of the speed of light do not exist other than to give a constant, by using the 3N+1 method of calculation ,once the speed of light and returning resonant frequencies of a destination are determined the calculation can be extrapolated to match the distance giving the end point -in doing this the sine wave required can be ascertained and be condensed to create a wormhole and allow the alcubierre-white engine to ‘bend or distort space enough so that the bubble you are in matches the required specific gravity of the destination – the frequency of the body nearest to the destination point should be used and resonated inside the bubble to create synchronicity of frequency and cause attraction i also believe that travelling through space require the ability to see things from different perspectives and it requires the ability to navigate through a series of what may be described as “Aims Windows” where your point of view needs to change inherently with a given position at a given point in the galaxy

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Will We Ever Be Able to Time Travel Into the Past?

Forward or back—which will it be?

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You likely don’t realize it, but when you’re done reading this article, you will have traveled perhaps 90 seconds into the future. The truth is that it is easier, theoretically speaking, to travel forward in time than it is to travel backward, and that’s partly because we’re all moving forward in time naturally.

The possibility of time travel stems from Albert Einstein’s theory of special relativity, which, loosely speaking, describes the relationship between space and time. An outgrowth is something known as “time dilation,” which suggests that time can move at different rates for different observers—and therefore at different rates in different places. This theory is borne out by the (rather freaky) fact that clocks on the space shuttle—whether internal clocks or atomic clocks placed aboard for experimental purposes—run more slowly than reference clocks on Earth. In this sense, astronauts on extended missions may already be considered time travelers, as they arrive home very slightly later than the elapsed time measured on their own instruments would suggest. Moreover, “Time beats faster on the moon than on Earth, and time beats slower on Jupiter,” says celebrated physicist Michio Kaku of the City College of New York. “So if you were to simply camp out on the moon or Jupiter, you’d be going backward and forward in time. Now, of course, these are for fractions of a second.”

A more useful implication of time dilation is the fact that the closer to the speed of light you’re moving, the slower your internal clock will be ticking relative to time on Earth. “If you reach 99 percent of the speed of light and spend like a year moving at that speed—around the solar system, say—and then come back to Earth, you will find that the Earth has moved on, 100 to 200 years into the future,” says Dr. Ulvi Yurtsever, coauthor of a seminal paper on time travel. So, in theory, if we could improve propulsion systems enough, we could skip ahead centuries. But we still couldn’t move backward.

Indeed, backward time travel, while theoretically possible, is far trickier and would involve black holes and “tunable wormholes” and more energy than a kindergarten class on a sugar binge. “You can write down solutions of the equations,” says Clifford V. Johnson, a professor of theoretical physics at USC, “and those equations tell you two things: how you twist up space and time, and what matter you need to do that. And every time you get those weird twists in space and time that look like a time machine, the matter and energy you need to do that is in a form that may not exist in this universe. So that’s just a fancy way of saying that the jury is out.”

Ryan North, author of the recently published book How to Invent Everything: A Survival Guide for the Stranded Time Traveler , argues that by going backward, we could advance society hundreds of thousands of years. Even so, North muses that if we had a single shot at round-trip time travel, the better choice might be to plunge ahead. “Download the equivalent of Wikipedia onto a thumb drive and bring it back,” he says. “I’m all about stealing ideas from the future.”

So there you have it: 25th century, here we come.

Do you have unusual questions about how things work and why stuff happens? This is the place to ask them. Don’t be afraid. Nobody will laugh at you here. Email ­[email protected].

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Time travel: Is it possible?

Science says time travel is possible, but probably not in the way you're thinking.

Albert Einstein's theory

• General relativity and GPS
• Wormhole travel
• Alternate theories

Science fiction

Is time travel possible? Short answer: Yes, and you're doing it right now — hurtling into the future at the impressive rate of one second per second. 

You're pretty much always moving through time at the same speed, whether you're watching paint dry or wishing you had more hours to visit with a friend from out of town. 

But this isn't the kind of time travel that's captivated countless science fiction writers, or spurred a genre so extensive that Wikipedia lists over 400 titles in the category "Movies about Time Travel." In franchises like " Doctor Who ," " Star Trek ," and "Back to the Future" characters climb into some wild vehicle to blast into the past or spin into the future. Once the characters have traveled through time, they grapple with what happens if you change the past or present based on information from the future (which is where time travel stories intersect with the idea of parallel universes or alternate timelines). 

Related: The best sci-fi time machines ever

Although many people are fascinated by the idea of changing the past or seeing the future before it's due, no person has ever demonstrated the kind of back-and-forth time travel seen in science fiction or proposed a method of sending a person through significant periods of time that wouldn't destroy them on the way. And, as physicist Stephen Hawking pointed out in his book " Black Holes and Baby Universes" (Bantam, 1994), "The best evidence we have that time travel is not possible, and never will be, is that we have not been invaded by hordes of tourists from the future."

Science does support some amount of time-bending, though. For example, physicist Albert Einstein 's theory of special relativity proposes that time is an illusion that moves relative to an observer. An observer traveling near the speed of light will experience time, with all its aftereffects (boredom, aging, etc.) much more slowly than an observer at rest. That's why astronaut Scott Kelly aged ever so slightly less over the course of a year in orbit than his twin brother who stayed here on Earth. 

Related: Controversially, physicist argues that time is real

There are other scientific theories about time travel, including some weird physics that arise around wormholes , black holes and string theory . For the most part, though, time travel remains the domain of an ever-growing array of science fiction books, movies, television shows, comics, video games and more. 

Einstein developed his theory of special relativity in 1905. Along with his later expansion, the theory of general relativity , it has become one of the foundational tenets of modern physics. Special relativity describes the relationship between space and time for objects moving at constant speeds in a straight line. 

The short version of the theory is deceptively simple. First, all things are measured in relation to something else — that is to say, there is no "absolute" frame of reference. Second, the speed of light is constant. It stays the same no matter what, and no matter where it's measured from. And third, nothing can go faster than the speed of light.

From those simple tenets unfolds actual, real-life time travel. An observer traveling at high velocity will experience time at a slower rate than an observer who isn't speeding through space. 

While we don't accelerate humans to near-light-speed, we do send them swinging around the planet at 17,500 mph (28,160 km/h) aboard the International Space Station . Astronaut Scott Kelly was born after his twin brother, and fellow astronaut, Mark Kelly . Scott Kelly spent 520 days in orbit, while Mark logged 54 days in space. The difference in the speed at which they experienced time over the course of their lifetimes has actually widened the age gap between the two men.

"So, where[as] I used to be just 6 minutes older, now I am 6 minutes and 5 milliseconds older," Mark Kelly said in a panel discussion on July 12, 2020, Space.com previously reported . "Now I've got that over his head."

General relativity and GPS time travel

The difference that low earth orbit makes in an astronaut's life span may be negligible — better suited for jokes among siblings than actual life extension or visiting the distant future — but the dilation in time between people on Earth and GPS satellites flying through space does make a difference. 

Read more: Can we stop time?

The Global Positioning System , or GPS, helps us know exactly where we are by communicating with a network of a few dozen satellites positioned in a high Earth orbit. The satellites circle the planet from 12,500 miles (20,100 kilometers) away, moving at 8,700 mph (14,000 km/h). 

According to special relativity, the faster an object moves relative to another object, the slower that first object experiences time. For GPS satellites with atomic clocks, this effect cuts 7 microseconds, or 7 millionths of a second, off each day, according to the American Physical Society publication Physics Central .  

Read more: Could Star Trek's faster-than-light warp drive actually work?

Then, according to general relativity, clocks closer to the center of a large gravitational mass like Earth tick more slowly than those farther away. So, because the GPS satellites are much farther from the center of Earth compared to clocks on the surface, Physics Central added, that adds another 45 microseconds onto the GPS satellite clocks each day. Combined with the negative 7 microseconds from the special relativity calculation, the net result is an added 38 microseconds. 

This means that in order to maintain the accuracy needed to pinpoint your car or phone — or, since the system is run by the U.S. Department of Defense, a military drone — engineers must account for an extra 38 microseconds in each satellite's day. The atomic clocks onboard don’t tick over to the next day until they have run 38 microseconds longer than comparable clocks on Earth.

Given those numbers, it would take more than seven years for the atomic clock in a GPS satellite to un-sync itself from an Earth clock by more than a blink of an eye. (We did the math: If you estimate a blink to last at least 100,000 microseconds, as the Harvard Database of Useful Biological Numbers does, it would take thousands of days for those 38 microsecond shifts to add up.) 

This kind of time travel may seem as negligible as the Kelly brothers' age gap, but given the hyper-accuracy of modern GPS technology, it actually does matter. If it can communicate with the satellites whizzing overhead, your phone can nail down your location in space and time with incredible accuracy. 

Can wormholes take us back in time?

General relativity might also provide scenarios that could allow travelers to go back in time, according to NASA . But the physical reality of those time-travel methods is no piece of cake. 

Wormholes are theoretical "tunnels" through the fabric of space-time that could connect different moments or locations in reality to others. Also known as Einstein-Rosen bridges or white holes, as opposed to black holes, speculation about wormholes abounds. But despite taking up a lot of space (or space-time) in science fiction, no wormholes of any kind have been identified in real life. 

Related: Best time travel movies

"The whole thing is very hypothetical at this point," Stephen Hsu, a professor of theoretical physics at the University of Oregon, told Space.com sister site Live Science . "No one thinks we're going to find a wormhole anytime soon."

Primordial wormholes are predicted to be just 10^-34 inches (10^-33 centimeters) at the tunnel's "mouth". Previously, they were expected to be too unstable for anything to be able to travel through them. However, a study claims that this is not the case, Live Science reported . 

The theory, which suggests that wormholes could work as viable space-time shortcuts, was described by physicist Pascal Koiran. As part of the study, Koiran used the Eddington-Finkelstein metric, as opposed to the Schwarzschild metric which has been used in the majority of previous analyses.

In the past, the path of a particle could not be traced through a hypothetical wormhole. However, using the Eddington-Finkelstein metric, the physicist was able to achieve just that.

Koiran's paper was described in October 2021, in the preprint database arXiv , before being published in the Journal of Modern Physics D.

Alternate time travel theories

While Einstein's theories appear to make time travel difficult, some researchers have proposed other solutions that could allow jumps back and forth in time. These alternate theories share one major flaw: As far as scientists can tell, there's no way a person could survive the kind of gravitational pulling and pushing that each solution requires.

Infinite cylinder theory

Astronomer Frank Tipler proposed a mechanism (sometimes known as a Tipler Cylinder ) where one could take matter that is 10 times the sun's mass, then roll it into a very long, but very dense cylinder. The Anderson Institute , a time travel research organization, described the cylinder as "a black hole that has passed through a spaghetti factory."

After spinning this black hole spaghetti a few billion revolutions per minute, a spaceship nearby — following a very precise spiral around the cylinder — could travel backward in time on a "closed, time-like curve," according to the Anderson Institute. 

The major problem is that in order for the Tipler Cylinder to become reality, the cylinder would need to be infinitely long or be made of some unknown kind of matter. At least for the foreseeable future, endless interstellar pasta is beyond our reach.

Time donuts

Theoretical physicist Amos Ori at the Technion-Israel Institute of Technology in Haifa, Israel, proposed a model for a time machine made out of curved space-time — a donut-shaped vacuum surrounded by a sphere of normal matter.

"The machine is space-time itself," Ori told Live Science . "If we were to create an area with a warp like this in space that would enable time lines to close on themselves, it might enable future generations to return to visit our time."

Amos Ori is a theoretical physicist at the Technion-Israel Institute of Technology in Haifa, Israel. His research interests and publications span the fields of general relativity, black holes, gravitational waves and closed time lines.

There are a few caveats to Ori's time machine. First, visitors to the past wouldn't be able to travel to times earlier than the invention and construction of the time donut. Second, and more importantly, the invention and construction of this machine would depend on our ability to manipulate gravitational fields at will — a feat that may be theoretically possible but is certainly beyond our immediate reach.

Time travel has long occupied a significant place in fiction. Since as early as the "Mahabharata," an ancient Sanskrit epic poem compiled around 400 B.C., humans have dreamed of warping time, Lisa Yaszek, a professor of science fiction studies at the Georgia Institute of Technology in Atlanta, told Live Science .  

Every work of time-travel fiction creates its own version of space-time, glossing over one or more scientific hurdles and paradoxes to achieve its plot requirements. 

Some make a nod to research and physics, like " Interstellar ," a 2014 film directed by Christopher Nolan. In the movie, a character played by Matthew McConaughey spends a few hours on a planet orbiting a supermassive black hole, but because of time dilation, observers on Earth experience those hours as a matter of decades. 

Others take a more whimsical approach, like the "Doctor Who" television series. The series features the Doctor, an extraterrestrial "Time Lord" who travels in a spaceship resembling a blue British police box. "People assume," the Doctor explained in the show, "that time is a strict progression from cause to effect, but actually from a non-linear, non-subjective viewpoint, it's more like a big ball of wibbly-wobbly, timey-wimey stuff." 

Long-standing franchises like the "Star Trek" movies and television series, as well as comic universes like DC and Marvel Comics, revisit the idea of time travel over and over. 

Related: Marvel movies in order: chronological & release order

Here is an incomplete (and deeply subjective) list of some influential or notable works of time travel fiction:

Books about time travel:

• Rip Van Winkle (Cornelius S. Van Winkle, 1819) by Washington Irving
• A Christmas Carol (Chapman & Hall, 1843) by Charles Dickens
• The Time Machine (William Heinemann, 1895) by H. G. Wells
• A Connecticut Yankee in King Arthur's Court (Charles L. Webster and Co., 1889) by Mark Twain
• The Restaurant at the End of the Universe (Pan Books, 1980) by Douglas Adams
• A Tale of Time City (Methuen, 1987) by Diana Wynn Jones
• The Outlander series (Delacorte Press, 1991-present) by Diana Gabaldon
• Harry Potter and the Prisoner of Azkaban (Bloomsbury/Scholastic, 1999) by J. K. Rowling
• Thief of Time (Doubleday, 2001) by Terry Pratchett
• The Time Traveler's Wife (MacAdam/Cage, 2003) by Audrey Niffenegger
• All You Need is Kill (Shueisha, 2004) by Hiroshi Sakurazaka

Movies about time travel:

• Planet of the Apes (1968)
• Superman (1978)
• Time Bandits (1981)
• The Terminator (1984)
• Back to the Future series (1985, 1989, 1990)
• Star Trek IV: The Voyage Home (1986)
• Bill & Ted's Excellent Adventure (1989)
• Groundhog Day (1993)
• Galaxy Quest (1999)
• The Butterfly Effect (2004)
• 13 Going on 30 (2004)
• The Lake House (2006)
• Meet the Robinsons (2007)
• Hot Tub Time Machine (2010)
• Midnight in Paris (2011)
• Looper (2012)
• X-Men: Days of Future Past (2014)
• Edge of Tomorrow (2014)
• Interstellar (2014)
• Doctor Strange (2016)
• A Wrinkle in Time (2018)
• The Last Sharknado: It's About Time (2018)
• Avengers: Endgame (2019)
• Tenet (2020)
• Palm Springs (2020)
• Zach Snyder's Justice League (2021)
• The Tomorrow War (2021)

Television about time travel:

• Doctor Who (1963-present)
• The Twilight Zone (1959-1964) (multiple episodes)
• Star Trek (multiple series, multiple episodes)
• Samurai Jack (2001-2004)
• Lost (2004-2010)
• Phil of the Future (2004-2006)
• Steins;Gate (2011)
• Outlander (2014-2023)
• Loki (2021-present)

Games about time travel:

• Chrono Trigger (1995)
• TimeSplitters (2000-2005)
• Kingdom Hearts (2002-2019)
• Prince of Persia: Sands of Time (2003)
• God of War II (2007)
• Ratchet and Clank Future: A Crack In Time (2009)
• Sly Cooper: Thieves in Time (2013)
• Dishonored 2 (2016)
• Titanfall 2 (2016)
• Outer Wilds (2019)

Additional resources

Explore physicist Peter Millington's thoughts about Stephen Hawking's time travel theories at The Conversation . Check out a kid-friendly explanation of real-world time travel from NASA's Space Place . For an overview of time travel in fiction and the collective consciousness, read " Time Travel: A History " (Pantheon, 2016) by James Gleik. 

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Vicky Stein is a science writer based in California. She has a bachelor's degree in ecology and evolutionary biology from Dartmouth College and a graduate certificate in science writing from the University of California, Santa Cruz (2018). Afterwards, she worked as a news assistant for PBS NewsHour, and now works as a freelancer covering anything from asteroids to zebras. Follow her most recent work (and most recent pictures of nudibranchs) on Twitter. 

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Time travel is mathematically possible, but don't expect it anytime soon

It may sit firmly in the realm of science-fiction, but time travel is a mathematical possibility, even if it won't ever be a reality. Read more: Theory claims to offer the first 'evidence' our Universe is a hologram

Ben Tippett, from the University of British Columbia, and David Tsang, from the University of Maryland, have devised a mathematical framework for travelling through time, and while the name of the paper , "Traversable acausal retrograde domains in spacetime", might spell out the acronym TARDIS, the pair is serious about its implications.

"People think of time travel as something as fiction," says Tippett. "And we tend to think it's not possible because we don't actually do it. But, mathematically, it is possible."

The method relies on the invention of a material, which the pair refers to as "exotic matter." This exotic matter is described as special because it can bend spacetime in a way that time slows down. Exactly what could constitute exotic matter is not explained in the paper, and WIRED has asked the researchers for clarification.

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In flat spacetime, planets and stars move in straight lines. We already know large objects bend the spacetime around them because of their intense gravity – a phenomenon outlined by Einstein in his theory of general relativity – making the path of light around them bend. The exotic matter mentioned in the new paper is described as being capable of bending the time part of spacetime too.

"The time direction of the spacetime surface also shows curvature. There is evidence showing the closer to a black hole we get, time moves slower," explains Tippett. "My model of a time machine uses the curved spacetime to bend time into a circle for the passengers, not in a straight line. That circle takes us back in time."

In particular, Tippett and Tsang’s paper describes a "bubble" of spacetime. This bubble moves through spacetime at speeds greater than the speed of light meaning it can move back in time. Within the bubble are two people, person A is inside person B is outside. Both experience time in different ways.

Inside the bubble, A will see B's events periodically move forwards, and then backwards. Outside the bubble, observer B will see two versions of A emerge from the same location. This means the external observer would see two versions of the objects inside the "time machine": one version moving forwards in time, the other backwards.

****: The arrow of time, as we know it, always points forward. Inside the bubble, this is not the case; because of the ‘exotic matter’, the bubble can move back in time.

** **: The authors describe the concept using two people – A and B. A is inside, and B is outside the bubble. Both person A and person B experience time in dramatically different ways.

****: Within the bubble, A will see the B's events periodically evolve, and then reverse, the authors explain. Outside the bubble, observer B will see two versions of A emerge from the same location: one's clock hands will turn clockwise, the other counterclockwise.

****: This means the person outside the bubble, B, would see two versions of the objects inside the time machine. One moves forwards in time, the other backwards.

"We present geometry which has been designed to fit a layperson's description of a 'time machine'," the researchers write. "It is a box which allows those within it to travel backwards and forwards through time and space, as interpreted by an external observer."

"The inclusion of such a bubble in a spacetime will render the background spacetime non-orientable, generating additional consistency constraints for formulations of the initial value problem" says Tippett. "The spacetime geometry is geodesically incomplete, contains naked singularities, and requires exotic matter."

But while it is possible to describe this type of time travel using maths, and the pair insists the maths is sound, Tippett doubts a machine will ever make it work. "HG Wells popularised the term 'time machine' and he left people with the thought that an explorer would need a 'machine or special box' to actually accomplish time travel," Tippett says.

"While is it mathematically feasible, it is not yet possible to build a spacetime machine because we need materials — which we call exotic matter — to bend spacetime in these impossible ways and they have yet to be discovered."

The findings seemingly build on a talk Professor Brian Cox made in 2013 in which he said time travel is possible, but only when travelling to the future. "You can go into the future; you've got almost total freedom of movement in the future," but going back is impossible because "if you go fast, your clock runs slow relative to people who are still. As you approach the speed of light, your clock runs so slow you could come back 10,000 years in the future."

The theory is based on Einstein's Theory of Special Relatively that states to travel forward in time, an object would need to reach speeds close to the speed of light. As an object approach these speeds, time slows down but only for that specific object travelling.

The latest research is published in the journal Classical and Quantum Gravity .

This article was originally published by WIRED UK

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Physicist explains why time travel isn’t possible

You are free to share this article under the Attribution 4.0 International license.

A simple question from his wife—Does physics really allow people to travel back in time?—propelled physicist Richard Muller on a quest to resolve a fundamental problem that had puzzled him throughout his career: Why does the arrow of time flow inexorably toward the future, constantly creating new “nows?”

“The future does not yet exist … it is being created.”

That quest resulted in a new book called NOW: The Physics of Time (W. W. Norton, 2016), which delves into the history of philosophers’ and scientists’ concepts of time, uncovers a tendency physicists have to be vague about time’s passage, demolishes the popular explanation for the arrow of time,“ and proposes a totally new theory.

His idea: Time is expanding because space is expanding.

“The new physics principle is that space and time are linked; when you create new space, you will create new time,” says Muller, a professor emeritus of the University of California, Berkeley.

In commenting on the theory and Muller’s new book, astrophysicist Neil deGrasse Tyson, host of the 2014 TV miniseries Cosmos: A Spacetime Odyssey , writes, “Maybe it’s right. Maybe it’s wrong. But along the way he’s given you a master class in what time is and how and why we perceive it the way we do.”

How our brains create ‘mental time travel’

“Time has been a stumbling block to our understanding of the universe,” adds Muller. “Over my career, I’ve seen a lot of nonsense published about time, and I started thinking about it and realized I had a lot to say from having taught the subject over many decades, having thought about it, having been annoyed by it, having some really interesting ways of presenting it, and some whole new ideas that have never appeared in the literature.”

The origin of ‘now’

Ever since the Big Bang explosively set off the expansion of the universe 13.8 billion years ago, the cosmos has been growing, something physicists can measure as the Hubble expansion. They don’t think of it as stars flying away from one another, however, but as stars embedded in space and space continually expanding.

Muller takes his lead from Albert Einstein, who built his theory of general relativity—the theory that explains everything from black holes to cosmic evolution—on the idea of a four-dimensional spacetime. Space is not the only thing expanding, Muller says; spacetime is expanding. And we are surfing the crest of that wave, what we call “now.”

How far into the future are you still yourself?

“Every moment, the universe gets a little bigger, and there is a little more time, and it is this leading edge of time that we refer to as now,” he writes. “The future does not yet exist … it is being created. Now is at the boundary, the shock front, the new time that is coming from nothing, the leading edge of time.”

Because the future doesn’t yet exist, we can’t travel into the future, he asserts. He argues, too, that going back in time is equally improbable, since to reverse time you would have to decrease, at least locally, the amount of space in the universe. That does happen, such as when a star explodes or a black hole evaporates. But these reduce time so infinitesimally that the effect would be hidden in the quantum uncertainty of measurement—an instance of what physicists call cosmic censorship.

“The only example I could come up with is black hole evaporation, and in that case it turns out to be censored. So I couldn’t come up with any way to reverse time, and my basic conclusion is that time travel is not possible,” he says.

Merging black holes

Muller’s theory explaining the flow of time led to a collaboration with Caltech theoretician Shaun Maguire and a paper posted online in June that explains the theory in more detail—using mathematics—and proposes a way to test it using LIGO, an experiment that detects gravitational waves created by merging black holes.

“The idea of studying time itself did not exist prior to Einstein. Einstein gave physics the gift of time.”

If Muller and Maguire are right, then when two black holes merge and create new space, they should also create new time, which would delay the gravitational wave signal LIGO observes from Earth.

“The coalescing of two black holes creates millions of cubic miles of new space, which means a one-time creation of new time,” Muller says. The black hole merger first reported by LIGO in February 2016 involved two black holes weighing about 29 and 36 times the mass of the sun, producing a final black hole weighing about 62 solar masses. The new space created in the merger would produce about 1 millisecond of new time, which is near the detection level of LIGO. A similar event at one-third the distance would allow LIGO to detect the newly created time.

‘I expect controversy!’

Whether or not the theory pans out, Muller’s book makes a good case.

“[Muller] forges a new path. I expect controversy!” writes UC Berkeley Nobel laureate Saul Perlmutter, who garnered the 2011 Nobel Prize in Physics for discovering the accelerating expansion of the universe. Muller initiated the project that led to that discovery, which involved measuring the distances and velocities of supernovae. The implication of that discovery is that the progression of time is also accelerating, driven by dark energy.

For the book project, Muller explored previous explanations for the arrow of time and discovered that many philosophers and scientists have been flummoxed by the fact that we are always living in the “now:” from Aristotle and Augustine to Paul Dirac—the discoverer of antimatter, which can be thought of as normal matter moving backward in time—and Albert Einstein. While philosophers were not afraid to express an opinion, most physicists basically ignored the issue.

“No physics theories have the flow of time built into them in any way. Time was just the platform on which you did your calculations—there was no ‘now’ mentioned, no flow of time,” Muller says. “The idea of studying time itself did not exist prior to Einstein. Einstein gave physics the gift of time.”

Team detects ripples in spacetime, just as Einstein predicted

Einstein, however, was unable to explain the flow of time into the future instead of into the past, despite the fact that the theories of physics work equally well going forward or backward in time. And although he could calculate different rates of time, depending on velocity and gravity, he had no idea why time flowed at all. The dominant idea today for the direction of time came from Arthur Eddington, who helped validate Einstein’s general theory of relativity. Eddington put forward the idea that time flows in the direction of increasing disorder in the universe, or entropy. Because the Second Law of Thermodynamics asserts that entropy can never decrease, time always increases.

Was Stephen Hawking wrong?

This idea has been the go-to explanation since. Even Stephen Hawking, in his book A Brief History of Time , doesn’t address the issue of the flow of time, other than to say that it’s “self-evident” that increasing time comes from increasing entropy.

“I don’t see any way that it affects our everyday lives. But it is fascinating.”

Muller argues, however, that it is not self-evident: it is just wrong. Life and everything we do on Earth, whether building houses or making teacups, involves decreasing the local entropy, even though the total entropy of the universe increases. “We are constantly discarding excess entropy like garbage, throwing it off to infinity in the form of heat radiation,” Muller says. “The entropy of the universe does indeed go up, but the local entropy, the entropy of the Earth and life and civilization, is constantly decreasing.

“During my first big experiment, the measurement of the cosmic microwave radiation, I realized there is 10 million times more entropy in that radiation than there is in all of the mass of the universe, and it’s not changing with time. Yet time is progressing,” he says. “The idea that the arrow of time is set by entropy does not make any predictions, it is simply a statement of a correlation. And to claim it is causation makes no sense.”

In his book, Muller explains the various paradoxes that arise from the way the theories of relativity and quantum mechanics treat time, including the Schrodinger’s cat conundrum and spooky action at a distance that quantum entanglement allows. Neither of these theories addresses the flow of time, however. Theories about wormholes that can transport you across the universe or back in time are speculative and, in many cases, wrong.

The discussion eventually leads Muller to explore deep questions about the ability of the past to predict the future and what that says about the existence of free will.

Muller admits that his new theory about time may have observable effects only in the cosmic realm, such as our interpretation of the red shift—the stretching of light waves caused by the expansion of space—which would have to be modified to reflect the simultaneous expansion of time. The two effects may not be distinguishable throughout most of the universe’s history, but the creation of time might be discernible during the rapid cosmic inflation that took place just after the Big Bang, when space and time expanded much, much faster than today.

He is optimistic that in the next few years LIGO will verify or falsify his theory.

“I think my theory is going to have an impact on calculations of the very early universe,” Muller says. “I don’t see any way that it affects our everyday lives. But it is fascinating.”

Source: UC Berkeley

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Is Time Travel Actually Possible?

We all know how time travel works, right? You step into a gyroscopic chamber in a secret science research facility, a dude in a white lab coat hits a switch, the chamber spins and makes "bwa wa wa" sounds as arcs of blue "energy" crackle around, and snap: You're face-to-face with Arnold Schwarzenegger circa 200 million B.C.E. for a mission to shoot up dinosaurs with robo gun arms. Pew-pew!

Well, it's time to dash to pieces all of our beloved, sci-fi-conjured time travel visions from "Star Trek," "Back to the Future," "Avengers: Endgame," "The Terminator," and even classy, supposedly more grounded fare like "Interstellar." No, you won't be going back in time to chat up Julius Caesar in English, sire your own grandfather , or save humanity with the power of semi-clever plot contrivances. And yet, sites like Scientific American say that time travel is possible. What gives?

When physicists say that "time travel is possible," they mean that time passes differently for different observers based on speed and distance — i.e., "time is relative," ala Albert Einstein's  famed E = mc 2  theory of special relativity. They also mean that "there's nothing mathematically preventing time from moving in reverse." But we experience time unidirectionally because molecules tend to move from higher to lower states of order, as Quanta Magazine outlines — i.e., "Time's Arrow."  Putting these two together means: 1) No one refutes that forward-moving time travel is possible, and, 2) Backward-moving time travel is impossible.

Space, not time

It sounds like a perfectly typical, baseless, first-year philosophy student proclamation: "You see — time ... doesn't exist!" Cue the smoke bomb and rapturous facial expression. Well, it's time to blow everyone's minds and confirm that, yeah, that statement is kinda-sorta true. Except, it's only true because time isn't time. Time is space, which means time travel is really space travel.

In his 1905 theory of special relativity, Albert Einstein noted that as objects approach the speed of light , they experience time more slowly. As Live Science  overviews, this is referred to as "time dilation." But to that fast-moving object, everyone else is slow. Hence: Time is relative and not the same for all observers. 

Four years later in 1909, German mathematician Hermann Minkowski coined the term "space-time" to refer to the unified spatial and temporal nature of reality. Time, he concluded, is just another aspect — a dimension — of space. You can move through space at the expense of time, or vice-versa, like how you can turn right at the expense of turning left, per Big Think . To the perspective of light particles — the massless, fastest objects in the universe — time doesn't exist, as Forbes explains.

So, if you want to time travel? You've got to travel through space at near-lightspeed. And as the rest of reality zips by, you slow down. Presto: You're in the future. But you can't go back, as Live Science details. Past physical space no longer exists.

Forward, not backward

"You can never go home again," the somewhat cryptic statement goes. But while that statement refers to an inability to recapture the magical fancies of youth, it could also just as easily refer to time travel. 

"Why can't you travel backward in time?" the somewhat consternated headline on Ars Technica asks. Well, because the past doesn't exist in any physical sense with which we could ever interact. It's a psychological construct composed of memories that don't live outside of your head — sorry. The only place the "past" exists is in the far reaches of telescopic sight, like when the James Webb Space Telescope  sees light from the early universe that's just reaching us now. In that moment, we're viewing the remote past.

When considering why we can't travel backward in time, we really have to ask, "Why can't molecules spontaneously rearrange themselves into former compositions?" If that happened, then a cracked egg would reform, or spilled milk would slide back up into a glass. But as the second law of thermodynamics says, entropy in a closed system must always increase. Entropy is the tendency for the arrangement of molecules to grow evermore disordered over time, and the universe is a closed system because nothing exists outside of it. And as Popular Mechanics overviews, entropy has continued to increase since the formation of the cosmos. There's simply no way to slip into any previous molecular arrangement, because remember: Time isn't time. Time is space.

Hitching on a ride with the black hole express

There's one viable time travel method on which physicists can agree: Hitching a ride with a black hole . Or more specifically: Moving past its outer, spinning accretion disc and toward the central event horizon from which nothing can escape. As described by  Royal Museums Greenwich , this process will most certainly kill you by "spaghettifying" your body. So once again, we're talking about a one-way trip. 

Remember we said that as you approach the speed of light, time dilates, i.e., slows down? Well, black holes spin at near-light speed. This is something that one movie — "Interstellar"  — got right. But no, you won't get sucked into a 4D library to push some books off of Murph's bookshelf (it's complicated — watch the movie). As Astronomy says, a person stuck in the event horizon of a black hole would observe the rest of the universe aging much faster. That person, strictly speaking, would be in "the future." Now, if we could escape from a black hole? We'd have a workable solution for future-bound time travel.

And yet, as The Conversation reports, some researchers believe black holes can do the impossible: Send someone backward in time. If a celestial object was so massive that it "dragged" spacetime with it, it could create a closed timelike curve (CTC) that could pull someone into "the past." Still, folks like renowned physicist Stephen Hawking thought this was nonsense.

Feasibly impossible

There are a couple of other weird addendums to the "Is time travel possible?" discussion. Chiefly, as physicist Sabine Hossenfelder says on her YouTube channel: "You need a receiver station for time travel." This is something fictional time travel always leaves out and gets wrong. Earth isn't sitting in space like a stone on the ground. As Scientific American says, it's rotating at about 1,000 miles per hour while revolving around the sun at 67,000 miles per hour. On top of this, our entire solar system is spinning through the Milky Way at 490,000 miles per hour. So if you time traveled just one second forward or backward, but didn't account for planetary motion? You'd teleport right into empty space. And so, like we've said: Time travel is space travel .

And finally, there's quantum entanglement : That thing that you've heard about that no one understands. Quanta Magazine explains how quantum entanglement — the codependence of molecular attributes over distances — gives rise to time's arrow. We'll save you the headache by saying: If it was possible to manipulate the attributes of individual atoms, we could reconstruct "the past." This, however, is whackadoodle fantasy absurdity that necessitates digging into further and further realms of unfounded speculation.

So, is time travel possible? Mathematically, yes. Forward, yes. Backward, no. But is it feasible? Let's put it this way: Best focus on the present, because by the time humanity untangles time travel, our present will be nothing but the memory of entropy's future. 

Is time travel even possible? An astrophysicist explains the science behind the science fiction

Published: Nov 13, 2023

By: Magazine Editor

Written by Adi Foord , assistant professor of physics , UMBC

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to [email protected] .

Will it ever be possible for time travel to occur? – Alana C., age 12, Queens, New York

Have you ever dreamed of traveling through time, like characters do in science fiction movies? For centuries, the concept of time travel has captivated people’s imaginations. Time travel is the concept of moving between different points in time, just like you move between different places. In movies, you might have seen characters using special machines, magical devices or even hopping into a futuristic car to travel backward or forward in time.

But is this just a fun idea for movies, or could it really happen?

The question of whether time is reversible remains one of the biggest unresolved questions in science. If the universe follows the laws of thermodynamics , it may not be possible. The second law of thermodynamics states that things in the universe can either remain the same or become more disordered over time.

It’s a bit like saying you can’t unscramble eggs once they’ve been cooked. According to this law, the universe can never go back exactly to how it was before. Time can only go forward, like a one-way street.

Time is relative

However, physicist Albert Einstein’s theory of special relativity suggests that time passes at different rates for different people. Someone speeding along on a spaceship moving close to the speed of light – 671 million miles per hour! – will experience time slower than a person on Earth.

People have yet to build spaceships that can move at speeds anywhere near as fast as light, but astronauts who visit the International Space Station orbit around the Earth at speeds close to 17,500 mph. Astronaut Scott Kelly has spent 520 days at the International Space Station, and as a result has aged a little more slowly than his twin brother – and fellow astronaut – Mark Kelly. Scott used to be 6 minutes younger than his twin brother. Now, because Scott was traveling so much faster than Mark and for so many days, he is 6 minutes and 5 milliseconds younger .

Some scientists are exploring other ideas that could theoretically allow time travel. One concept involves wormholes , or hypothetical tunnels in space that could create shortcuts for journeys across the universe. If someone could build a wormhole and then figure out a way to move one end at close to the speed of light – like the hypothetical spaceship mentioned above – the moving end would age more slowly than the stationary end. Someone who entered the moving end and exited the wormhole through the stationary end would come out in their past.

However, wormholes remain theoretical: Scientists have yet to spot one. It also looks like it would be incredibly challenging to send humans through a wormhole space tunnel.

Paradoxes and failed dinner parties

There are also paradoxes associated with time travel. The famous “ grandfather paradox ” is a hypothetical problem that could arise if someone traveled back in time and accidentally prevented their grandparents from meeting. This would create a paradox where you were never born, which raises the question: How could you have traveled back in time in the first place? It’s a mind-boggling puzzle that adds to the mystery of time travel.

Famously, physicist Stephen Hawking tested the possibility of time travel by throwing a dinner party where invitations noting the date, time and coordinates were not sent out until after it had happened. His hope was that his invitation would be read by someone living in the future, who had capabilities to travel back in time. But no one showed up.

As he pointed out : “The best evidence we have that time travel is not possible, and never will be, is that we have not been invaded by hordes of tourists from the future.”

Telescopes are time machines

Interestingly, astrophysicists armed with powerful telescopes possess a unique form of time travel. As they peer into the vast expanse of the cosmos, they gaze into the past universe. Light from all galaxies and stars takes time to travel, and these beams of light carry information from the distant past. When astrophysicists observe a star or a galaxy through a telescope, they are not seeing it as it is in the present, but as it existed when the light began its journey to Earth millions to billions of years ago. https://www.youtube.com/embed/QeRtcJi3V38?wmode=transparent&start=0 Telescopes are a kind of time machine – they let you peer into the past.

NASA’s newest space telescope, the James Webb Space Telescope , is peering at galaxies that were formed at the very beginning of the Big Bang, about 13.7 billion years ago.

While we aren’t likely to have time machines like the ones in movies anytime soon, scientists are actively researching and exploring new ideas. But for now, we’ll have to enjoy the idea of time travel in our favorite books, movies and dreams.

This article is republished from The Conversation under a Creative Commons license. Read the original article and see more than 250 UMBC articles available in The Conversation.

Tags: CNMS , Physics , The Conversation

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Science News

Can time travel survive a theory of everything.

It’s complicated. But studying ways to visit the past could help us understand the cosmos

By Tom Siegfried

Contributing Correspondent

September 20, 2019 at 8:00 am

The TARDIS and other fictional time machines make time travel look relatively easy (Peter Capaldi and Jenna Coleman are shown promoting the BBC’s Doctor Who ). But just because it’s permitted by the laws of physics, doesn’t mean it’s practical.

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In many universes, typically those on TV shows or in movies, time travel is not much more difficult than driving downtown in any major city during rush hour. Sure, the traffic can get gnarly, but no law of physics prevents you from reaching your destination eventually.

In real life, time travel isn’t so easy. In fact, it’s probably impossible, a fantasy more farfetched than visiting Alice’s Wonderland, finding gold at the end of a rainbow or cleansing all the hate speech off of Facebook.

Yet time travel does not necessarily violate the laws of physics. In Einstein’s theory of gravity — general relativity — space and time are merged as spacetime, which allows for the possibility of pathways that could bend back to the past and loop back to the future.

Such paths are known as closed timelike curves. They’re a little like great circles around the surface of the Earth — if you start out in one direction and keep going straight, eventually you come back to where you started from. In that case the Earth’s curvature guides you back to your previous point in space; with closed timelike curves, the geometry of spacetime guides you back to an earlier moment in time.

Nobody thinks that general relativity’s time loops would be practical for time travel even if they are possible. For one thing, they might exist only under certain circumstances — the universe would have to be rotating, and not expanding — as the mathematician Kurt Gödel showed in the 1940s. But the universe is expanding, and probably isn’t rotating, so that dampens the prospects for revisiting the Stone Age or acquiring a pet dinosaur.

Besides, even if such pathways did exist, building a ship to traverse them would cost more than all the DeLoreans (and all other transportation vehicles) ever made. It would need a cruising speed of 140,000 miles per second. And with no place to stop for gas (or whatever), the fuel tank would have to be more than a trillion times the size of an oil tanker.

So for practical purposes, time travel’s time has not yet arrived. But even if it’s possible only in principle, the potential ramifications for the basic physics of the universe might make it worth the time to investigate it. Time loops might not enable you to traverse the cosmos in a TARDIS, but perhaps could still help you understand the cosmos more deeply.

A first step would be to attempt to figure out exactly what the relevant laws of physics really are. Einstein’s general relativity is great, but indubitably not the last word about the physics of the universe. After all, it coexists uneasily with quantum mechanics, which rules the subatomic world and presumably, since everything is made of subatomic stuff, the rest of the universe as well. Whether the quantum–general relativity combo truly permits time travel might depend on what the ultimate correct theory combining the two turns out to be.

Several candidate theories have been developed for merging general relativity and quantum mechanics into a unified theory. It’s an open question whether these candidates would allow time travel in something like the way general relativity does, philosopher Christian Wüthrich of the University of Geneva notes in a new paper.

It’s possible, he says, that a theory that supersedes general relativity might still in some way include the equivalent of general relativity’s timelike loops. And even if the basic theory does not include such loops, they still might emerge in practice.

“Although the fundamental theory would then remain inhospitable to time travel itself, it would tolerate the possibility of time travel at some other, less fundamental, scale,” Wüthrich writes in his paper , posted online in June. “Depending on what the relationship between the fundamental theory and emergent spacetime may be in each case, we may find that the emergent, macroscopic spacetime structure permits time travel.”

Reviewing the major proposals for quantum gravity theories does not provide a lot of hope, though. One approach, known as causal set theory, requires sets of events to be ordered in a proper cause-and-effect relationship. So its central idea seems to rule out closed timelike curves.

Another popular approach, known as loop quantum gravity, envisions space to be constructed of fundamental loops (kind of like “atoms of space”). This view has encountered technical difficulties, one of which is how to work time into the picture with space. “Thus, we seem to be faced with a temporally innocuous structure in which no meaningful sense of time travel is permitted,” Wüthrich writes.

It’s possible that the networks of these “atoms of space” could produce high-level spacetime that did contain closed timelike curves. But analysis of the details at this stage of loop quantum gravity’s development does not offer much reason for optimism, Wüthrich concludes.

Time travel’s future might look a little brighter if the correct approach to quantum gravity turns out to be string theory, currently the most popular contender. In string theory, matter’s basic particles are tiny vibrating snippets of energy, called “strings” because they extend in one dimension. Multiple versions of string theory have been constructed, suggesting that they are different manifestations of a more fundamental master theory known as M-theory.

“As M-theory does not yet exist, it is impossible to determine its verdict on time travel,” writes Wüthrich. But investigations of various string theory scenarios do suggest that the ultimate theory would, in fact, naturally incorporate closed timelike curves.

Even if time loops exist in the fundamental theory, though, there’s still no guarantee that they would be preserved in the emergent large-scale spacetime that would be relevant in real life. For that matter, Wüthrich points out, predicting the existence of time travel loops might be taken as evidence against the theory, considering the serious likelihood that time travel really isn’t possible at all.

So whether general relativity’s time loops will survive in a deeper theory remains an open question. “A more fundamental theory may well admit structures amounting to closed timelike curves and thus permit time travel,” Wüthrich asserts. “This clearly remains a live option at the present stage of knowledge.”

In any case, investigating whether quantum gravity theories retain general relativity’s time travel loophole can illuminate many tough questions that must be answered to develop a successful theory and understand how it relates to general relativity. “For this reason alone,” Wüthrich writes, “the question of time travel beyond general relativity is worth our while.”

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Astrophysicist says he has cracked the code for time travel

Can you imagine going back in time to visit a lost loved one? This heartwrenching desire is what propelled astrophysicist Professor Ron Mallett on a lifelong quest to build a time machine. After years of research, Professor Mallett claims to have finally developed the revolutionary equation for time travel.

The idea of bending time to our will – revisiting the past, altering history, or glimpsing into the future – has been a staple of science fiction for over a century. But could it move from fantasy to reality?

The inspiration: A father’s love and a classic novel

Professor Mallett’s obsession with time travel and its equation has its roots in a shattering childhood experience. When he was just ten years old, his father, a television repairman who fostered his son’s love of science, tragically passed away from a heart attack.

Devastated, the young Mallett sought solace in books. It was H.G. Wells’ The Time Machine that sparked a lifelong fascination.

Wells’ opening lines became his mantra: “Scientific people know very well that Time is only a kind of Space. And why cannot we move in Time as we move about in the other dimensions of Space?”

This profound question ignited Mallett’s scientific journey. He dedicated himself to understanding the nature of time, determined to find a way to revisit the past and see his beloved father once more.

Time travel equation in the hospital

Decades of research into black holes and Einstein’s theories of relativity led to the time travel equation.

While hospitalized for a heart condition, Mallett had a revelation. “It turns out that black holes can create a gravitational field that could lead to the creation of time loops that could allow us to go back in time,” he explained.

Imagine the fabric of spacetime as a river. While time usually flows in one direction, Mallett theorizes that the immense gravity of a spinning black hole can create whirlpools, where time twists back on itself.

The time machine blueprint

Mallett’s vision for a time machine centers on what he calls “an intense and continuous rotating beam of light” to manipulate gravity. His device would use a ring of lasers to mimic the spacetime-distorting effects of a black hole.

“Let’s say you have a cup of coffee in front of you. Start stirring the coffee with the spoon. It started to spin, right? That’s what a spinning black hole does,” explained Mallett.

“In Einstein’s theory, space and time are related to each other. That’s why it’s called space-time. So when the black hole spins, it will actually cause time to shift.”

“Eventually, a rotating beam of laser lights can be used as a kind of time machine and cause a time warp that will allow us to go back to the past,” said Mallett. Perhaps, what began as a son’s wish to see his father one last time might one day transform our understanding of time itself.

Challenges and limitations

The obstacles on the path from time travel equation to machine are immense. Mallett acknowledges the “galactic amounts of energy” needed to power such a device – energy levels far beyond our current capabilities.

The sheer size of a theoretical time machine is also unknown. While Mallett optimistically states, “I figured out how to do it. In theory, it is possible,” the reality is that he may not live to see the machine built.

Furthermore, Mallett’s theory comes with a significant constraint. “You can send information back, but you can only send it back to the point where you started operating the device.”

In this sense, the time machine is like a one-way message service to the past. You can’t travel to a point before the machine existed.

Mallet’s lifetime of dedication to time travel

Despite the daunting challenges, Mallett’s remarkable journey is a testament to the human spirit. Alongside his time travel research, he’s led a distinguished academic career, teaching physics at the University of Connecticut .

Now in his seventies, his work has been propelled by an unwavering belief in the possibility of the seemingly impossible.

Equation vs. reality of time travel

Whether Mallett’s time machine will ever transcend the realm of theory is uncertain. Skeptics point to the vast technological hurdles and potential paradoxes raised by tampering with time.

Yet, the mere possibility that science might one day unlock the secrets of temporal travel is enough to ignite the imagination. Could we rewrite our regrets, learn from past mistakes, or witness historical events firsthand?

Perhaps Professor Mallett’s greatest legacy won’t be a time travel equation itself, but the inspiration he provides – a reminder that audacious dreams and unrelenting curiosity have the power to push the boundaries of what we believe is possible.

Read more about Professor Mallett’s work here .

More about space-time

As discussed above, space-time, a concept that feels as vast and complex as the universe itself, forms the backbone of our cosmic understanding.

At its core, it blends the dimensions of space and time into a single four-dimensional continuum, challenging our perceptions of reality. This intertwined nature of space and time underpins everything from the motion of planets to the flow of time itself.

Einstein’s groundbreaking contribution

Albert Einstein, with his theory of relativity, revolutionized our understanding of space-time. He posited that space and time are not separate entities but are connected in a dynamic relationship affected by mass and energy.

This relationship implies that the presence of a massive object, like a planet or a star, can warp the fabric of space-time around it. It’s a concept that turns the notion of a flat, unchanging universe on its head, suggesting that the very structure of the cosmos is malleable.

The warp and weft of the cosmos

Imagine space-time as a vast sheet of fabric. When a heavy object sits on this fabric, it creates a dip or curve. This curvature is what we perceive as gravity.

Planets orbit stars not because they are being “pulled” in a straight line towards them, but because they are following the curved space-time geometry that these massive objects create.

This curvature of space-time is not just a theoretical concept; it’s observable and measurable, especially in the presence of extremely massive and dense objects, like black holes.

Gravitational waves: Echoes of cosmic events

One of the most compelling pieces of evidence for the theory of relativity and the dynamic nature of space-time comes from the detection of gravitational waves.

These waves are ripples in the fabric of space-time, generated by some of the most violent and energetic processes in the universe, such as colliding black holes.

Their discovery not only confirmed Einstein’s predictions but also opened a new window into observing cosmic events that were previously invisible to us.

Practical impact of space-time

While these concepts might seem distant from daily life, they have real-world applications, particularly in technology. The Global Positioning System (GPS), a technology integral to modern navigation, relies on an understanding of space-time.

Satellites orbiting Earth need to account for the effects of gravitational time dilation — a consequence of the curvature of space-time — to provide accurate location data to users on the ground.

In summary, space-time is a framework that shapes our understanding of the universe. From guiding the planets in their orbits to enabling precise navigation on Earth, its effects are both profoundly cosmic and surprisingly practical.

As we continue to explore and understand the intricacies of space-time, we edge closer to unraveling the mysteries of the cosmos, one gravitational wave at a time.

How black holes are linked to time travel

Playing a major role in Dr. Mallett’s time machine, black holes exert a gravitational pull so immense that not even light can escape their grasp. This intense gravity fundamentally alters the fabric of space-time around the black hole.

The stronger the gravity, the more pronounced these effects become, leading to what scientists call gravitational time dilation — a phenomenon where time itself warps, slowing down relative to an observer far from the gravitational pull.

Time dilation explained

At the heart of this phenomenon lies Albert Einstein’s theory of General Relativity, which posits that gravity is the result of masses warping the space-time around them.

In the vicinity of a black hole, this warping becomes so extreme that it significantly affects the flow of time.

An observer standing at a safe distance would perceive time to pass much slower for someone closer to the black hole.

This effect intensifies as one approaches the event horizon, the point of no return beyond which the gravitational pull becomes inescapable.

Boundary between time zones

The event horizon of a black hole marks a stark boundary in the universe, where time as we understand it undergoes a dramatic transformation.

To an external observer, objects approaching the event horizon appear to slow down and almost freeze in time, never quite crossing the threshold.

This illusion results from the light from those objects taking longer and longer to reach the observer as the objects move closer to the event horizon, due to the extreme gravitational pull affecting the light’s path.

Theoretical implications and observations

This warping of time around black holes is not just a theoretical curiosity. As Dr. Mallett explained previously in this article, it has practical implications for our understanding of the universe. For instance, it plays a crucial role in the behavior of binary systems where one star orbits a black hole.

Moreover, advancements in technology, such as precise atomic clocks and observations from space telescopes, have allowed scientists to measure these effects, further confirming the predictions of General Relativity.

In summary, black holes serve as natural laboratories for testing the limits of our understanding of physics, offering insights into the complex interplay between gravity and the fabric of space-time.

The phenomenon of time dilation near these cosmic behemoths challenges our notions of time and space, inviting us to explore beyond the boundaries of our current knowledge.

As we continue to observe and study these fascinating objects, we inch closer to unraveling the mysteries of the universe.

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Time Travel: Dream or Possible Reality?

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Time travel is a favorite plot device in science fiction stories and movies. Perhaps the most famous recent series is Dr. Who , with its traveling Time Lords who whisk throughout time as if traveling by jet. In other stories, the time travel is due to unexplainable circumstances such as a too-close approach to a very massive object like a black hole. In Star Trek: The Voyage Home , the plot device was a trip around the Sun that hurled Kirk and Spock back to 20th century Earth. In the popular movie series Back to the Future , the characters traveled both backward and forward in time. However it is described in stories, traveling through time seems to pique people's interest and ignite their imaginations. But, is such a thing possible? 

The Nature of Time

It's important to remember that we are always traveling into the future. That's the nature of space-time. This is why we remember the past (instead of "remembering" the future). The future is largely unpredictable because it hasn't happened yet, but everyone is headed into it all the time.

To speed up the process, to peer further into the future, to experience events more quickly than those around us, what would or could anyone do to make it happen? It's a good question without a definitive answer. Right now, no one has built a working time machine to travel temporally.

Traveling into the Future

While it's not possible (yet) to travel to the future fast than the rate at which we're doing it now, it is possible to speed up the passage of time. But, it only happens in small increments of time. And, it has only happened (so far) to very few people who have traveled off Earth's surface. For them, time moves at an infinitesimally different rate. Could it happen over longer time spans? 

It might, theoretically. According to Einstein's theory of special relativity , the passage of time is relative to an object's speed. The more quickly an object moves through space, the more slowly time passes for it compared to an observer traveling at a slower pace. 

The classic example of traveling into the future is the twin paradox . It works like this: take a pair of twins, each 20 years old. They live on Earth. One takes off on a spaceship on a five-year journey traveling at nearly the speed of light . The traveling twin ages five years while on the journey and returns to Earth at the age of 25. However, the twin who stayed behind is 95 years old! The twin on the ship experienced only five years of time passing, but returns to an Earth that is much farther into the future.

Using Gravity as a Means of Time Travel

In much the same way that traveling at speeds close to the speed of light can slow down perceived time, intense gravitational fields can have the same effect.

Gravity only affects the movement of space, but also the flow of time. Time passes more slowly for an observer inside a massive object's gravitational well. The stronger the gravity, the more it affects the flow of time. 

Astronauts on the  International Space Station experience a combination of these effects, though on a much smaller scale. Since they are traveling quite quickly and orbiting around Earth (a massive body with significant gravity), time slows down for them compared to people on Earth. The difference is much less than a second over the course of their time in space. But, it is measurable.

Could We Ever Travel into the Future?

Until we can figure out a way to approach the speed of light (and warp drive doesn't count , not that we know how to do that at this point, either), or travel near black holes (or travel to black holes for that matter) without falling in, we won't be able to do time travel any significant way into the future. 

Travel into the Past

Moving into the past is also impossible given our current technology. If it were possible, some peculiar effects could occur. These include the famous "go back in time and kill your grandfather" paradox. If you did do it, you couldn't do it, because you already killed him, so therefore you don't exist and can't go back in time to do the dastardly deed. Confusing, isn't it? 

Key Takeaways

• Time travel is a science fiction trope that may possibly be technically possible. But, no one has achieved it.
• We do travel into the future all our lives, at a second per second. To do it faster requires technology we don't have.
• Travel to the past is also impossible at the present time.
• Is Time Travel Possible?| Explore , www.physics.org/article-questions.asp?id=131.
• NASA , NASA, spaceplace.nasa.gov/review/dr-marc-space/time-travel.html.
• “Time Travel.”  TV Tropes , tvtropes.org/pmwiki/pmwiki.php/Main/TimeTravel.

Edited by Carolyn Collins Petersen .

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