It’s just a matter of time before we build something that can take us into the distant future.
In September 2015, cosmonaut Gennady Padalka returned to Earth for the last time. It has just completed its sixth mission in space and has broken the record for the total time spent outside Earth’s atmosphere: 879 days. And because of those 2.5 years orbiting the planet at high speeds, Padalka also became a time traveler, testing Einstein’s theory of general relativity in action.
“When Mr. Padalka returned, he found the Earth was 1 / 44th of a second in the future,” explains J. Richard Gott, Princeton physicist and author of Time Travel in Einstein’s Universe. “He literally traveled … into the future. “. Being a fraction of a second younger than if he had stayed on Earth is not incredible, nevertheless it gave Padalka the title of “current time traveler’s record,” according to Gott.
While not quite a plutonium-loaded DeLorean, time travel is anything but fiction. Real astrophysicists like Gott are pretty sure they know how to build a time machine, and high speed – much, much faster than Padalka’s orbital flight – is a key ingredient.
Time Travel Crash Course
Until the twentieth century, time was considered absolutely immutable, and time travel – scientific impossible. In the 1680s, Sir Isaac Newton’s mental time evolved at a constant pace throughout the universe, regardless of external forces or location. And for two centuries, the scientific world supported Newton’s theory.
Until 26-year-old Albert Einstein showed up.
In 1905, Einstein revealed his ideas on special relativity, using that framework for his theory of general relativity ten years later. Einstein’s calculations defining the universe introduced many things, as well as some concepts related to time. The most important thing is that time is elastic and depends on speed, slows down or accelerates depending on how fast an object or person is moving.
In 1971, four atomic cesium beam flew around the world, and then they were compared to a ground clock. As a result, a tiny difference in time proved that Einstein had stumbled upon something. There is another technology hidden inside your smartphone that also confirms Einstein’s theory…
Without Einstein’s theory of general relativity, GPS won’t work.
“Without Einstein’s theory of general relativity, our GPS system won’t work,” says Ron Mallett, astrophysicist and author of Time Traveler: A Scientist’s Personal Mission to Make Time Travel a Reality. It is also proof that Einstein’s theories are correct. “
But apart from this shifting version of time, Einstein also calculated the speed of light. Einstein describes the speed of 300,000,000 meters (or 186,282 miles) per second as a “speed limit” and a universal constant, whether a person is sitting on a bench or traveling in a rocket ship.
The last part of Einstein’s ideas about the warping of time suggests that gravity also slows down time, that is, time passes faster where gravity is weaker, for example, in a huge void among massive celestial bodies such as the Sun, Jupiter and Earth.
Fast forward a century, when all of these theories – highly generalized, of course – form the building blocks of astrophysics and are buried among all this expert-level mathematics. Einstein also proved that time travel is possible.
Subatomic time machine
In fact, time travel is not only possible, it has already happened, but it just doesn’t look like a typical sci-fi movie.
Going back to our time-traveling astronaut Padalka, his 1/44-second leap into the future is so paltry because he was traveling at just 17,000 miles per hour. It’s not very fast, at least compared to the speed of light. But what happens if we create something that can move much faster than in geostationary orbit? We are not talking about a commercial liner (550-600 miles per hour) or a 21st century rocket flying to the ISS (25,000 miles per hour), but about something that can get closer to 186,282 miles per second.
“At the subatomic level, this has already happened,” says Mallett. – An example is … the Large Hadron Collider. He regularly sends subatomic particles into the future. “
The particle accelerator is capable of moving protons at 99.999999 percent of the speed of light, the speed at which their relative time travels about 6900 times slower than the time of their stationary observers, humans.
So yes, we have sent atoms into the future, and we have been doing this for the last decade, but humans are a different matter.
Gott explains that given that we regularly accelerate particles to near the speed of light, conceptually it is fairly easy for humans to travel back in time to the future. “If you want to visit Earth in 3000,” says Gott, “all you have to do is board a spaceship and fly at 99.995 percent the speed of light.”
Let’s say a person is put on such a ship and sent to a planet that is a little less than 500 light years away (for example, Kepler 186f), that is, if it traveled at 99.995% of the speed of light, it would take 500 years to get there, since the ship travels at almost the speed of light.
After a quick snack and a break in the bathroom, they turned around and headed back to Earth, which took another 500 years. Thus, in total, it takes about a thousand years to return home safely. On Earth, it will be 3018.
However, because the ship was moving so fast, the resulting time dilation could not have seemed to them a thousand years from the moment their internal clock slowed down. “[Их] the clock will count down to 1/100 of the speed of the clock on Earth. It will only take them 10 years, ”says Gott. A millennium will pass for us, it will be a decade for them.
“If we [на Земле] looked out the window, they would have breakfast very slowly, says Gott, while for [них] everything would be fine. “
But there is a huge gap between the theoretical and the real. So how do we overcome the huge technological challenges of creating a time machine?
The not so distant future of time travel
The Parker Solar Probe will reach 430,000 mph – fast, but far from the speed of light.
Building a time-traveling spacecraft may be a better place to start, but the engineering hurdles, at least for now, are formidable. First, we are not even close to a spacecraft that can travel at the speed of light. The fastest spaceship ever built will soon be Parker Solar Probewhich will be launched this summer and will move only 0.00067% of the speed of light…
It also takes a tremendous amount of energy to get the ship to move that fast. Gott suggests that the key element could be high performance antimatter fuel, and other world agencies and scientists also believe that such fuel could become a potentially invaluable element of interstellar travel.
But ensuring the safety of human cargo in such a futuristic mission will also be difficult. Above all, the ship must have enough supplies such as food, water and medicine, and be self-sufficient throughout the journey.
Then there is everything to do with acceleration. To ensure that our hypothetical traveler is not destroyed by overwhelming G-forces, the ship must accelerate gradually and steadily. Although constant acceleration of 1g (similar to what we experience on Earth) over a long period will ultimately cause the ship to approach near the speed of light, it will increase the duration of the flight and minimize how far one can go in future.
Backward motion problem
But this theoretical portrait of real time travel has one big drawback – this machine does not reverse. While Bill and Ted travel back in time to meet Socrates, in reality, scientists and researchers need to find a way around the laws of physics in order to travel back in time.
Wormholes, black holes, cosmic strings and swirling light beams have been proposed as potential solutions to the problem of time travel in the past. The main challenge facing astrophysicists is figuring out how to direct a beam of light to and from a point in spacetime.
“Technology is around the corner … We could do it in the next 20 years.”
Since the speed of light is the absolute maximum, physicists are concentrating on detecting phenomena such as wormholes, which can provide a fast path through tunnels in which we jump through curved spacetime, and theoretically direct a beam of light to a specific point in spacetime.
While wormholes do work within Einstein’s theories of relativity, they have yet to be observed in space, and scientists have no concrete evidence that these galactic pathways will work.
So while traveling to the past may be a more exciting concept, scientists are much more likely to send someone to an unknown future rather than the past. But despite the huge odds (financial and scientific), Mallett believes that the future of the time travel society is possible.
“What happened to the flight to the moon… we wanted to go there, Kennedy asked for it, and there was proper funding, so we got to the moon,” says Mallett. “Technology is around the corner. If the government and taxpayers want to pay for it, we can do it in the next twenty years. ”
Today, time travel enthusiasts will still have to turn to science fiction for a time travel solution, with some films being much more accurate than others.
“Good movie … Planet of the Apes,” says Mallett. The astronauts thought they had landed on another planet ruled by monkeys, but it turned out they were traveling so fast that they arrived in the future of Earth. This film accurately describes Einstein’s special theory of relativity. ” Oh … spoilers.
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