Bringing back the good times or preventing something bad from happening can be a wish for many. It would be great if it was possible inTime MachineLike ‘Back to the Future.’ But according to science, though time travel Possibly, not happening the way we imagine.
Albert Einstein, more than 100 years ago, wrote the famous Theory of relativity. According to her, time and space are linked and nothing can travel faster than the speed of light, which is 299.337984 kilometers per second.
to me time travelThis means that the faster the travel, the slower the time. Time, according to Einstein, would be an illusion moving relative to an observer. This difference in how time is perceived is calledtime dilation“.
An experiment using two hours at the same time clarifies this theory well. One remained on the ground and the other was flying in an airplane (in the same direction as the Earth rotates). After the plane flew around the world, the two watches were compared, and their times differed. The moving plane was a little later than the one that was on the “land”.
The explanation for this may be that the clock of the plane, which was moving faster in space, was traveling slowly in time. The theory of relativity also explains why astronaut Scott Kelly has been in orbit for a year less than his twin brother who stayed on Earth.
While this difference may lead to jokes between siblings rather than years of age, it is possible to compare the difference that Earth orbit makes in an astronaut’s life. When we measure the time we experience on Earth and the time of GPS satellites flying through space, there are big differences.
GPS satellites with atomic clocks have seven microseconds — or seven millionths of a second — fewer every day, according to a publication from the American Physics Society.
This type of mismatch reveals a kind of time travel They differ from the way we know them, which may be seemingly unrelated, but when we consider long periods of time, the difference can be quite impressive.
If Einstein’s explanation does not sound very encouraging, know that there are other theories beside it, which would allow a jump forward or backward in time.
This is the case of Frank Tippler, who proposes rotating a cylinder with ten times the mass of the Sun for a few billion revolutions per minute, which would make us “go back in time.” But there’s a drawback: We won’t survive the kind of gravity required to do so.
Amos Ori of the Israeli Technion Institute of Technology in Haifa, Israel has also proposed a time machine model. It would be made of curved spacetime (i.e. a doughnut-shaped space surrounded by a circle of matter). For him, “the machine is space-time itself”.
“If we create an area with a flexion like this in space that would allow timelines to close, that would allow future generations to come back to visit our time,” Urey says.
Urey’s theory converges with what Anna Alonso Serrano, a postdoctoral researcher at the Max Planck Institute for Gravitational Physics in Germany, explains. As she told USA Today, “The moment you sculpt spacetime, you can play with that curvature to make time come in a circle and make a time machine.”
But just like Tepler’s theory, there are many flaws with this theory. Time travelers cannot travel back to before the creation of the “machine”. Even worse: building such a machine would depend on our ability to manipulate gravitational fields—something that might be possible in theory, but in practice, it’s still a long way from us.
There is also the theory of Einstein’s “wormhole” and the American-Israeli physicist Nathan Rosen. For them, the singularity is at the center of black holes, the point at which all matter is compressed to zero volume, and thus infinite density. This is called the Einstein-Rosen bridge, the official name for wormholes, which has not been discovered in practice.
But in 2019, a team of scientists from Stanford University put forward the thesis that this would not be possible, because it would be a very slow journey. “It will take longer to pass through these wormholes than to go directly to the expected destination,” commented Daniel Javris, one of the researchers.
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