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| Time travel may be theoretically possible, but it is beyond our current technological capabilities. |
How would you wish to go back to the future in a DeLorean car? Or travel with the crew of the USS Enterprise to avoid wasting the whales? These two examples (from "Back to the Future" and "Star Trek IV: The Voyage Home") show a very common image in science fiction — time travel.
We all have things we regret in life, so the idea of turning back time (or within the case of one "Superman" film, reversing Earth's rotation) is a tempting one. who would not wish to fix the past, or erase an unfortunate historical event that negatively impacted humanity? Or for those who are more centred on the future, however regarding turning time forward to check a neat event — such as the first human landing on Mars?
As one scientist points out, we have a tendency to all perpetually time travel — however, it's in exactly one direction. We're inevitably moving one second at a time into the future, {and we|and that we} may go quicker if we needed.
"Indeed, we are able to jump forward into the future as much as we wish. It's solely a matter of going extremely, extremely fast," Paul Sutter, an astronomer at Ohio State University, told Space.com in an email. He began by citing proof from Albert Einstein's theory of special relativity, that shows that time is relative depending on how fast you're moving.
"The quicker you move through space, the slower you progress through time. We've been able to measure this with ultra-precise atomic clocks in jet aeroplanes, and therefore the precision offered by the GPS system has to take this into consideration. Sci-fi continually appears to need sophisticated contraptions to leap in time, when all you need is a terribly massive rocket," Sutter wrote.
This means that astronauts, let's say, are already time travellers of a kind. that's as a result of they are going into space and continue to exist the International space station, generally for months at a time. At a speed of regarding five miles (8 kilometres) a second, astronauts on the space station are moving quicker than we are on Earth. this suggests that on the station, astronauts age just a little bit slower than they might on the planet's surface. (And that when astronaut Scott Kelly came back from a year in space, the age gap together with his slightly older twin, Mark, widened by just a little bit.)
But several sci-fi franchises concentrate on time travel to the past. Such travel raises neat queries, like whether or not you'll be able to return in time and kill your own grandparent (a puzzle generally said as "the grandfather paradox").
Sutter identified that the physics of our universe seem to forbid this case, at least as far as we are able to see. however surprisingly, a number of Einstein's equations from the theory of general relativity might enable time travel into the past. (That theory essentially discusses how large objects distort space-time, which we feel as gravity.)
So how may Einstein's theory make time travel possible? Well, a method would be to break the cosmic speed limit and go quicker than the speed of light — but that probably would not work, because an object going at that speed would have infinite mass. Another chance would be to make "wormholes" between points in space-time, although this could probably work for under tiny particles. There are even a lot of exotic prospects out there, like using black holes, large cylinders or cosmic strings to play with the fabric of space-time.
"When it comes to the past," Sutter said, "the arithmetic of general relativity will enable a number of strange situations where you'll be able to end up in your own past. but all of those scenarios end up violating other known physics, like requiring negative mass or infinitely long rotating cylinders. Why does general relativity enable past time travel, but other physics continuously jump in to spoil the fun? we honestly do not know."
But that does not mean that scientists are dropping. In 2015, Ali Övgün of eastern Mediterranean University in Cyprus said wormholes might be possible in zones with dark matter. (This could be a theoretical sort of matter that can't be seen or otherwise detected with telescopes, but does show itself in its gravitational effects on other bodies.) while his equations show wormholes may occur in these regions, Övgün same he's still checking out proof. "It is only mathematical proof," he said. "I hope someday it'll be possible to conjointly find direct experimental proof."
Even the world-renowned scientist stephen hawking was entranced by the idea of time travel before his death this year, once he mentioned in the Daily Mail how apart could make it attainable. "Around and around they'd go, experiencing just half the time of everyone distant from the black hole. The ship and its crew would be travelling through time," he wrote in 2010. However, scientist Amos Iron at the Technion-Israel Institute of Technology in haifa, Israel, said a machine circling a black hole would most likely disintegrate before moving that quickly