Time travel has been of interest to people for centuries, and serious scientists decided to test how it is possible
There are many hypotheses about how time travel is possible, thanks to wormholes, Tipler cylinders, and other Einstein-inspired theories.
Many scientists take this issue very seriously, including Stephen Hawking. The famous physicist believes in the scientific possibility of time travel and even says that he knows how to build a time machine. He also wondered, "If time travel is possible, where are the tourists from the future?" This is a good question and we will try to answer it.
1. Why We Think Time Travel Is Possible
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In the last century, scientists have proposed several theories to leap into the future. Unfortunately, going back to the past is much more difficult.
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According to Einstein's theory of general relativity, a wormhole can serve as a bridge, the shortest path connecting two points in spacetime. But there is one catch: when a way is found to create a wormhole, it will allow you to make a leap into the future, but it will allow you to return to the past no further than before the moment it was created.
Another option is to use the so-called time dilation: for a moving clock, time flows more slowly than for a stationary one. The clock on the International Space Station runs slower than on Earth. And if you go on a trip in a spaceship at super-high speed, time will pass faster for people on Earth. You can make a circle around the galaxy and return to Earth in the future. The question is, how far can we go and can we go back?
We don't really know that. And we won't know until we try, but at the moment we don't have the means to do it. However, there is an easy way to find out if time travel is possible in principle - to find time travelers among us. You don't even need any laboratories for this! And that is what some scientists have tried to do.
2. Party approach
Stephen Hawking
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In 2009, Stephen Hawking hosted a Time Traveler Party in Cambridge, England. He always assumed that tourists from the future could be proof of the possibility of time travel, so he only invited them, but no one came.
The idea is probably not that ridiculous. Perhaps Hawking really expected someone to come. The sly scientist didn't tell anyone about the party before it was over. However, someone in the future had to find out about this event after the fact and jump into a time machine to come to a party with a famous physicist.
Kip Thorne
puhy.com
However, there is a good chance that this was just proof of Hawking's point of view. As Kip Thorne writes in his book "Black Holes and Time Folds", the main option for time travel is wormholes, which, as mentioned above, will not lead you to an event that happened before the discovery of a way to create them. So if people from the future built a time machine that we don't have at the moment, they still wouldn't be able to get to Hawking's party.
3. Conventional approach
Amal Doray
flickr.com
A few years before Hawking's party, an ambitious MIT graduate student tried a similar but even stranger approach. Instead of hiding the event, Amal Doray convened an entire convention on time travel and urged everyone to spread the word about it:
“We need volunteers to publish the details of the convention so travelers in future millennia can learn about it. This convention must not be forgotten! We need publications in such giants as the New York Times, the Washington Post, books, and so on. If you have any strings, pull on them."
Dreams Come True: The New York Times published a report, wrote an article in Wired, even Tina Fey made fun of the convention on Saturday Night Live.
However, the PR didn't work. “The convention was a mixed bag,” says Doray. "Unfortunately, we have no confirmation that we were visited by time travelers, but at the same time, many of them may have arrived incognito to avoid endless questions about the future."
4. Academic approach
Robert Nemiroff and Teresa Willson
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Earlier this year, a couple of physicists published a study report "Finding Traces of Time Travelers on the Internet." Instead of organizing events and advertising them to attract people from the future, these scientists began to hunt for evidence of their Internet connection.
Robert Nemiroff and Theresa Willson of Michigan Technological University searched Twitter, Facebook, Google, Google+, and even Bing, but between 2006 and 2013, they found no mention of two events from the future that haven't happened yet.
It was a good try. However, given the limitations of the experiment, they were looking for a very specific time traveler. Why would it have occurred to him to put words from the future on the Internet? “The time traveler may have tried to collect historical information that did not survive in the future, or was looking for some future event, because he believed that it had already happened or is still happening in our time,” the article explains.
This is probably a little silly. But it's no more foolish than throwing a party and not inviting anyone or hosting a convention on technology that hasn't even been invented yet. Unsurprisingly, these events became the occasion for comedy shows.
5. What's the matter
© universetoday.com
The whole point is that all these events were the result of the spread of some ideas of theoretical physics. The time machine has not yet been invented. If that ever happens, a new era of time travel will begin. However, we will not be able to travel to a point in time before it was invented.
However, time travel is possible. In fact, astronauts aboard the International Space Station travel in time every day, albeit for only a few microseconds. The principles of relativity and the very nature of spacetime make this possible. So if you want to see the time traveler, you just need to settle down next to the astronaut.