How time travel theoretically works in less than 1000 words

Science fiction writers and readers have dreamed of time travel for hundreds of years, and while it’s not possible to go through a wormhole into the future or step into a time machine, some researchers believe that there are legitimate ways to travel through time. . . They just aren’t easy, safe, or even slightly practical.

two black holes

Traveling to the future is relatively easy – just wait. Going back in time even a few seconds, however, might require a terrifying sequence of events, like two black holes colliding. In the vicinity of a black hole, space and time are so distorted that if two of them give high five, a path could be traced around the two space anomalies that would take a traveler back… to the beginning of their journey. According to astrophysicist Neil deGrasse Tyson, “it would be quite a journey for any material swirling in its vicinity”, so it’s probably not worth going back to where you started unless you have a death wish or some sort of fetish. of  Groundhog Day  .  _ 


The idea of ​​wormholes appears repeatedly in science fiction. Theoretically, if you go into a wormhole, you’ll come out at a different point in time and space, but that’s easier said than done. The problem isn’t finding one: scientists believe that space is absolutely terrible at things. It’s just that they are a billion billion times smaller than an electron. Something that small is impossible to study, so while some researchers believe it might be possible to enlarge these tiny wormholes to a size that someone could traverse, it’s unclear how far one could travel or whether anyone would survive the trip.

Speed ​​of light

The best way to travel to the future is the speed of light. Thanks to the weirdness of physics, the faster you travel through space, the slower you travel through time. We’re not talking about a run around the block – if you really want to make this kind of time travel work, you’re going to have to plan for a long trip while moving at the speed of light, which is incredibly difficult to do. Even astronauts orbiting Earth approach only one-tenth the speed of light. If you could build a craft that could handle it, however, you could theoretically land thousands of years into the future, after working in space at the speed of light for just a few years.

The Time Donut

Sci-fi is full of time machines, from the hottest cars to the biggest phone booths inside, but while you can’t just jam a flux capacitor into any old malfunctioning automobile, you  can . build a time machine that works as long as you have a big enough donut. Scientists hypothesize that a donut-shaped hole inside a sphere of normal matter can bend time. Using a forced gravitational field to create a time-like curve inside the sphere, whatever that means, the time traveler only needs to run around the donut track inside the “machine”. With each turn, they will go back to the past. The downside is that to build a time machine of this magnitude, you would need a lot of money and a whole team of scientists, so start writing those funding proposals now.