Like every single nerd who has read comics and watched sci-fi shows, and even written a few fictional stories on the topic, I really like the idea of time travel. Most scientists do too, and there’s an ongoing debate about whether time travel is possible.
If it is, and humans get the chance to travel back in time, can we alter the past? Only view it? Will a single small action cause a massive ripple effect that eventually leads to an apocalyptic or dystopian future?
The properties of time
Thanks to Albert Einstein, we know that time is relative and based on speed. Depending on your speed, time moves differently. A popular example is having two twins who were born at the same moment, and have one stay on Earth and the other go into space and circle the globe at the speed of light.
Then the twin in the spaceship would be younger by a certain time span despite the same amount of time passing both on Earth and in space. This works for astronauts too, making them slightly younger (often by microseconds) from their twins on Earth. So astronauts not only get to go into space, but they are the world’s first-time travelers. Man, they have all the fun!
Time is also considered an illusion, and not constant for everyone, it’s only the way we perceive it that makes it real to us.
Time travel theories
Some theories of time travel include being able to move an object in a vacuum at the speed of light which some scientists say is possible. Others include using wormholes, which are technologically out of reach as of now, and going through them.
And there is the ever-popular time machine, which has been popularized by science fiction. However, time machines need a component of matter called “negative energy density” which is either theorized to be very rare or existing in only small qualities that probably wouldn’t power a time machine.
Some scientists also believe that having a loop of normal matter, almost like a racetrack, would allow a fast moving person or object to race back in time. Still, it would have to be extremely precise, and the gravitational forces could be lethal.
What I believe
I personally would like to see time travel exist, but if speed is the key then normal humans probably couldn’t access it, there’s a reason why only speedsters can travel through time in comics and movies and it’s because they cannot only move fast enough but also withstand the pressure of time travel that would be lethal to someone else.
So we’d need meta-humans or powered people first, in which case I’d probably volunteer!
In all seriousness, the physics world is constantly changing, and things that seem impossible today are often made possible once scientists discover these small changes. So maybe there will be a way to travel through time some day in the future, and until then I’ll stick with my comics.