Published on Apr 06, 2017

The Physics of Time Travel

So I was reading Einstein’s Theory of Special Relativity some days ago. This theory says that space and time are really aspects of the same thing — space-time. Special Relativity also says that a surprising thing happens when you move through space-time, especially when your speed relative to other objects is close to the speed of light. Time goes slower for you than for the people you left behind. You won’t notice this effect until you return to those stationary people.

For example, Let’s assume you are 25 when you left earth and are travelling at about 99% of the speed of light. Now because you are travelling at about speed of light, so time is going slower for you in that spaceship. Now if you return to earth after 5 years(that’s according to your spaceship). You will see a lot of change. You will see (let’s say) 50 years have been passed. If you have children, then they are older than you. So technically, it took you only 5 years to travel 50 years. So you have become a time traveler.

So yeah, time travel is possible in the forward direction. But for that, we need spaceship which can travel at speed of light. Which is too much. And we are nowhere near this today.

But If time travel is possible in the future, why have our future generations not come and helped us to build such spaceship?

Like I said, Time travel is possible in the forward direction, not in the backward direction. According to Einstein, Time is the fourth dimension of space, which only moves forward. And we can see in our physics. We don’t take time as negative. It is only positive. It moves in only one direction. So it is impossible to go back to the past. However, Some scientists at NASA have proposed the Wormhole Theory, which allows time travel in backward direction too. By creating wormholes between two space-time points, you can travel in both directions. But wormholes are highly unstable. they would collapse very quickly and would only be suitable for very small particles. Also, scientists haven’t actually observed these wormholes yet. Also, the technology needed to create a wormhole is far beyond anything we have today.

Einstein’s Special Relativity Theory allows the possibility of time travel but I am not sure if we can achieve that, atleast for next 50 years.

Originally published on Medium By Priyansh Rastogi on April 6, 2017.

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