Time Travel

Do you feel that if you could use time and go in future and see what stocks are high then come back and buy those, it would be sort of a life insurance. Or go back in time and watch World War II with your own bare eyes or go to other galactic dimensions like Rick and Morty?

For ages time travel has people spellbind. Even religions have examples of time travel. In Hindu mythology, the Marhabharata mentions story of King Raivata Kakudmi who travels to heaven to meet the creator Brahma and when he returns he realizes a lot of time has gone on the planet.

In Islam, Shab-e-meraj is the event that marks the night Allah took Muhammad(PBUH) on a journey from Mecca to Jerusalem and then to heaven and when he returned, the bed was still warm and chain of the door was still moving.

Einstein in 1915 published General Relativity. It contains geometric theory of gravitation and current description of gravitation in modern Physics. According to General Relativity objects in gravitational field behave similar to objects within an accelerated enclosure.

for example the observer will see the ball same way in a rocket as it does on earth provided that acceleration of rocket is equal to 9.8m/s².

Light is deflected by high and slows down in high gravitational fields then in the absence of it.

Wormholes:

They are a hypothetical warped spacetime which are permitted by Einstein's General Relativity. The wormholes work in following way.

One end of wormhole is accelerated to some significant fraction of speed of light and then brought back to point of origin. Wormholes bring with them the dangers of sudden collapse, high radiation and dangerous contact with exotic matter.

Possible Time Travel:

We can look back in past by studying rocks. Igneous rocks tell us about past volcanic episodes. Sedimentary rocks often record past depositional environment (e.g deep ocean, shallow, shelf) and most fossil from past.

To travel in future is a little difficult. Let's say a man travels at 99% the speed of light for 10 years and comes back to Earth. According to theory of General Relativity 27 years would've passed on Earth. These are the two most realistic methods for time travel.

Entropy:

One thing that ensures zero possibility of time travel in past is second law of thermodynamics, entropy. It states that "entropy of an isolated system can increase but cannot decrease. When you add sugar in a glass of water, sugar will automatically dissolve in water causing an increase in entropy but it can not seperate from water by itself. Similarly if a glass breaks it will not join itself. Universe is expanding continuously because of entropy and to travel in past you have to decrease the entropy of the whole universe to physically go in past which is impossible for humans.

"Even if it turns out time travel is impossible, it is important to understand why it is impossible" - Stephen Hawking

#wormhole #einstein #gravity #entropy #timetravel #timemachine #theoryofrelativity #generalrelativity #entropyfortimetravel