Time Travel

Introduction Time travel is the concept of moving between different points  in time.  Time  travel  could  involve  moving backward in time to a moment earlier than the starting point, or forward to the future of that point without the need  for  the  traveller  to  experience  the  intervening period (at least not at the normal rate). Time  travel  has  been  a  common plot  in science fiction. The  theories  of special and general  relativity allow methods  for  forms  of  one-way  travel  into  the  future via time  dilation,  it  is  currently  unknown  whether the laws of physics would allow time travel into the past. 

Einstein’s Great Idea•Einstein proposed the theory of SPECIAL RELATIVITY and GENERAL RELATIVITY

• It states that space and time are really aspects of same thing :SPACE-TIME

•According to this time moves differently to different people corresponding to there relative speed

Forwards/Backwards Time Travel•Going forward in time is (relatively) easy•Going back is much harder•But Einstein’s theory of general relativity seems to allow it

•Forward time travel: my time goes slower than yours (like aging slower than everyone else)

•Backward time travel: my time goes faster than yours (like aging faster than everyone else). 

• If you don’t want to become young or old, you can use the Time Tunnel method which will come in later slides.

Wormholes

•A wormhole is a theoretical passage through space-time that could create shortcuts for long journeys across the universe.

•Wormholes are predicted by the theory of general relativity. But be wary: wormholes bring with them the dangers of sudden collapse, high radiation and dangerous contact with exotic matter.

•Einstein's theory of general relativity mathematically predicts the existence of wormholes, but none have been discovered to date.

•Entering  a wormhole  is  50  to 60 times more dangerous than a black hole. 

What Happens in a Wormhole• In a wormhole, you will be teleported through the 

‘Time Tunnel’ when your craft goes in it will exit the Tunnel and comes out from the wormhole at very distant place or another universe(if exists)whithin a short span of time. 

•There are some scientists who say that"A wormhole is not really a means of going back in time, it's a short cut, so that something that was far away is much closer,"

  

The Paradox of Changing the Past

•Time travel is possible, but it does not and cannot change the past

•The idea of travellig to the violates the basic theory of universe “CAUSE AND EFFECT” 

•Cause and effect theory states that effect cant happen before the cause happens

The Grandfather Paradox

• If you could go back in time, you could kill your grandparents before your dad was born then there would have been no you to make a time machine and go and kill him! Which means that you can’t have killed him. 

•This is the most famous paradox of time travel.

Multiverse Theory•  Parallel universes can exist individually, or grouped together as the “multiverse,” and offer the possibility of a totally different reality in which someone, or something, can exist, or hop back and forth between.

• The laws of nature may be different in one parallel universe as they are in another, and in respect to time travel, would provide multiple versions of the future in which someone could exist, or not exist at all.

• Light speed limitations may not exist in a parallel universe, and the paradoxes that keep us from traveling back in time would be null and void if we could jump into a different historical timeline.

Many World Interpretation • It states that each time a different choice is made at the quantum scale, a universe arises to accommodate that choice, thus creating infinite new worlds popping up all the time.

•Alternate timelines, each with their own forward arrow of time and their own history, may exist then, allowing time travelers to jump into another version of history and override those pesky paradoxes.

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