Time Travel

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Time Travel

• Can we travel through time and through space?

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Examples of time shaving

• When people travel in space they often return
  aged less than people on earth.
• A plane which flies around the entire world with
  an atomic clock is a fraction of a second behind
  a clock stationed on earth.
• What can we figure from this?

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Time Travel is Possible

• We know that objects traveling at high speeds
  age more slowly than a stationary object. This
  means that if you were to travel into outer space
  and return, moving close to light speed, you
  could travel thousands of years into the Earth's
  future.

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Newtons theories of time

• Newton's came up with a mathematical definition
  of how motion changes with time. He showed that
  the force causing apples to fall is the same
  force that drives planetary motions and produces
  tides. However, Newton was puzzled by the fact
  that gravity seemed to operate instantaneously at
  a distance.

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Einsteins Theories on Time

• Einstein's general theory of relativity changed
  gravity from a "force" to the movement of matter
  along the shortest space in a curved spacetime.
  The Sun bends spacetime, and spacetime tells
  planets how to move.
• Newton believed that the universe was run by a
  single absolute time that could be symbolized by
  an imaginary clock off somewhere in space.
  Einstein changed all this with his relativity
  theories .

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The Relativity of Time

• Einstein's revolutionized physics with his
  "special theory of relativity" by showing how
  time changes with motion.
• Time is relative to the speed at which one is
  traveling, so there is no one watch that everyone
  can follow.
• If an alien was traveling at the speed of light,
  he would see your entire life in the blink of an
  eye.

7
Time Issues

• We are a just a moment in astronomic time.
• We cant comprehend the many mysteries of time
  and space.
• However we have come very far by questioning the
  universe we live in. Yet many key questions we
  have are left unanswered.
• Questions such as is time a real thing? Does it
  only go in one direction? Does it have a
  beginning or an end? What is eternity? We dont
  have any answers that provide full satisfaction.

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Applications of Timespace

• The issue of timespace encompass time travel,
  higher dimensions, quantum superspace, and
  parallel universes.
• Stephen Hawking has proposed using wormholes to
  connect our universe with an infinite number of
  parallel universes.
• Edward Witten is working on string theory, which
  can explain the nature of both matter and
  spacetime in one encompassing theory.

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The Grandmother Paradox

• Paradox Suppose someone travels back in time and
  kill his grandmother. This means that the time
  traveler would have never been born in the first
  place.
• Either the past is totally defined and the person
  will not succeed in killing his grandmother or
• When the time traveler kills the grandmother he
  immediately creates a new quantum universe, in
  essence a parallel universe where the young
  grandmother never existed and where our time
  traveler is never born. The original universe
  still remains. This is Stephen Hawkings theory.

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Multiple Dimensions?

• Time can simply be looked at as another very
  large dimensions. To avoid the obvious paradoxes
  involved in travel in the fourth dimension we
  require the existence of a fifth dimension.
• If super string theory represents a deeper
  understanding of reality, then perhaps there are
  actually ten dimensions. Five, ten or more, the
  Universe is even bigger than we imagined.
•  

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Final Thoughts

• Very complicated equations show us that we can
  travel anywhere in the Universe in under two
  years if we travel just below the speed of light.
  On our return, however, we would find that a
  tremendous time has passed for those left behind.
  
• If we ever can travel faster than the speed of
  light, and come back, is it possible that we will
  emerge in another Universe? Yes, but this may
  present no problem. For if it is similar to our
  own, in that up to the point of departure we have
  common history, then neither we, nor the
  inhabitants of this new Universe, will ever know
  the difference.

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THE END
ANY QUESTIONS?