Space-time

Present:
Warp Cores and Wormholes!
Faster than Light travel in SciFi and reality…
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Why can’t we travel faster than Light?
The science arena: general relativity
Warp speed and wormholes: what are
they?
Wat does science have to say about them?
– Alcubierre’s ‘warp drive’
– Thorne-Morris wormholes
– Problems and challenges
Discussion: FTL travel: Fact or Fiction?
Why can’t we travel faster than Light?
Albert Einstein (1879-1955)
Special Theory of Relativity
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“Special” because it deals with the special case of constant
motion
“Laws of nature are the same for systems at rest or systems
moving with a constant velocity”
– Do you feel different in an airplane flying at constant speed?
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The speed of light is always constant (ca 300.000 km/sec)
Special Theory of Relativity
• Consequences
Time dilation
Twin paradox
Lorentz contraction
What happens near the speed of
light?
Time comes to a standstill!
Mass becomes infinite!
So what would happen if
we go faster than light?
Time, mass, length become imaginary!
And that is really asking for trouble
The light speed is the highest speed we will
possibly reach!
And even that only in approximation!
Thanks for Nothing Albert E.!
Well, then we will settle for
something slower..
• Problem: The Universe is far too big
– To Alpha Centauri: 4 years
– To Delta Quadrant: 70.000 years
– To Pegasus Galaxy: 3.000.000 years
We will somehow have
to travel faster than
this in order to get
somewhere
Star Trek’s Solution:
Warp Drive!
Stargate’s Solution
Wormholes!
Some other ideas
Star Wars hyperspace
BSG jump drive
Andromeda slipstream drive
Infinite improbability drive
Babylon 5 jumpgate
Babylon 5 hyperspace
Farscape Starburst
Warp Drive according to the books
• Warp drive works by distorting the fabric of
space.
• Space-time is contracted in front of the ship and
expanded behind it.
• The starship itself rests between the two spacetime
distortions.
• This warped space, together with the region inside it,
accelerates off at 'warp speed' and the vessel then
'surfs' the wave in spacetime created by this
distortion.
• Memory-Alpha.org
Spacetime??
• Three numbers are necessary to describe a
place
– Latitude, Longitude, Altitude
• Four numbers are necessary to describe an
event
– Latitude, Longitude, Altitude, time
• Time may be seen as a fourth dimension
• Spacetime = Space + Time as a whole
Space time can be shaped?
• Think about the earth’s surface
• Two-dimensional spherical surface
• Space time shapes are four-dimensional
The cause: Gravity!
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Rµν− gµνR=8π GTµν
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Gravity shapes spacetime
Spacetime can expand and shrink?
Big Bang
Blowing up a balloon
So how does a warp drive work?
• “Alcubierre-metrics”
Expansion
“warp bubble”
Shrink
“warp bubble”
Expansion
Shrinking
• The spaceship itself is located in a flat
region of space and moves relative to that
at sub-lightspeed
• Einstein should be satisfied
So we can start building?
• There are some serious problems
– Gigantic energy requirements
– In order set up a warp conduit one has to
travel the first time the old fashioned way
– Stabilizing requires “exotic” matter (and we
don’t know if that exists: superstring theory
allows for it (at least one version does!)
• Bajoran Wormhole: stabilized by verterons
– Quantum mechanical problems (causality)
OK, what about wormholes?
What is a wormhole?
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“Shortcut through space”
Special type of distortion
Wormhole terms
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Inter-universe – between two universes
Intra-universe – within the same universe
Lorentzian – large wormhole
Euclidean – Microscopic wormhole
Traversable wormhole – allows (human)
travel
First solution: The Schwarzschild
wormhole
Black Hole
Impossible:
Violates laws
of Nature
“White” Hole
Also: Unstable
and nontransversable
Better: The Morris-Thorne (MT)
wormhole
Exotic matter
M.S. Morris, K.S. Thorne, U. Yurtsever,
Wormholes, Time Machines and the Weak Energy
Condition,
Phys. Rev. Letters 61, 1446 (1988)
Transversable!
Requires Exotic Matter
Peeping though a MT wormhole
Distortion of vision
Thomas Muller, Am. J. Phys., Vol. 72, No. 8, August 2004
Summarizing
• Light Speed is too slow to allow effective
interstellar travel
• Einstein does not allow us to go any faster
• Reshaping space would allow us to go
faster (at least in theory)
• But there are still many serious difficulties
to solve..
So : Warp Speed and Wormholes
will be Fact or Remain Fiction?
Wat do you think…???