By Michael Bryant
And Laine Tennyson
May 12, 2008
Modern Physics
SRJC
State of technology for
traveling near/faster than
light
Background credit: http://www.rpi.edu/dept/phys/ScIT/InformationTransfer/reflrefr/rr_content/refraction_20.html
Fastest space craft humans have
ever launched (New Horizons) would
take 47000 years to reach Proxima
Centauri (at 25000 m/s or .00833% c)
We need to go much
much faster
unfortunately that’s no picnic

Relativistic effects make near light travel with
conventional chemical rockets infeasible


1

KE  mo c 2 

1
 1  v22

c


Using the above equation to graph the
energy required vs. velocity to accelerate
an object of the mass of the typical
shuttle payload (~86000 kg) effectively
illustrates this point
Background credit:http://www.scifair.org/images/ParticleTracks.jpg
PUSH
ME!
•Nuclear Propulsion
-Project Orion (1960’s, fission)
-NERVA (Nuclear Engine for Rocket Vehicle
Application) (1963-1973, fission)
-Project Daedalus (1973-1978, by the Brit’s, fusion)
-Project Prometheus (2003-present)
•Electric Propulsion
-Ion/Plasma Propulsion
-Hall Thruster
-Magnetoplasmadynamic (MPD) thruster
-VASIMER (existing technology, planned
application in 2010)
•Nuclear-electric Propulsion
“Orion Style” Nuclear Spacecraft
images credit: http://www.daviddarling.info/encyclopedia/A/advanced_propulsion_concepts.html
MPD Thruster
E  mc 2
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When matter hits antimatter the
result is a huge amount of energy,
 Only would need 10g to reach
mars in 1 month
Unfortunately right now mass of
antimatter is measured in atoms, not
kg
Assuming industrial processes could
be established to manufacture
antimatter, significant technical
challenges remain
 Need to separate antimatter fuel
from regular matter of the ship
using magnetic storage rings.
 Feed system needs to be separated
magnetically as well
 Magnetic nozzle is needed to
direct energy away from ship in a
controlled manner
Credit: http://lpmpjogja.diknas.go.id/kc/a/animal/antimatter.htm
credit: http://www.nasa.gov/centers/glenn/research/warp/scales_prt.htm

Solar Sails

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Light has momentum, p=hƒ, solar sails take
advantage of this fact.
Differential Sail

Similar to solar sail, however this uses a
theoretical coating on one side that absorbs
energy more than the other side, assumes there
exists in space a constant background radiation
that is constantly impinging on all sides of the sail.
Solar Sail
Differential sail
Diode Sail
images credit: http://www.daviddarling.info/encyclopedia/A/advanced_propulsion_concepts.html
•Magnetic Sails
Magnetic Sail
credit: http://www.daviddarling.info/encyclopedia/A/advanced_propulsion_concepts.html
-M2P2 (Mini-Magnetospheric Plasma
Propulsion, under study at University of
Washington, Seattle, with NASA funding)
•Beamed energy
-Like a solar sail but asymmetric radiation
pressure is achieved by shining high
powered laser light on the sail from earth
•Interstellar ramjet
-Bussard Ramjet ( version of fusion rocket
but gets reaction mass from interstellar
medium)
credit: http://amygdalagf.blogspot.com/2005_08_21_archive.html
Bussard Ramjet
Lets first define what is meant by FTL
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
Misnomers
 A shadow on a distant wall may move at faster than the speed
of light.
 Phase velocity of the interference of waves can move faster than
c.
 A laser on a distant object can go faster than light.
We will define FTL as sending information superluminally.
http://www.wallpaperbase.com/movie-startrek.shtml
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V=H*d Where H is Hubble's constant, and d is
the distance between two objects
If you were if d>c/H then you would be
moving superluminally away from the other
object
Space time expands between all objects
http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/FTL.html

Einstein, Podolsky, and Rosen thought experiment
 Two particles (A and B) interact and spin, before moving apart in
opposite directions
 After a time, the z spin of particle A is measured and the x spin of
particle B is measured so both spins on both particles are known
exactly.
 This violates Heisenberg's Uncertainty Principle, or the particles were
able to communicate faster than light
 There are explanations, and reasons why this is not FTL travel
http://roxanne.roxanne.org/epr/einstein1.html
http://en.wikipedia.org/wiki/EPR_paradox
Commonly known as worm holes.
Bend space time
 One theory says that negative energy would be needed to keep the
worm hole open.

With sufficient bending any point in the universe could be right next to you
 Einstein came up with the idea while trying to explain fundamental particles
like electrons as space-tunnels threaded by electric lines of force.
 A prediction of his findings was black holes.

http://www.krioma.net/articles/Bridge%20Theory/Einstein%20Rosen%20Bridge.htm
www.phys.univ-tours.fr/~piotr/
www.zamandayolculuk.com/cetinbal/blackholesth.htm
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Space stretches behind you and contracts in front of you, so you are
constantly riding on a “downhill” slope.
How? In order to stretch space time like this you would need to be
covered in a shell of negative energy.
Even if we could stretch space time like this it is still unknown whether or
not you could surpass the speed of light
http://en.wikipedia.org/wiki/Alcubierre_drive


Negative mass could make Faster than light travel easy
 The equivalence principle states that every object must also have a
negative, therefore inertial mass and gravitational mass must also
have a negative
Tachyons
 Relativity states that no positive mass can be accelerated to the
speed of light, but what about a particle of negative mass? The less
energy it had the faster it would travel. These particles are called
Tachyons.
 Issues: Even if you could control a tachyon you might find it
impossible to remove energy from it.
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The Casmir affect:
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All fields even vacuum fields have
fluctuations.
If you create a cavity (two metal plates
very close together) in the vacuum then
the vacuum fluctuations can resonate in
between the plates, causing the plates to
repel, or the can be out of resonance
(negative energy density) causing the
plates to attract.
The plates attract.
Duality:

The principle of duality predicts that if
there is energy, there must also be
negative energy
http://physicsworld.com/cws/article/print/9747
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Many ideas about space travel make it
plausible to travel quickly and efficiently in
space.
Propelling yourself to the speed of light
remains impossible.
Some ideas of how to “cheat” the speed of light
exist, but none of them are testable or
achievable in the near future
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http://www.nasa.gov/centers/glenn/research/warp/scales.html
http://www.quotationspage.com/quote/33085.html
http://en.wikipedia.org/wiki/New_Horizons
http://www.nasa.gov/centers/glenn/research/warp/ideachev.html
http://www.daviddarling.info/encyclopedia/A/advanced_propulsion_concepts.html