Martin L. Perl ([e-mail])

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Matter, Energy, and the Universe
Martin L. Perl (martin_at_slac.stanford.edu) SLAC
National Accelerator Laboratory and Kavli
Institute for Particle Astrophysics and Cosmology
at Stanford University Talk presented at
University of Belgrade, April 2009
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ORDINARY MATTER electrons atoms molecules people s
tars
ORDINARY ENERGY chemical electrical nuclear gravit
ational
DARK ENERGY ? ?
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ORDINARY MATTER electrons atoms molecules people s
tars
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All ordinary matter made up of Elementary
Particles
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The Electron is an elementary particle
We cannot break it up into smaller parts
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The Electron is an elementary particle Mass
10-27 grams 1 gram /1000000.00000 Size less
than 10-16 centimeters May have no
size Smallest electric charge known
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The Electron is an elementary particle
electric field
perhaps no center
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ORDINARY ENERGY chemical electrical nuclear gravit
ational
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Chemical Energy
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Electrical Energy
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Nuclear Energy
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Gravitational Energy in the Universe
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Gravitational energy is more important than all
other ordinary energies in the behavior of
the universe.
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Gravitational Energy on Earth
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Gravitational Energy in the Heavens
Sun
OUR GALAXY
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DARK MATTER ?
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Dark Matter
In the 19303 Zwicky showed that the velocity of
galaxies would cause a cluster to fall apart
unless the galaxies has hidden mass called Dark
Matter
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Dark Matter
Assumed distribution of dark matter in Solar
System
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Dark Matter
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Dark Matter
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Dark Matter
We hypothesize that Dark Matter consists on a new
type of electrically neutral, elementary particle
but there is no proof. Therefore on earth
there are two kinds of searches for the
Dark Matter particle.
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Dark Matter
First Method Assume the earth is passing through
Dark Matter particles and look for collisions
with ordinary matter.
No confirmed evidence
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Dark Matter
When Large Hadron Collider in Geneva starts, look
for Dark Matter particles
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Dark Matter
Warning Some astronomers dont believe in the
existence of Dark Matter. Instead they change the
equations describing the behavior of gravity.
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DARK ENERGY ? ?
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Dark Energy

• First evidence, 10 years old,
• that we do not understand the
• rate of expansion of the universe.
• A great surprise.
• A great mystery

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Dark Energy
Present model, not proven
Visible universe
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Dark Energy
Present model, not proven

• 4 ordinary matter ordinary
• energy
• 26 Dark Matter ordinary
• energy
• 70 Dark Energy

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Dark Energy
Dark Energy is a new kind of energy hypothesized
to fill all of space. Therefore should be on
earth also. Most physicists believe its effects
on earth are too small to be detected. I
disagree and am looking for an experimental
method to directly detect Dark Energy.
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There are more things in heaven and
earth, Horatio, than are dreamt of in
your philosophy.
Shakespeare