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Martin L. Perl ([email protected])
SLAC National Accelerator Laboratoryand
Kavli Institute for Particle Astrophysics and Cosmology at
Stanford University
Talk presented at University of Belgrade, April 2009
Matter, Energy,and the
Universe
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ORDINARY MATTERelectrons
atomsmolecules
peoplestars
DARK MATTER
?
DARK ENERGY
? ?ORDINARY ENERGY
chemicalelectricalnuclear
gravitational
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ORDINARY MATTERelectrons
atomsmolecules
peoplestars
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All ordinary matter made
up of Elementary Particles
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The Electron is anelementary particle
We cannot breakit up into smaller
parts
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The Electron is anelementary particle
Mass =10-27 grams =1 gram /1000000….00000
Size less than 10-16 centimeters
May have no size
Smallest electric chargeknown
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The Electron is anelementary particle
electric field
perhaps no center
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ORDINARY ENERGYchemicalelectricalnuclear
gravitational
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ChemicalEnergy
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ElectricalEnergy
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NuclearEnergy
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GravitationalEnergy in theUniverse
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Gravitationalenergy is more important thanall other ordinaryenergies in thebehavior of theuniverse.
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GravitationalEnergy onEarth
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GravitationalEnergy in theHeavens
Sun
OUR GALAXY
DARK MATTER
?
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Dark Matter
In the 1930’3 Zwickyshowed that the velocityof galaxies would cause acluster to fall apart unlessthe galaxies has hiddenmass called Dark Matter
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Assumed distribution of dark matterin Solar System
Dark Matter
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Dark Matter
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Dark Matter
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Dark MatterWe hypothesize that Dark Matterconsists on a new type of electrically neutral, elementaryparticle; but there is no proof.
Therefore on earth there are twokinds of searches for the DarkMatter particle.
Dark MatterFirst Method:Assume the earth is passingthrough Dark Matter particles andlook for collisions with ordinarymatter.
No confirmed evidence
Dark MatterWhen Large Hadron Colliderin Geneva starts, look forDark Matter particles
Dark Matter
Warning: Some astronomersdon’t believe in the existenceof Dark Matter. Instead theychange the equations describing the behavior of gravity.
DARK ENERGY
? ?
Dark Energy
•First evidence, 10 years old,that we do not understand therate of expansion of the universe.
•A great surprise.
•A great mystery
Dark EnergyPresent model, not proven
Visible universe
Dark EnergyPresent model, not proven
• 4 % ordinary matter + ordinary energy• 26 % Dark Matter + ordinary energy•70 % Dark Energy
Dark Energy
Dark Energy is a new kind ofenergy hypothesized to fill allof space.
Therefore should be on earthalso. Most physicists believeits effects on earth are too small to be detected.
I disagree and am looking for an experimental method todirectly detect Dark Energy.
There are more thingsin heaven and earth,Horatio, than aredreamt of in yourphilosophy.
Shakespeare
