1 Martin L. Perl SLAC National Accelerator Laboratory and Kavli Institute for Particle Astrophysics and Cosmology at Stanford University Talk presented at University of Belgrade, April 2009 Matter, Energy, and the Universe

2 ORDINARY MATTER electrons atoms molecules people stars DARK MATTER ? DARK ENERGY ? ORDINARY ENERGY chemical electrical nuclear gravitational

3 ORDINARY MATTER electrons atoms molecules people stars

4

5 All ordinary matter made up of Elementary Particles

6 The Electron is an elementary particle We cannot break it up into smaller parts

7 The Electron is an elementary particle Mass = grams = 1 gram / … Size less than centimeters May have no size Smallest electric charge known

8 The Electron is an elementary particle electric field perhaps no center

9

10

11 ORDINARY ENERGY chemical electrical nuclear gravitational

12 Chemical Energy

13 Electrical Energy

14 Nuclear Energy

15 Gravitational Energy in the Universe

16 Gravitational energy is more important than all other ordinary energies in the behavior of the universe.

17 Gravitational Energy on Earth

18 Gravitational Energy in the Heavens Sun OUR GALAXY

DARK MATTER ?

20 Dark Matter In the 1930’3 Zwicky showed that the velocity of galaxies would cause a cluster to fall apart unless the galaxies has hidden mass called Dark Matter

21 Assumed distribution of dark matter in Solar System Dark Matter

22 Dark Matter

23 Dark Matter

24 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.

Dark Matter First Method: Assume the earth is passing through Dark Matter particles and look for collisions with ordinary matter. No confirmed evidence

Dark Matter When Large Hadron Collider in Geneva starts, look for Dark Matter particles

Dark Matter Warning: Some astronomers don’t believe in the existence of Dark Matter. Instead they change the equations describing the behavior of gravity.

DARK ENERGY ?

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

Dark Energy Present model, not proven Visible universe

Dark Energy Present model, not proven 4 % ordinary matter + ordinary energy 26 % Dark Matter + ordinary energy 70 % Dark Energy

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.

There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy. Shakespeare