1. François PASSEBON & Jack WILLIS
HST 2006
present …

2. If you compress a gas in a pump, it becomes hotter,
and if you release the pressure of this gas, it cools
I pump,
therefore I am

4. An animal, or a human body, for example, emits
some infrared radiation that can be detected
by an infrared camera
Color is related to temperature

5. Dicke and Gamov, two physicists, calculated independently in 1946 and 1948, that as the Universe has cooled, we should be able to detect microwave radiation throughout the sky …
I’m Gamov
I’m Dicke

6. Long
wave-
-length
Low
temperature

7. Max Planck, another physicist,
had given the explanation of the
shape of the radiation in 1900
The colder the body,
the longer the wavelenght

8. But, in 1964, the radiation predicted by Gamov
was finally detected, with this antenna …
antenna
Penzias
Wilson
… by Penzias and Wilson, two physicists
from the Bell labs, who got the Nobel prize in 1978

9. In fact, the snow that one can see on an untuned TV
is also due in part to that radiation emitted by the
Universe as it was just 380,000 years old !
We’ve a lot of
work today !

10. Original temperature of the radiation : 3000 K
Today, it is only 3 K
The cooling says how far the light has travelled
13,7 billion years : the age of the Universe

11. In 1992, the COBE satelite (Cosmic Background explorer)
gave the first image of the radiation
COBE was launched on November 18, 1989

12. In 1992, the COBE satelite (Cosmic Background explorer)
gave the first image of the radiation
 Before correction of the Earth movement around the Sun
 Before correction of the microwave radiation emitted by our own galaxy
 The final image of the microwave Radiation

13. WMAP was launched on June 30, 2001
In 2003, the WMAP satelite gave a better resolution
of the small fluctuations of temperature
(WMAP = Wilkinson Microwave Anisotropy Probe)
WMAP was launched on June 30, 2001

14. Whereever it looked, WMAP measured the same data.
So, the big-bang must have taken place at the same time everywhere

15. But we can also observe small fluctuations of temperature, that may have lead to the formation of the galaxies

16. Small fluctuations, compared to these at the surface
of the Earth !

17. To know more about the blackbody spectrum :
Back to the begining

18. Where does the matter of the universe come from?
1 proton for every 1,000,000,000 photons
How did structures in the universe form?
Ripples + Dark Matter

19. Mass is just condensed energy
E = mc2
Mass is just condensed energy
E → m
Albert Einstein, 1905

20. Temperature: T → very large
What was the origin of this early matter (and antimatter) in the Early Universe?
Early Universe
Size: a → 0
Age: t → 0
Temperature: T → very large
T ~ 1/a, t ~ 1/T2
Energies: E ~ T

21. Every particle has an antiparticle
Based on Einstein’s Relativity + Dirac’s Quantum Theory + Feynman’s description in Quantum Field Theory
We conclude:
Every particle has an antiparticle

22. Why do we not see this in our evidence? Current evidence suggests:
Dirac predicted the existance of antimatter in 1928
He predicted antimatter would have the same mass but opposite internal properties of matter
1957: particles and antiparticles spinning in same direction behave differently
1964: CP violation shown in weak decays of K0 mesons indicating matter does not behave exactly as antimatter.
Current evidence suggests:
Because of asymmetry, almost all particles and
antiparticles were annihilated except for
a small number of particles

23. Density Budget of the Early Universe Theory of inflation, measurement
● Total Density ~ critical
Theory of inflation, measurement
of microwave background: ΩTot = ~ 1
● Baryon Density small
Big-Bang nucleosynthesis, CMB:
ΩBaryons ~ few %

24. The Density Budget of the Universe
● Total Density ~ critical
Theory of inflation, measurement of microwave background: ΩTot = ~ 1
● Baryon Density small
Big-Bang nucleosynthesis, CMB:
ΩBaryons ~ few %
● Total Matter Density much larger
Clusters of galaxies
Ωmatter ~ 25%
● Mainly cold dark matter
Enables structure formation

25. What caused the formation of the structures of the universe and what was the origin of masses and forces?
Evidence indicates that as the universe cooled after the Big Bang….
These particles began to cluster….
And in these clusters developed patterns….
Such as quarks….
And atoms

26. FORCES How do these particles stay together to form structure?
Standard Model: Gravity, Electromagnetic, Strong and Weak

27. Two Theories describe the forces: Quantum Electrodynamics and
Quantum Chromodynamics.
Quantum Electrodynamics (QED):
Electric charge Atoms Molecules
Quantum Chromodynamics (QCD):
Colour charge Baryons Nucleus

28. At current resolution we see the universe as it was ~ 380,000 years after the ‘Big Bang”
What will we see next?
Perhaps…..