Universe

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

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

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

Long wave-length

Low temperature

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

But, in 1964, the radiation predicted by Gamov was finally detected, with this antenna … antenna

Wilson

Penzias

… by Penzias and Wilson, two physicists from the Bell labs, who got the Nobel prize in 1978

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 !

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

In 1992, the COBE satelite (Cosmic Background explorer) gave the first image of the radiation

COBE was launched on November 18, 1989

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

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

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

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

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

To know more about the blackbody spectrum :

Back to the begining

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

E = mc

2

Mass is just condensed energy Albert Einstein, 1905

E → m

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

Based on Einstein’s Relativity + Dirac’s Quantum Theory + Feynman’s description in Quantum Field Theory We conclude:

Every particle has an antiparticle

Why do we not see this in our evidence? 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

Density Budget of the Early Universe ● Total Density ~ critical Theory of inflation, measurement of microwave background: ΩTot = ~ 1

●

Baryon Density small Big-Bang nucleosynthesis, CMB: ΩBaryons ~ few %

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

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

How do these particles stay together to form structure?

FORCES Standard Model: Gravity, Electromagnetic, Strong and Weak

Two Theories describe the forces: Quantum Electrodynamics and Quantum Chromodynamics.

Quantum Electrodynamics (QED): Electric charge

Atoms

Molecules

Quantum Chromodynamics (QCD): Colour charge

Baryons

Nucleus

At current resolution we see the universe as it was ~ 380,000 years after the ‘Big Bang”

B I G What will we see next? Perhaps…..

B A N G