Pauline Gagnon Physicist and communicator at CERN The dark side of the Universe.
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Transcript of Pauline Gagnon Physicist and communicator at CERN The dark side of the Universe.
Pauline GagnonPhysicist and communicator at CERN
The dark side of the Universe
Shrimp Nebula© VLT, European Space Observatory
• Convince you all of the existence of dark matter
• Review how one can catch dark matter
Plan
fi
©2000, 2001 B Katzung, Andromeda galaxy
4
dark matter 27%
dark energy 68%
visible matter 5%
Universe content
© NASA, Orion nebula
Dark energy:
Discovered in 1998 while studying the relative speeds of galaxies
The Universe expansion is accelerating
A completely unknown type of energy must be causing this expansion
Physics Nobel Prize in 2011 went to Saul Perlmutter, Brian Schmidt and Adam Riess
8
dark matter 27%
dark energy 68%
visible matter 5%
✓
Universe content
What is generating the gravitational pull needed to maintain these
galaxies together?
12
Dark matter provides the gravitational force needed to maintain these galaxies together
Mais comment mesure-t-on la composition de l’Univers?
1 second
Protons and neutrons form
380 000 years
Atoms form
1 billion years
Stars and galaxies form
13.7 billion years
2.7 degrees
1032 degrees
The Big Bang
Stars and Dust Across Corona Australis © Ignacio Diaz Bobillo
Rayonnement fossile
The Universe became transparent 380 000 years after the Big Bang
The photons present then are still moving around freely
But the Universe expanded and they cooled down
We still observe them today in the form of microwave background at 2.725 degrees Kelvin
Cosmological microwave background
Width and temperature of each lump(or angular spectrum measured by Planck)
Angular width of all structures observed in the Universe
Tem
para
ture
fluc
tuati
ons
in (μ
•K)
Big Bang Standard Model
Λ-CDM model: a model with 6 free parameters including
Ωd : dark matter densityΩΛ : dark energy density
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Dark energy68%
Dark matter27%
Matter5%
Ωd
Ωd
ΩΛ
How did the Universe evolve
from an immense fog of free particles…
…to an Universe filled with stars and galaxies?