Histoires de l'Univers et du Big bang

Stories of the Universe and the Big Bang

Françoise COMBES, astrophysicist at OBSPM
Ever since Einstein's work on general relativity at the beginning of the 20th century, we have known that the Universe cannot be static. Space expands and contracts.
Observation shows that galaxies are all moving away from each other with a speed that is proportional to their distance - Hubble-Lemaitre's law. Numerous observations have confirmed the "Big Bang" theory, in which the Universe began in an extremely hot and concentrated state: the primordial nucleosynthesis of light elements such as helium and deuterium, the detection of the cosmic microwave background, a black body at 3°Kelvin, and the discovery of minute fluctuations in density in this microwave background, 400,000 years after the Big Bang, which gave rise to the galaxies. Since 1998, we have known that the expansion of the Universe is accelerating, due to mysterious dark energy.
Do the great structures of the Universe come from quantum fluctuations in the vacuum, made macroscopic by the original inflation?