BIRTH OF ORDINARY MATTER (AND ANTI-MATTER)
World famous theoretical physicist and author, Lucasian Professor of Mathematics at the University of Cambridge (soon to be Emeritus).
Image source: Edelweiss II
L'expérience Edelweiss a pour but de détecter l'interaction de particules de matière noire avec des détecteurs bolométriques installés au sein du Laboratoire Souterrain de Modane (le LSM).
THE DARK MATTER PROBLEM
In addition to the unsolved question of the asymmetry of anti-matter, physicists are grappling with the problem of dark matter. The expansion of the universe is not slowing down. There seems to insufficient detectable matter in the universe to enable this. Scientists long ago postulated the existence of non-luminous "dark matter."
According to Stephen Hawking (2001: 187):
Recent study of the formation of galaxies has led cosmologists to believe that a significant fraction of the dark matter must be in a different form from ordinary matter. Perhaps it arises from the masses of very light elementary particles such as axions or neutrinos. It may even consist of more exotic species of particles such as WIMPS--"weakly interacting massive particles"--that are predicted by modern theories of elementary particles but have not been detected experimentally.
The evidence continues to accumulate, but our understanding of the largest portion of the the universe is in its infancy. Dark matter remains one of the most challenging puzzles in physics.
Hawking, Stephen (2001) The Universe in a Nutshell. Bantam Books, New York.
At 10-11 of a second electromagnetic force separated from weak force.
At this stage the universe was a soup of quarks, electrons, photons and neutrinos. After further cooling, at around 10-5 second, a crucial transition occured. Quark triplets condensed into hadrons (the familiar neutrons and protons). Together with the lighter leptons (the electrons, neutrinos and photons), they are the stuff of ordinary (or baryonic) matter...
Without the slight asymmetry between matter and antimatter in the early universe, we simply would not be here to tell the tale in the matter dominated visible part of our universe. When a particle of matter collides with its antimatter equivalent, the particles mutually annihilate creating pure energy in the form of gamma ray photons. The matter in the universe today is a tiny fraction of the particle-antiparticle pairs of the very early hot universe. According to Silk (1994: 89) “the initial asymmetry was only about one part in a billion.” After the annihilation of about 99.99999995% of the particle pairs, “the tiny excess of matter over anti-matter that survives… accounts for our existence.”
Silk, Joseph. (1994) A Short History of the Universe. Scientific American Library, New York.