The Planck satellite probes the beginning of the universe

During the first very hot phases of the universe, there were protons, neutrons, electrons and photons. Because of the universe expansion and the cooling it produced, most particles lost a large part of their energies and after a few seconds photons were no longer able to break proton-neutron combinations. Deuterium nuclei began to appear and they began to attract one neutron and one proton, it was the birth of helium nucleus. The same process repeated to form all the nuclei that are present today. This was the state of knowledge deduced from the very new theory: the big-bang theory in the beginning of the fifties. In fact this process was valid only for light nuclei because a few minutes after the big-bang the cosmos was so diluted that large distances between nuclei prevent them from colliding with one another and then to form heavier nuclei. Heavier nuclei began to appear millions years later in stars and even heavier ones in star explosions. In 1965 the cosmic background radiation was discovered which was a proof of the big-bang theory. The results of the Planck satellite published in december 2014 confirmed that the geometry of the observable universe is euclidean which means flat and that today's universe is composed of 68.6% of dark energy, 26.6% of dark matter and 4.9% of ordinary matter. Dark energy and dark matter components have been so far never detected, it might be the hint that gravitation laws have a flaw. (A.C.)