ABSTRACT
The Belgian astronomer Georges Edward Lemaitre suggested in 1927 that in the beginning (zero time) all the matter and energy of the Universe was squeezed together into a ‘cosmic egg’. This cosmic egg was not very stable and therefore it exploded. This explosion was the most gigantic of all time; so big that it is very hard to imagine its real force and vigor. The fragments of the explosion became the galaxies and the stars of today. This model was popularized and further developed scientifically by the Russian-born American physicist George Gamow. Gamow called this model the Big Bang theory. In this model the Universe is expanding and the galaxies are receding from each other. Independently of the Lemaitre and Gamowmodel, the American astronomer Edwin Powel Hubble concluded in 1929 that the galaxies were receding from one another. Let’s imagine the Universe as the surface of a balloon on which certain
areas represent stars and galaxies. Between the stars is the interstellar medium. If one blows up the balloon, it expands and the distance between the stars increases. A similar picture, although geometrically more complicated, describes our Universe. There is no scientific evidence for the origin of this cosmic egg or
what happened before the explosion. The scientific evidence begins at an extremely short time after the explosion. At that time, in the beginning, everything was in a plasma state of matter. This plasma state was very bizarre and different from the one which was discussed in the previous chapter. It consisted of extremely high-energy photons and charged elementary particles. Due to the many collisions between the photons and the charged particles, as well as between the particles themselves, the photons maintained the same temperature as the other particles. The temperature was so hot that the radiation photons had enough energy to produce elementary particles. In order to understand the formation of particles in this extremely hot plasma, one needs some basic knowledge of elementary particles and the laws of conservation that govern their interactions.
