The big bang

It is now generally agreed among both astronomers and physicists alike that the Universe was created some 10 to 20 billion years ago in a leviathan explosion dubbed the "Big Bang". This cataclysmic event resulted in the production of light in the form of "photons", matter in the form of leptons (electrons, positrons, muons) and baryons (protons, antiprotons, neutrons, antineutrons), as well as the subsequent formulation of the Universe's first chemical elements.

The concept of the Big Bang was not immediately obvious to astro-physicists, but rather grew out of a steady culmination of evidence gathered from both theoretical and observational parameters throughout the course of the 20th century. A panopoly of theories attempting to explain the origin of the Universe were eventually discredited and superseded by the Big Bang hypothesis based upon the following critical considerations:

the current expansion, or Hubble flow, of the Universe.
the observed helium and deuterium abundances.
the cosmic background micro-wave radiation.
the cosmological solutions of Einstein's equations.
agreement between various independent age estimates of the Universe.

Bibliography.

Emad Iskander