Book 1. From the Origin to the hominids

A Big Bang, i.e. a gigantic silent explosion occurred 13.5 billion years ago, with an unsustainable intensity of light and heat thrown in all directions. Light traveled during billions of years and cooled down, with the result that the Universe was getting cold, really cold. However, without cold, no galaxies, no stars and planets would form.  A tiny planet formed 4.5 billion years ago, orbiting around a star at a distance just adequate to have water neither boiling nor freezing, although it …