Category: Earth

Time: 15 Billion BC

15 Billion BC


Scientists believed that as the universe exploded following the Big Bang, it cooled rapidly and some of its energy condensed into tiny particles. Then an unexplained phenomenon called electromagnetic force putting these tiny particles together into hydrogen atoms. Gravity, another mysterious force, caused more atoms to gather. The larger these clouds of atoms, the stronger the gravitational force became, until the pressure squeezed the atoms so hard that it sparked a nuclear reaction and the clouds became huge balls of fire. Stars blinked on all over the universe. These stars burned at tremendously high temperatures as their hydrogen atoms joined to form helium atoms in a process called fusion. Small stars can burn like this for billions of years, until they run out of hydrogen. Then they cool down and collapse, becoming white dwarfs. But the largest stars burn up much more quickly, fusing these atoms together into heavier elements. Finally, they explode into supernovas, scattering new atoms of copper, gold, uranium and many other elements into the surrounding galaxy. The earth and all its plants and animals were formed from these heavier elements.


  • Sphere Big Bang: Elementary particles (electrons, protons, neutrons) form. Click to see more about the expanding universe…
  • Second "?" Element: First galaxies and quasars form. Click to see more about the expanded universe…
  • Distant elements:Stars explode and die, and other stars are born from their gas. Galaxies mature, giving us the present universe. Click to see more about the expanding universe…