History of the Earth

By MonikaMidd
  • 100,000 BCE

    Planetary Accretion

    Our Solar System was a disk of dust and gas in orbit around the proto-Sun. The solid materials collided with each other and grew to form gradually larger bodies, until the Solar System's four terrestrial planets (Mercury, Venus, Earth, and Mars) were formed.
  • Period: 100,000 BCE to 10,000 BCE

    Formation of Planets and Planetismals

    When our sun was formed, it sent out stellar winds, which were so strong that they blew the off most of the gases of the four planets closest tot eh sun, leaving them to be smaller. The four outer planets were so far away they kept their gas and they has a small rocky core. Even though there were asteroids, no other planet formed because of Jupiter's gravity.
  • Period: 10,000 BCE to 1000 BCE

    Formation of the Moon

    A small contending planet, about one-tenth the size of Earth, collided with Earth and then it was still red-hot beneath a possible thin new crust. Some of the material from the impact was absorbed into the liquefied Earth but some material ricocheted into space, where it settled into orbit and condensed as the Moon. This impact cause the Earth to tilt on its axis, creating the seasons and the Earth used to take 12 hour to complete a rotation on its axis, but now it takes 12.
  • Period: 1000 BCE to 400 BCE

    Late Accretion & Formation of Earth's Core

    Meteorite collisions, radioactive decay and planetary compression made Earth become hotter and hotter. After a few hundred million years the temperature of Earth reached 2,000C - the melting point of iron - and Earth's core was formed. These comets colliding with Earth released water and gases at the surface.
  • Period: 200 to 1 CE

    Adaptation of the Earth & Forward

    Earth's early atmosphere didn't contain much oxygen. Nonetheless, the atmosphere and oceans enabled life to get a foothold, and the first single-celled organisms evolved. Gradually these algae changed the composition of Earth's atmosphere, munching their way through carbon dioxide and water, and releasing oxygen. By about 2.5bn years ago significant amounts of oxygen had built up in Earth's atmosphere. The scene was set for complex life to evolve.
  • Period: 400 to 200

    End of Heavy Bombardment

    The forces heating up the Earth eventually stop, which allows the Earth to start cooling down. At this point much of the Earth was molten and there may have been a magma ocean at the surface. Gradually the Earth cooled and the planet settled out into a core, mantle and crust. This layering of the planet helped to trigger plate tectonics at the surface