The History of the Earth

By Grace Fung
  • 4600 BCE

    Start of Solar System

    In the beginning, our solar system started as a cloud of hydrogen, helium, and dust that moved around the galaxy. At some point, a nearby star(supernova) exploded and sent a shock wave, which caused the cloud to gravitationally collapse. when the cloud collapsed, most of the mass became concentrated in the middle, which formed the sun. the smaller concentrations of mass rotating around the center formed the planets including Earth.
  • Period: 4600 BCE to 4590 BCE

    Primary Accretion Stage

    The dust is colliding into each other and creating little clumps. Around 10 million years passes, and the inner part of the solar system has rocky planetesimals becoming planet embryos. Whereas the outer planets are becoming much bigger, because its colder out there so when the dusts and clumps hit each other, they attach more easily. Thus, things are more efficient, so they grow bigger.
  • Period: 4590 BCE to 4500 BCE

    Giant Impact Stage

    Much larger objects start colliding with each other. The planetesimals are forming and becoming the planets that we know. With roughly 4 rocky planets in the interior. On the exterior, 2 gas giants, Jupiter and Saturn and 2 ice giants Uranus and Neptune. During this period, the moon was also formed.
  • Period: 4530 BCE to 4530 BCE

    Formation of the Moon

    An asteroid the size of mars crashes into Earth and knocks some debris off of it. The huge amount of energy from the impact melted most of Earth, as well as the asteroid. Materials from both were thrown into orbit. Over time, the material smashed together to form the moon. The collision happened around 70 million years after Earth formed.
  • Period: 4500 BCE to 4000 BCE

    Late Accretion Stage

    Pluto-like objects crashed into Earth and the other planets, depositing metal at the surface in the process.
  • Period: 4500 BCE to 4500 BCE

    Formation of Earth’s Core and Crust

    The collisions made Earth really hot and it began melting. The denser material sank to the bottom, while the lighter substances rose to the top. The volcanoes released gases that formed the atmosphere.
  • Period: 4000 BCE to 3800 BCE

    Late Heavy Bombardment

    The planets Jupiter and Saturn migrated towards inner planets, cleared out a lot of rock and migrated back out. During this period, other things could have hit Earth, like comets carrying water, which would explain existence of water on Earth.
  • Period: 3800 BCE to 3800 BCE

    End of Heavy Bombardment

    The heavy bombardment stage ends.
  • Period: 3000 BCE to 3000 BCE

    Planetary Cooling

    Earth begins to cool down and all of the heat in the Earth’s core attempts to escape. As the heat tried to escape, it broke up the Earth’s surface and created tectonic plates and magnetic fields.