The History of the Earth

By jennalst
  • 4600 BCE

    Birth of Sun

    The solar system began as a rotating cloud of gas and stardust. When a star nearby exploded, referred to as supernova, a shock wave was sent through the cloud. The ripple from the explosion destabilized the cloud, increased its rate of spin, and caused the gas to gravitationally collapse. As a result, the middle consisted of concentrated mass, forming the Sun and a protoplanetary disk which contained other planets.
  • Period: 4600 BCE to 4590 BCE

    Primary Accretion Stage

    Deep within the disk, clumps of dust are heated up into chondrules, droplets of molten rock by gravity and turbulence. As roughly ten million years pass, these chondrules continue to clump and grow into the first asteroids and planetesimals, eventually becoming planet embryos.
  • Period: 4590 BCE to 4500 BCE

    Giant Impact Stage

    In the next hundred million years, larger objects continue to collide into one another and planets are really coming into shape. In the interior of the solar system, 4 rocky planets form. On the exterior, two gas giants, Jupiter and Saturn, and two ice giants, Uranus and Neptune have formed. Sometime during this period, the moon was also formed.
  • Period: 4590 BCE to 4530 BCE

    Formation of Moon

    It is believed that an asteroid the size of Mars crashed into Earth, knocking debris off of it and the impact melted a large part of Earth and the asteroid. The molten debris and material from the two were thrown into orbit. Overtime, the hot molten cooled down, combined into a spherical object, and the moon was formed. The moon's lunar surface was created roughly 70 million years after the formation of our earth (Hadean Eon)
  • Period: 4500 BCE to 4000 BCE

    Late Accretion Stage

    In the next 600 million years, Pluto-like asteroids crashed into Earth and other planets, depositing metals to the surface of planets in the process.
  • Period: 4500 BCE to 4500 BCE

    Formation of Earth's Core and Crust

    Collisions made the earth heat up in which melted rocks and metals. The molten material were separated into layers by gravity; denser materials were pulled (sank) into the center (core) whereas lighter elements rose to the surface of Earth.
  • Period: 4000 BCE to 3800 BCE

    Late Heavy Bombardment

    Theories suggest that Jupiter and Saturn slowly migrated towards the inner planets, creating ripples in the asteroid belt from their large gravities and flinging asteroids towards the Sun. This process also caused other objects to hit Earth, such as comets carrying water, which created the existence of water.
  • Period: 3000 BCE to 3000 BCE

    Planetary Cooling

    Approximately 1.6 billion years after the Sun was formed, the Earth begins to cool down and all of the heat in the Earth's core attempts to escape due to the high pressure. As the heat was escaping, it separated Earth's surface into tectonic plates (continents) and created magnetic fields.