Fig13

Earth's History Timeline

By Linie Cha
  • 4600 BCE

    Birth of Sun

    Birth of Sun
    Solar system started as a gas cloud and stardust that moved around the galaxy (hydrogen, helium, and dust)some point, star nearby exploded called SUPERNOVA. This explosion sent a shock, destabilizing and increased rate of rotation. The ripple caused the gas to gravitationally collapse into swirling disk: forming Sun which ignited (molecules crashed together the tightest in center) and a protoplanetary disk around it.
  • Period: 4600 BCE to 4596 BCE

    Primary Accretion Stage

    During the 1st hundred thousand years, dust collides into each other (gravity, materials at similar distance from Sun), creating little clumps, rocks or CONDRULES. By the end, a kilometer sized rock is enough to accrete or gather additional material allowing it to grow and continue for 10 million years
    • Inner part of solar system: rocky planetesimals-->planet embryos
    • Outer planets: becoming much bigger. Colder so that when the dust and clumps hit each other, attach more easily
  • Period: 4600 BCE to 4000 BCE

    Hadean Eon

    Hadean Eon (4.6 billion and about 4.0 billion years ago) is characterized by Earth’s initial formation—from the accretion of dust and gases, and the frequent collisions of larger planetesimals, then by the stabilization of its core and crust and the development of its atmosphere and oceans. At this point, impacts from extraterrestrial bodies released enormous amounts of heat that likely prevented much of the rock from solidifying at the surface.
  • Period: 4596 BCE to 4500 BCE

    Giant Impact Stage

    Next 100 million years—much larger objects collide with each other; planetesimals really forming the real planets (4 rocky planets INTERIOR, two gas giants: Jupiter and Saturn, two ice giants: Uranus and Neptune.
    70 million years after EARTH, MOON was formed
    HOW…? Object, size of Mars crashed into Earth, knocks debris, hot molten goop stays in orbit around Earth, cools into spherical object.
  • 4570 BCE

    Formation of Earth

    Formation of Earth
    Earth formed like the other planets. Different materials in its region of space collided. All of the collisions caused Earth to heat up. The molten material separated into layers. Gravity pulled the denser material into the center. The lighter elements rose to the surface (Figure below). Because the material separated, Earth’s core is made mostly of iron. Earth’s crust is made mostly of lighter materials. In between the crust and the core is Earth’s mantle, made of solid rock.
  • 4500 BCE

    Formation of the Moon

    Formation of the Moon
    HOW?
    In the early solar system, there was a lot of space debris. Asteroids flew around, sometimes striking the planets. An asteroid the size of Mars smashed into Earth. The huge amount of energy from the impact melted most of Earth, and the asteroid itself. Material from both Earth and the asteroid was thrown out into orbit, and this smashed together to form our Moon.This means that the collision happened about 70 million years after Earth formed.
  • Period: 4500 BCE to 4200 BCE

    Late Planetary Accretion Stage

    Pluto like objects crashing into Earth and to other planets, and deposited metal (stayed at surface rather than sinking towards the center). This is the metals we see today.
  • Period: 4200 BCE to 3500 BCE

    Late Heavy Bombardment

    This is the time period where a lot of violence occurred with heat. Jupiter and Saturn migrated their way towards the inner planets, and cleared out a lot of more of rocks and asteroid belt (towards the sun), then migrated back out. Other interesting things: comets carrying water might have hit the Earth, showing the existence of water on our planet today.
  • Period: 3500 BCE to 1900 BCE

    Planetary Cooling

    Following 1.6 billion years, all heat in core tries to escape Earth with additional radioactive elements are heating it even more. Heat tried to escape, which formed solid crust breaking up continents (surface/ tectonic plate). Volcanoes releasing gas, formed new atmosphere (containing ammonia, methane, water vapor, carbon dioxide, little trace of oxygen). As the atmosphere become dense, clouds formed & rains fell. Rain+ comets and asteroids struck Earth, and created the OCEAN
  • 1500 BCE

    Formation of the Earth's Core

    Formation of the Earth's Core
    Earth's inner core was formed 1-1.5 billion years ago.