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13 BCE
Planetary Accretion
A few hundred thousand years after the Big Bang, the Universe cooled to the point where atoms could form. As the Universe continued to expand and cool, the atoms lost enough kinetic energy, and dark matter coalesced sufficiently, to form protogalaxies. As further accretion occurred, galaxies formed. Indirect evidence is widespread. Galaxies grow through mergers and smooth gas accretion. Accretion also occurs inside galaxies, forming stars. -
13 BCE
Planetary Accretion
A few hundred thousand years after the Big Bang, the Universe cooled to the point where atoms could form. As the Universe continued to expand and cool, the atoms lost enough kinetic energy, and dark matter coalesced sufficiently, to form protogalaxies. As further accretion occurred, galaxies formed. Indirect evidence is widespread. Galaxies grow through mergers and smooth gas accretion. Accretion also occurs inside galaxies, forming stars. -
4 BCE
Planetary Cooling
About 4.5 - 3.8 billion planetary cooling formed the planet into a molten planet. Clumps of asteroids,meteors,and comets helped formed the planet into a shpere. There were volcanic eruptions as well which contained magma . The magma then hardened which created Earth's outer core. -
4 BCE
Formation of the moon
Scientists think the moon arose a short time later than the earth. The leading explanation for the moon's origin, known as the Giant Impact Hypothesis, was first proposed in the 1970s. -
3 BCE
End of Heavy Bombardment
About 4 to 3.8 billion years ago a period of intense comet and asteroid bombardment is thought to have peppered all the planets including the Earth. Many of the numerous craters found on the Moon and other bodies in the Solar System record this event. -
1 BCE
Core formation
here have been many estimates for when the earth's inner core was formed, but scientists have used new data which indicates that the Earth's inner core was formed 1-1.5 billion years ago as it 'froze' from the surrounding molten iron outer core.
