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Planetary Accretion
Around 4.6 billion years ago, the solar system was simply a cloud of dust and gas. However, gravity collapsed the material in on itself as it began to spin, forming the sun in the center of the nebula. -
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Formation of The Moon
Around 4.5 years ago, the moon was created. This happened when leftover debris collided with Earth, thus forming the moon. -
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Planetary Cooling
Around 4 billion years ago, the Earth began to cool. This event means the magma that made up the Earth began to harden and form its outer core and oceans. -
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End of Planetary Bombardment
Around 4.5 to 3.8 years ago, a huge amount of asteroids hit Earth and many other planets. This event was what completed their accretion. -
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Core Formation
Around 1.5 billion years ago, Earth's core was formed. This happened when it froze from the surrounding molten iron outer core, which is also made of nickel. Despite being very hot, Earth's interior is cooling around 100 degrees Celsius per billion years.