Mars had an oxygen-rich atmosphere around 4 billion years ago
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From the nitrogen in our DNA, to the calcium in our teeth, the iron in our blood, to the carbon in our apple pies - all were made in the interiors of collapsing stars; we're all made of stardust.
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Neil Armstrong, the first man to step foot on the moon, carried with him a piece of cloth and wood from the original 1903 Wright Flyer.
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Tidal forces between the Earth and Moon are slowing the Earth down and pushing the Moon further away.
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In the last 7 years, humanity has discovered 43 potentially habitable planets.
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Pluto is smaller than Russia.
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