Mars had an oxygen-rich atmosphere around 4 billion years ago
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There is a mass reservoir of water floating in space that is 100,000 times bigger than our sun and holds 140 trillion times more water than all of our oceans.
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Cows can sleep standing up, but they can only dream lying down.
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The oldest stone tools found are dated from 2.7 - 2.9 million years ago. The species that made these tools is unknown.
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Only about 2% of the world population has green eyes.
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The University of Oxford (teaching since 1096) predates the Aztec empire (1428 - 1521).
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