Mars had an oxygen-rich atmosphere around 4 billion years ago
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The Sun and Moon appear to be the same size because the moon is 400 times smaller than the Sun, but 400 times closer to Earth.
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The Space Shuttle main engine weighs 1/7th as much as a train engine but delivers as much horsepower as 39 locomotives.
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An organisation called Mars One is planning to establish a permanent colony of humans on Mars by 2023.
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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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If you were to cry in space, the tears would form a bubble in your eye until it's so big it moves to another spot on your face.
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