There are 5 to 10 times more stars in the known Universe than there are grains of sand on all the world's beaches, but a single grain of sand has more atoms than there are stars in the known Universe.
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Mars had an oxygen-rich atmosphere around 4 billion years ago
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On Titan, Saturn's largest moon, the atmosphere is so thick and the gravity so low that humans could fly through it by flapping "wings" attached to their arms.
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According to a study by the National Science Foundation, only half of Americans believe in evolution, and one in 4 don't know that the Earth orbits the Sun.
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