During photosynthesis, plants emit light humans can’t see, but NASA can see that light from space - and they've even made maps of it!
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Nearly 50% of the world's scientists are assigned to military projects.
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Optical illusions occur when what the eyes see conflicts with what the brain expects.
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Stephen Hawking once tried to find potential time travellers by throwing a party and only sending out invitations after the party.
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Sound at the right vibration can bore holes through a solid object.
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Only 12,000 years ago there was a species closely related to modern humans called Homo floresiensis that had been living on an Indonesian Island. They used fire and rather advanced tools, yet were only about 3 feet tall and weighed around 25kg.
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In zero gravity, a candle's flame is round and blue.
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