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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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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One 75-watt bulb gives more light than three 25-watt bulbs.
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Aluminum used to be more valuable than gold!
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One cubic foot of gold weighs more than 1,200 pounds!
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