Stephen Hawking once tried to find potential time travellers by throwing a party and only sending out invitations after the party.
17
Approximately 70 percent of the earth is covered by water. Only 1 percent of this water is drinkable.
65
Indoor pollution is 10 times more toxic than outdoor pollution.
62
At room temperature, the average air molecule travels at the speed of a rifle bullet.
55
Diamonds can be shattered with a hammer.
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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!
21