Pumice is the only rock that floats on water.
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There are more than 270 people cryogenically frozen in the hope that one day the technology will exist that can revive them and extend their lives.
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The gas that gives rotten eggs their distinctive foul smell may slow ageing and block damaging chemical reactions inside cells, according to scientists in China.
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Indoor pollution is 10 times more toxic than outdoor pollution.
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According to studies, men change their minds two to three times more often than women.
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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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Scientists have revived a flowering plant from a fruit stored away in permafrost by Arctic ground squirrel 32,000 years ago.
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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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