The oldest stone tools found are dated from 2.7 - 2.9 million years ago. The species that made these tools is unknown.
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In the last 7 years, humanity has discovered 43 potentially habitable planets.
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An unprotected human can survive up to 1.5 minutes in space with no permanent bodily damage.
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A lump of pure gold the size of a matchbox can be flattened into a sheet the size of a tennis court.
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The focusing muscles of the eyes move around 100,000 times a day. To give your leg muscles the same workout, you would need to walk 80km (50 miles) every day.
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