Nature
An octopus has three hearts.
Two send blood to the gills. The third sends it around the rest of the body.
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Radio helped save the Eiffel Tower.
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Science
Sound travels faster underwater.
In seawater, sound moves more than four times as fast as it does in air.
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People were teaching at Oxford in 1096.
Oxford’s earliest evidence of teaching goes back more than nine centuries.
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Space
Venus spins slower than it orbits.
Venus takes about 243 Earth days to spin once, and 225 to go around the Sun.
Read the factTechnology
The first website explained the Web.
Tim Berners-Lee used the first site to explain what the Web was and how to use it.
Read the factSpace
Jupiter spins once in under 10 hours.
The largest planet in the solar system also has the shortest rotation period.
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Water takes up more space when it freezes.
Ice floats because the same mass takes up more space as a solid.
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Lightning can heat air to about 28,000°C.
A strike heats the surrounding air so quickly that it expands and makes thunder.
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A surviving printed book is dated to 868.
The Diamond Sutra is the earliest known complete printed book with a date.
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Radio helped save the Eiffel Tower.
Its original land-use permit lasted 20 years. Wireless telegraphy gave Paris a reason to keep the tower.
Read the factSpace
A solar day on Mercury lasts about two Mercury years.
One sunrise-to-sunrise cycle takes about 176 Earth days. One orbit takes about 88.
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A year on Neptune lasts about 165 Earth years.
Neptune finished its first orbit since its 1846 discovery in 2011.
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Nature
About half of Earth’s oxygen production happens in the ocean.
Much of the world’s oxygen production comes from tiny organisms near the ocean surface.
Read the factNature
A shark’s skeleton is made of cartilage.
Sharks share this lighter skeleton with rays and skates.
Read the factTechnology
GPS has to account for Einstein’s relativity.
Without corrections, GPS satellite clocks would gain about 38 microseconds a day relative to clocks on Earth.
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The QR code was introduced in 1994.
DENSO WAVE designed the square code to hold more data and scan quickly.
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Health
Your brain stays active while you sleep.
During REM sleep, brain waves look more like they do when you’re awake.
Read the factHealth
Skin is your body’s largest organ.
Adult skin covers about 1.7 square metres on average.
Read the factHealth
Your bones are living tissue.
Specialised cells break down old bone and build new bone throughout your life.
Read the factHealth
Your kidneys filter blood every minute.
Healthy kidneys filter about half a cup of blood a minute.
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