Water
Where did water come from?
Water's hydrogen comes from the Big Bang and its oxygen from stars; Earth's water may have come partly from the rocks that built it and partly from meteorites.
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In three stops
Where were its atoms born?
Water's hydrogen comes from the Big Bang and its oxygen from inside stars. The two combine as ice in cold clouds of gas and dust in space; water is one of the most common molecules in the universe.
How did it form on Earth?
Some of Earth's water was locked inside the rocks that built it, and some may have arrived with meteorites; the proportions are still debated. Crystals 4.4 billion years old show the oceans formed very early.
What did humans make of it?
All life began in water and depends on it. The first cities grew up along rivers, and farming expanded with irrigation canals. From the steam engine to the power station, water also became a basic material of industry.
Did you know?
About 60% of your body is water. A single glass of water contains more molecules than there are glasses of water in all the world's oceans.
See it in the journey: The first oceans (4.4 billion years ago) →