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Caption: Where did Earth’s water come from? More than 70% of Earth is covered in water… but where did it actually come from? For years, the simple textbook answer was th… more Where did Earth’s water come from? More than 70% of Earth is covered in water… but where did it actually come from? For years, the simple textbook answer was this: Earth started out dry, and water was delivered later by icy space rocks crashing into it. But modern science suggests the story is far more interesting. Astronomers usually group the ideas into two main camps. First: water delivered from space. At first, scientists thought comets were the main source of Earth’s water. But when we studied them up close, their water had a slightly different chemical fingerprint than our oceans. So attention shifted to carbonaceous chondrites — a type of asteroid whose water chemistry matches Earth’s much more closely. But there’s a second possibility… What if Earth wasn’t dry to begin with? Studies of rare meteorites similar to the material that formed Earth show they contain plenty of hydrogen — potentially enough to create three times the water in Earth’s oceans. In that scenario, water was trapped inside Earth’s minerals from the beginning. As the young planet heated up and volcanoes erupted, water vapour escaped into the atmosphere… eventually cooling, condensing, and falling as rain that filled the oceans. But these explanations aren’t competing. Most scientists think Earth’s oceans are a cosmic cocktail — mostly from the rocks that built our planet, with a splash from icy visitors later. So the next time you take a sip of water… You’re drinking ancient Earth — and a little bit of deep space. @sydneywater #Water #PlanetaryScience #SpaceFacts #Astronomy #SolarSystem less
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