Where did all the water in the universe come from? (Intermediate)

Hi, water water everywhere--but where did it come from? Our solar system is made of star stuff, did our water form during a super nova? Can H2O exist in stars?

No, H2O cannot exist in stars, but H and O separately can. Hydrogen is the basic building material of the universe, created in the Big Bang. Oxygen is created by nuclear reactions in stars. If you put H and O together in the cold of space, you get H2O. There are enormous amounts of water in space. In fact, nearly all of the oxygen in space is in the form of water or carbon monoxide. Similarly, most the carbon and nitrogen in space are also in their most hydrogenated forms: methane (CH4) and ammonia (NH3).

About the Author

Dave Kornreich

Dave was the founder of Ask an Astronomer. He got his PhD from Cornell in 2001 and is now an assistant professor in the Department of Physics and Physical Science at Humboldt State University in California. There he runs his own version of Ask the Astronomer. He also helps us out with the odd cosmology question.

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