What Does the Sun Burn?

sun, burn, fuel — The Sun's fire comes from a nuclear reaction burning hydrogen. (Image credit: NASA.)

For millennia, people have looked up to the sky and wondered about celestial bodies. The sparkling stars and fiery sun hold mystery and wonder. To astronomers, the sun is just another dying star, but to everyone else it’s a huge burning ball that gives heat, light, and life. So far so good.

But what is it burning? We all know that there is no air in space, and therefore no oxygen to burn. In our everyday experience, the only burning most of us are familiar with is fire combustion. But that is not the only type of reaction; the sun is indeed burning, but it is a nuclear reaction, not a chemical one.

The sun burns hydrogen — a lot of it, several hundred million tons per second. But don’t worry; there’s plenty more where that came from; by most estimates, the sun has enough fuel for about another five billion years.

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Benjamin Radford is the Bad Science columnist for Live Science. He covers pseudoscience, psychology, urban legends and the science behind "unexplained" or mysterious phenomenon. Ben has a master's degree in education and a bachelor's degree in psychology. He is deputy editor of Skeptical Inquirer science magazine and has written, edited or contributed to more than 20 books, including "Scientific Paranormal Investigation: How to Solve Unexplained Mysteries," "Tracking the Chupacabra: The Vampire Beast in Fact, Fiction, and Folklore" and “Investigating Ghosts: The Scientific Search for Spirits,” out in fall 2017. His website is www.BenjaminRadford.com.