periodic table of astronomy

10

What Is The Universe’s Third Most Common Element?

“But there’s one killer move that stars have that makes carbon a loser in the cosmic equation: when a star is massive enough to initiate carbon fusion – a requirement for generating a type II supernova – the process that turns carbon into oxygen goes almost to full completion, creating significantly more oxygen than carbon by time the star is ready to explode.”

When the Universe was first born, all we had was hydrogen and helium, with a trace amount of lithium and absolutely nothing else. 13.8 billion years later, hydrogen is still #1 in the Universe and helium is still #2, but lithium isn’t close to #3 anymore: more than two dozen elements have passed it. The key? Stars! Over billions of years, nuclear fusion in the cores of stars have built up all the naturally occurring elements we know of in the periodic table. You might think that since three heliums can fuse together to make carbon, that would be the third most common element in the Universe. And it’s close: carbon comes in at #4. But another element has it beat.

So who’s number 3, and how did it get to be that way? It’s oxygen! Find out why today.