We talk a lot on this show about stars. But where do they actually come from? Host Patrick McNameeKing put the question to John Gianforte, an astronomer at the University of New Hampshire.
Born in a cloud
According to Gianforte, the story begins in nebulae — vast clouds of gas and dust, mostly hydrogen, drifting through space. Within those clouds, mass concentrates in uneven patches. Where enough material gathers, gravity takes over: The cloud begins to collapse inward, pulling in more and more of its surroundings.
If conditions are right and enough mass accumulates, temperatures at the core climb until something remarkable happens: Nuclear fusion ignites. At that moment, Gianforte says, "a star is actually born."
Sometimes two collapsing regions form close enough together to become a binary system, or even a triple star.
Jupiter: The star that almost was
"It's sometimes said in astronomy textbooks that Jupiter is a star that failed," says Gianforte. "I guess if you're a proponent of stars, you could say that it failed. But if you like planets, you could say that it succeeded."
Had Jupiter been born with about 80 times more mass, it likely would have kept collapsing past the point of being a planet, eventually igniting as a low-mass star.
Are you Cosmically Curious? Shoot us your questions about the night sky at Cosmic@nhpr.org.
