Brown Dwarfs: Crash Course Astronomy #28
While Jupiter is nowhere near massive enough to initiate fusion in its core, there are even more massive objects out there that fall just short of that achievement as well called brown dwarfs....
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The sky, we now know, is full of stars AND planets. Stars are massive enough to fuse hydrogen into helium in their cores, generating energy. The heat created by that process tries to expand them, but their gravity balances that outward force, creating an equilibrium. Planets, even gas giants like Jupiter, are far too small to generate fusion. The stuff inside them resists being squeezed, so their gravity is balanced by simple gas pressure. Jupiter is only about 1% the mass needed to have fusion going on in its core. That’s a pretty big gap between a big planet and a small star. It’s natural to ask what would happen if we dumped more mass onto Jupiter. Eventually it would become a star -- the pressure in its core would get high enough to initiate hydrog...
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The sky, we now know, is full of stars AND planets. Stars are massive enough to fuse hydrogen into helium in their cores, generating energy. The heat created by that process tries to expand them, but their gravity balances that outward force, creating an equilibrium. Planets, even gas giants like Jupiter, are far too small to generate fusion. The stuff inside them resists being squeezed, so their gravity is balanced by simple gas pressure. Jupiter is only about 1% the mass needed to have fusion going on in its core. That’s a pretty big gap between a big planet and a small star. It’s natural to ask what would happen if we dumped more mass onto Jupiter. Eventually it would become a star -- the pressure in its core would get high enough to initiate hydrog...
