Jupiter Needs to Be 80 Times Heavier to Become a Star

Jupiter is sometimes called a failed star. To succeed, it would need to be eighty times heavier.

Imagine Jupiter igniting. Our biggest planet is a giant ball of hydrogen, the same fuel that powers the Sun. It has the right ingredients, just not nearly enough.

To fuse hydrogen and shine as a true star, a ball of gas must be crushed by its own gravity until the core hits about ten million degrees. That takes serious mass. Jupiter would need eighty times its current mass to cross that line. Even at thirteen times its mass, it would only smolder as a dim brown dwarf, never truly igniting. Reach the full eighty, and Jupiter would spark into the smallest kind of real star, a faint red dwarf. Our solar system would suddenly have two suns.

In that world, true night would nearly vanish. For part of the year, a second star would hang in our sky, and darkness would become rare.

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