Jupiter has a bulging waistline. The planet is almost 6,000 miles thicker through the equator than through the poles — the result of diet and activity.

Jupiter is the largest planet in the solar system. It’s 11 times the diameter of Earth, and more massive than all the other planets combined.

Jupiter grew so large because it was born far from the Sun. At that distance, it was cold enough for the planet’s growing center to incorporate a lot of ice in addition to rock, so it grew big and heavy. And that gave it a strong gravitational pull.

Jupiter used that gravity to suck in a lot of hydrogen and helium gas that were left over from the birth of the Sun — gas that wasn’t available closer to the Sun. Hydrogen and helium are the lightest of all chemical elements, so while they helped make Jupiter big, they didn’t make it very dense.

And Jupiter spins on its axis faster than any other planet — one turn in less than 10 hours. That high-speed rotation pushes the lightweight hydrogen and helium gas outward. And that gives the giant planet a giant waistline.

That equatorial bulge is easy to see through a telescope — Jupiter definitely looks squished.

You can’t see the bulge with the eye alone, but Jupiter itself is especially easy to pick out tonight. It stands close above the Moon at nightfall. And it looks like a brilliant star. In all the night sky right now, only the Moon outshines it.

Script by Damond Benningfield

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