How can Jupiter have no surface? A dive into a planet so big, it could swallow 1,000 Earths

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Benjamin Roulston, Clarkson University

(THE CONVERSATION)

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Why does Jupiter look like it has a surface – even though it doesn’t have one? – Sejal, age 7, Bangalore, India

The planet Jupiter has no solid ground – no surface, like the grass or dirt you tread here on Earth. There’s nothing to walk on, and no place to land a spaceship.

But how can that be? If Jupiter doesn’t have a surface, what does it have? How can it hold together?

Even as a professor of physics who studies all kinds of unusual phenomena, I realize the concept of a world without a surface is difficult to fathom. Yet much about Jupiter remains a mystery, even as NASA’s robotic probe Juno begins its ninth year orbiting this strange planet.

First, some facts

Jupiter, the fifth planet from the Sun, is between Mars and Saturn. It’s the largest planet in the solar system, big enough for more than 1,000 Earths to fit inside, with room to spare.

While the four inner planets of the solar system – Mercury, Venus, Earth and Mars – are all made of solid, rocky...