Take a virtual stroll through the gallery today. They’re all photos returned from NASA’s Juno probe’s fifth close flyby of Jupiter on Thursday, May 18 at 9 p.m. CDT. At the time of perijove — the point in Juno’s orbit when it’s closest to the planet’s center — the spacecraft skimmed just 2,200 miles (3,500 km) above Jupiter’s cloud tops. As of May 18, Juno had logged 63.5 million miles (102 million km) in orbit about the planet.
The photos are the raw images from Juno’s camera that I’ve processed to bring out color, contrast and details. Like you, I find the swirls and whorls simply mesmerizing. Jupiter not only receives heat from the sun but also gives off heat from within. The planet’s internal heat warms gas from below the cloud tops which rises and creates the distinctive cloud types and textures.
Where does all that heat come from anyway? More than 4.5 billion years ago, the cloud of gas and dust that would eventually form the planet began to contract under the pull of gravity. When material is compressed, it warms up as gravitational energy is converted into heat. If the cloud is massive, the process can build up enough heat to ignite nuclear fusion and a star is born.
Planets form from smaller clouds, but they all start out warm inside. Giant planets like Jupiter have much more mass, so their interiors are much, much hotter. It’s this heat that’s still leaking out into space from Jupiter’s interior that powers the weather systems and winds that give Jove the psychedelic patterns we all enjoy. Indeed the planet’s still contracting at the rate of 1.2 inches (3 cm) per year or 18.6 miles (30 km) per million years as its interior temperature slowly cools.
Earth is hot inside too with heat left over from its formative years, and like Jupiter is slowly cooling. But there’s a big difference between Earth’s weather systems and those on the giant planet. Ours are powered and sustained by heat from the sun, since Earth’s thick crust insulates the atmosphere from the hot, semi-molten core. Were the sun to suddenly disappear, weather as we know it would be over, while nearly half a billion miles away, Jupiter’s clouds would still burble and whorl, driven by winds in excess of 250 miles an hour (402 km/hr).