General Science

The Latest News About Jupiter’s Great Red Spot

posted: 07/13/17
by: Jason Ginsburg

It's the most famous storm in the solar system and it has captivated the science community and the public for centuries. It's the Great Red Spot.

As dazzling as the planet's multi-colored cloud bands are, it's hard not to be drawn to the giant red eye in Jupiter's southern hemisphere. Since observations began in 1665, we've wondered just what was happening inside this massive storm.

Humanity would have to wait until 1979, when both Voyager 1 and Voyager 2 flew past the planet, giving us the first close-up looks at the swirling Spot and the swirling clouds around it. Galileo followed in 1995, becoming the first craft to orbit Jupiter, and imaged the Spot at different wavelengths.

Since then, passing probes and the Hubble Space Telescope have taken more and better photos of the massive tempest. In 2014, NASA made a startling announcement: The Great Red Spot had shrunk to its smallest size ever -- 10,250 miles across. That's still large enough to fit two entire Earths inside, but it marks a huge decline from historical observations.

Jupiter's Great Red Spot, via Juno

NASA / JPL-Caltech / SwRI / MSSS / Roman Tkachenko

Astronomers in the 1800s estimated the long axis of the Spot to be 25,000 miles across. The Voyager 1 and 2 flybys found it be 14,500 miles. A Hubble photo from 1995 showed the long axis to be about 13,000 miles. Not only is the Spot smaller now, but it has changed from an oval to a circle. The theory is that eddies have entered the storm system, "altering the internal dynamics and energy of the Great Red Spot," according to NASA scientist Amy Simon.

Another recent discovery about the Spot is that it's heating up the rest of Jupiter. The storm spins counter to the other clouds in the atmosphere, causing collisions between the Spot's gravitational and acoustic waves, which generates heat. In fact, temperatures in the planet's upper atmosphere can reach 2,370 degrees Fahrenheit -- hotter than molten lava. This is surprising, considering the planet is three times farther from the sun than Mars is, where average temperatures barely get above freezing.

In a way, serious Jupiter exploration is only beginning. Juno, which arrived at the planet in July 2016, has just completed its sixth "perijove," the probe's closest approach during its 53-day orbit. The flyby brought the probe 5,600 miles from the Great Red Spot, giving us awe-inspiring images of the giant storm's power and beauty.

Science Channel will keep watching as pictures and data from Juno's latest encounter arrive. Until then, learn more about the Great Red Spot.

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