Jupiter's Great Red Spot Is Shrinking

"Every time we look at Jupiter, we get tantalizing hints that something really exciting is going on."


Mars and Pluto are getting all the good news lately, but there are other planets in the solar system, people! For instance, Jupiter — the size of more than 1,000 Earths — is still hanging around. On Tuesday, NASA scientists released new global maps of Jupiter as the first in a series of annual cartographical portraits of the other planets orbiting the sun.

The maps, also described in a new paper published in the October issue of The Astrophysical Journal, were designed using images snapped by the Hubble Space Telescope, under the Hubble 2020: Outer Planet Atmospheres Legacy program. In a press release, NASA describes the program as “the planetary version of annual school picture days for children.”

But the maps aren’t simply a fun project to show how fast the little planets are growing. They’re also an invaluable way of tracking surface and atmospheric changes on the outer solar system planets.

The latest maps of Jupiter confirm that the Giant Red Spot is shrinking fast into a Medium Red Spot. The long axis of the massive storm is 150 miles shorter than it was last year.

The changes in Jupiter's Giant Red Spot.


In addition, in Jupiter’s North Equatorial Belt, the maps illustrate a new wave that had previously been seen only by Voyager 2 many years ago. These “baroclinic waves” are associated with the formation cyclones.

The wave spotted in Jupiter's North Equatorial Belt


“Every time we look at Jupiter, we get tantalizing hints that something really exciting is going on,” said Amy Simon, a planetary scientist at NASA’s Goddard Space Flight Center. “This time is no exception.”

Next up in the OPAL program will be maps of Neptune and Uranus, with Saturn being added to the series later. It’s a wonderful last hurrah for the Hubble Space Telescope, whose role will be soon usurped by the more powerful James Webb Space Telescope launching in 2018. Hubble will still be around of course, and perhaps it can keep helping out with these annual planet portraits for several more decades.