#jupiter exploration

Finally, in November researchers got what they were waiting for — a new storm had formed and edged its way into a gap, forming a stable and symmetrical hexagon.

Juno’s infrared imager, known as the Jovian Infrared Auroral Mapper (JIRAM), captured the cyclonic dance:

Planetary observing forums are abuzz this week with talk of interesting happenings on the gas giant. The planet is already known to be in the midst of a rare Equatorial Zone (EZ) clearing event, as the normally white EZ has changed color to a brownish tan. Now, the Great Red Spot (GRS) is competing for attention, thanks to an unusual interaction with its neighboring South Equatorial Belt (SEB).

Planning observations for the Juno spacecraft at Jupiter is a group effort, and Candice Hansen (Planetary Science Institute) should know. As the scientist in charge of JunoCam — one of the cameras onboard the probe — she spends a lot of time chatting with professional and amateur astronomers, keeping tabs on what’s happening in Jupiter’s turbulent atmosphere. Their intel is critical to figuring out where to point JunoCam each time the spacecraft makes another close pass over the planet.

But lately, this worldwide network of backyard Jupiter enthusiasts has been helping mission scientists figure out where precisely Juno should fly. Speaking last week at a meeting of the American Geophysical Union in Washington, D.C., Hansen described how Juno’s army of amateurs were key players in deciding whether or not to go ahead with an impending flyover of Jupiter’s Great Red Spot.

Juno, which has been in a polar orbit since July 2016, is about halfway through its mission to map out Jupiter’s deep interior. The spacecraft spends most of its time far from the planet, but once every 53 days, it comes in low and fast, zipping from north pole to south pole in roughly 2 hours. Near the equator, the probe hurtles along at roughly 250,000 kilometers per hour (150,000 mph) just a few thousand miles over the cloud tops.

For each of these close approaches, mission scientists can tweak Juno’s speed to control precisely what longitudes it will fly over. While planning the spacecraft’s eighteenth flyby — referred to as perijove 18 in mission parlance — scientists realized they had a chance to make a second pass over the Great Red Spot if they swapped the original plan for perijove 18 with the plan for perijove 23.

After the discovery of Jupiter's four Galilean satellites in 1610, astronomers struggled to find 10 more in the 3½ centuries that followed. Today the IAU's Minor Planet Center announced that a search team led by Scott Sheppard (Carnegie Institution for Science) has identified 10 new moons of Jupiter, bringing the known total to 79 — the most of any planet in our solar system. Of those, Sheppard has led the searches that discovered 51 of them.

Dozens of Jupiter's moons circle the planet in a swarm of distant orbits and travel in a retrograde direction, that is, opposite that of the planet's spin. Their orbits cluster in three groups of 15 to 20 objects, named for members Ananke (discovered in 1951), Carme (1938), and Pasiphae (1908). Most likely each of these moonlet "families" represent fragments of larger precursors that were shattered by collisions early in Jupiter's history.