Mickey Mouse Meets Jupiter

Amateur astronomers have been keeping watch over the “Mickey Mouse” ovals this observing season. The ovals are smaller-scale storms – the ‘nose’ rotates clockwise similar to a low pressure system in our planet’s southern hemisphere; the ears are high pressure center rotating counterclockwise. South is up. Credit: Damian Peach

This observing season, three of Jupiter’s many storms – called white ovals – happen to resemble the face of the famous Disney character Mickey Mouse. Two ears and a big nose. Just like Mickey, they might be up to mischief.

Jupiter has lots of these white ovals and brown ones, too. They’re hurricane-like storms in the planet’s atmosphere similar to but smaller than the behemoth Great Red Spot. Most don’t have names unless they’re around a long time or expand and merge with other ovals.

Like four little piggies in a row, four nameless white ovals appear near the Great Red Spot in this photo taken Dec. 29, 2013. South is up. Credit: Damian Peach

The white variety are swirling vortices of cold ammonia ice clouds high in the upper atmosphere. Astronomers find them at many locations tucked within the planet’s cloud belts. Brown ovals are holes in Jupiter’s cloud deck that let us peer deeper into the warmer atmosphere below. They typically only appear within a few degrees of the 20 degree north latitude zone.

The Hubble Space Telescope recorded the merger of three separate ovals in the mid-1990s into Oval BA a.k.a. Red Spot Jr. Notice a similar Micky Mouse shape prior to the merger. Credit: NASA/ESA

Back in the late 1930s, a bright white band of clouds appeared along Jupiter’s 30 degree south latitude zone and eventually coalesced into three separate counterclockwise spinning ovals named FA, DE and BC.

Red Spot Jr. rides Jupiter’s South Temperate Belt on March 7, 2014. South is down. Credit: Christopher Go

In the late 1990s the trio gradually met up merged into a single larger oval named ‘BA’ about as wide as the Earth around 2000. Five years later it developed a reddish-orange color, inspiring amateur astronomers to nickname it Red Spot Jr. The feature, now more circular than oval, still cycles around the planet to this day. Its color, like that of the Great Red Spot, is believed to come from the mixing of sulfur, carbon and phosphorus compounds sucked up from the lower atmosphere.

Zones, belts and vortices on Jupiter. The two most prominent dark stripes are the North and South Equatorial Belts. You can also see the Great Red Spot and many small white ovals. This 14-frame animation spans 24 Jovian days, or about 10 Earth days. The passage of time is accelerated by a factor of 600,000. Credit: NASA

The Great Red Spot (GRS) is one of the biggest storms in the solar system with wind speeds up to 400 mph (650 km/hr). Currently about 1.5 Earths wide,  it’s persisted for several centuries. For all we know it too resulted from a long-ago merger.

Coincidentally, you can see it late tonight across the Americas. The Spot sits squarely on the planet’s centerline around 12:30 a.m. CDT March 29 (1:30 a.m. Eastern, 10:30 p.m. Pacific). If that’s too late, you can start looking about 1-1/2 hours before these times when it will be to the east of centerline. Click HERE to find the best times for viewing the storm from your city.

A large brown oval is known was imaged by Voyager 1 on 2 March 1979. It’s 6,200 miles (10,000 km) across. Amateur astronomers often refer to large brown ovals as “barges”. Click to enlarge. Credit: NASA

Jupiter’s all weather all the time. Ovals change shape, push each other around and even merge. While you might strain to see white ovals or even Red Jr. in the telescope, make no mistake, these are big storms by earthly standards. Mickey Mouse’s ears are about one-third the width of the GRS or approximately half as big as our planet. I wouldn’t want to get close to that hurricane!

2 Responses

  1. Sean

    One comment: Under the 1st photo the caption mentions how the “nose” rotates clockwise like a low pressure system in the US. Well, low pressure systems here DO move clockwise – if seen from underneath. However, from the usual perspective of “from above”, they rotate counterclockwise, with the high pressure systems here rotating clockwise from that perspective. Of course, in the S hemisphere, this is opposite. So are we viewing a N-S inverted image of Jupiter, which would explain the differences in rotation vis-a-vis pressure, or is the pressure status of those storms mislabeled? i’m pretty sure Jupiter doesn’t rotate E to W which would cause the N-hemisphere pressure systems there to do what the S-hemisphere ones here do.

    1. astrobob

      Hi Sean,
      You are correct and thank you for pointing out the error. The southern hemisphere in the “Mickey Mouse” panel is at top, so the lows and highs rotate in the opposite direction from the northern hemisphere. The spin directions shown for the highs and low in the photo panel are correct.

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