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JOIN

The Planetary Society Blog

By Emily Lakdawalla

Two storms passing on Jupiter

Jul. 21, 2006 | 09:43 PDT | 16:43 UTC

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I've been following the story of Jupiter's "Red Spot Junior," a large storm system that formed from the merger of three white spots and then, suddenly, turned red. Formally known as Oval BA, the new red spot has been creeping around Jupiter at a different rate than the Great Red Spot -- the winds in each of Jupiter's belts and zones all move at different speeds, and the storms embedded between them do too. So, sooner or later, the two storms were destined to pass, an event that culminated last week. I have to admit I'd temporarily forgotten about this story until I got a press release yesterday from the Gemini Observatory announcing a gorgeous new image of Jupiter showing the two red spots nestled close together.

Click to enlarge >

Jupiter's two red spots approach
The adaptive optics-equipped Gemini telescope snapped this view of Jupiter on the night of July 13, 2006. The images were taken in near-infrared wavelengths, in which the "red spots" show up as white. For several months, the smaller of the two red spots (known as Oval BA) has been approaching the Great Red Spot, and is here passing it to the south. The fact that Oval BA is nearly as bright as the Great Red Spot in infrared wavelengths suggests that its elevation approaches that of the Great Red Spot, whose clouds soar 8 kilometers (5 miles) above neighboring cloud bands. Credit: Travis Rector, Chad Trujillo, and the Gemini ALTAIR adaptive optics team

The writeup on the Gemini website has a lot of interesting information in it. One fun technical detail is that the adaptive optics system requires a point light source to be present in the frame in order to calculate and remove the effects of Earth's atmosphere; so they had to time their observation for when bright Io would be very close to Jupiter and the red spots would be visible (remember, Jupiter rotates, and fast, taking those red spots in and out of view). There's also some speculation on what could have made the white spot turn red. They mention two hypotheses: either the storm increased in strength so that it was able to dredge up red material from deep in the atmosphere, or the storm increased in strength so that it was able to dredge up some other kind of material that was then photochemically altered to a new, red material. Unfortunately they don't know what this red material is! Which makes it hard to get any further with hypothesizing. There's also this thought provoking story in a sidebar:

The formation of a new red spot on Jupiter, however, may also indicate a climate change on the planet. A recent study by Amy Simon-Miller (NASA-Goddard Space Flight Center) and Imke de Pater and Philip Marcus (University of California, Berkeley) shows that Red Spot Junior is gaining altitude. This indicates a temperature increase in that region. Marcus says that the relatively uniform temperature of Jupiter, where the temperatures at the poles are nearly the same as they are at the equator, is due to the chaotic mixing of heat and airflow from vortices in the planet's atmosphere. But Marcus predicted that the movement of heat from Jupiter's equator to its south pole would nearly shut off at 34˚ southern latitude. This is the same latitude where Red Spot Junior is located. This region may now be acting like a barrier that prevents the mixing of heat and airflow. If it is, Jupiter's equatorial regions will become warmer and its poles will become cooler. Consequently, the planet's average temperature at some latitudes could change by as much as 5.5 degrees Celsius (10 degrees Fahrenheit).

With the Great Red Spot being 350 years old (probably), we tend to think of Jupiter as being a very stable place -- it's a surprise to see someone saying that that may not be the case.

The image above is stunning but it's not what you would see if you looked through a telescope. Here's another great amateur astronomer view of what Jupiter now looks like to human eyes.

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Jupiter on July 15, 2006
Amateur astronomer D. Parker caught this view of Jupiter through a 16-inch Newtonian telescope on July 15, 2006. The small red spot that formed from the merger of several white spots has now traveled past the Great Red Spot. Click to see more of amateur Jupiter images from this event » Credit: D. Parker, Coral Gables, Florida