Backyard astronomers, grab
your telescopes. Jupiter is growing a new red spot.
The official name of the
new storm is "Oval BA," but "Red Jr." might be better. It's
about half the size of the famous Great Red Spot and almost exactly the same
color.
Oval BA first appeared in
the year 2000 when three smaller spots collided and merged. Using Hubble and
other telescopes, astronomers watched with great interest. A similar merger that
happened centuries ago may have created the original Great Red Spot, a storm
twice as wide as our planet and at least 300 years old.
Oval BA has been changing
colors in recent months. It was white in November 2005, slowly turned brown in
December and then red a few weeks ago.
Why red?
Curiously, no one knows
precisely why the Great Red Spot itself is red. A favorite idea is that the
storm dredges material from deep beneath Jupiter's cloudtops and lifts it to
high altitudes where solar ultraviolet radiation--via some unknown chemical
reaction--produces the familiar brick color.
"The Great Red Spot is
the most powerful storm on Jupiter, indeed, in the whole solar system," said
Glenn Orton, an astronomer at JPL who specializes in studies of storms on
Jupiter and other giant planets.
"The top of the storm rises
8 km above surrounding clouds. It takes a powerful storm to lift material so
high," Orton said.
Oval BA may have
strengthened enough to do the same. Like the Great Red Spot, Red Jr. may be
lifting material above the clouds where solar ultraviolet rays turn "chromophores"
(color-changing compounds) red. If so, the deepening red is a sign that the
storm is intensifying.
"Some of Jupiter's
white ovals have appeared slightly reddish before, for example in late 1999,
but not often and not for long," says John Rogers, author of the book "Jupiter:
The Giant Planet," which recounts telescopic observations of Jupiter over
the last 100 years.
"It will indeed be
interesting to see if Oval BA becomes permanently red," Rogers said.
Jupiter's Red Spot:
Images of the Storm
Dark Spot on Jupiter Bigger than Famed Great Red Spot
Mystery Spot on Jupiter Baffles Astronomers
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