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March 3, 2006: Backyard astronomers, grab your telescopes.
Jupiter is growing a new red spot.
Christopher
Go of the Philippines photographed it on February 27th using
an 11-inch telescope and a CCD camera:
![see caption](images/redjr/go1_strip_lab.jpg)
Above:
Red spots on Jupiter, photographed by amateur astronomer Christopher
Go on Feb. 27, 2006. [Larger
image]
The
official name of this 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 centuries ago
may have created the original Great Red Spot, a storm twice
as wide as our planet and at least 300 years old.
At
first, Oval BA remained white—the same color as the storms
that combined to create it. But in recent months, things began
to change:
"The
oval was white in November 2005, it slowly turned brown in
December 2005, and red a few weeks ago," reports Go.
"Now it is the same color as the Great Red Spot!"
"Wow!"
says Dr. Glenn Orton, an astronomer at JPL who specializes
in studies of storms on Jupiter and other giant planets. "This
is convincing. We've been monitoring Jupiter for years to
see if Oval BA would turn red—and it finally seems to be happening."
(Red Jr? Orton prefers "the not-so-Great Red Spot.")
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," says Orton. The top of the
storm rises 8 km above surrounding clouds. "It takes
a powerful storm to lift material so high," he adds.
![ee caption](images/redjr/pia02823_med2.gif)
Above:
Hubble images detail the birth of oval BA in 1997-2000. [More]
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 Dr. John Rogers, author of the book "Jupiter: The
Giant Planet," which recounts telescopic observations
of Jupiter for the last 100+ years. "It will indeed be
interesting to see if Oval BA becomes permanently red."
See
for yourself: Jupiter is easy to find in the dawn sky. Step
outside before sunrise, look south and up: sky
map. Jupiter outshines everything around it. Small telescopes
have no trouble making out Jupiter's cloudbelts and its four
largest moons. Telescopes 10-inches or larger with CCD cameras
should be able to track Red Jr. with ease.
What's
next? Will Red Jr. remain red? Will it grow or subside? Stay
tuned for updates.
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Author: Dr. Tony
Phillips | Production Editor:
Dr. Tony Phillips | Credit: Science@NASA
|