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
Red spots on Jupiter,
photographed by amateur astronomer Christopher Go on Feb. 27, 2006.
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
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
"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.")
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.
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
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.
has captured dramatic images of two
swirling storms on Jupiter
as they collided to form a truly titanic
tempest. Listen to this story
October 24, 2000
-- For the first time, scientists have
been able to watch two of Jupiter's giant storms, each about half
the size of Earth, colliding and merging to form an even bigger
tempest. A similar merger centuries ago may have created Jupiter's
famous Great Red Spot, a storm that is twice as wide as our
planet and at least 300 years old.
"Usually when we've seen two of [the
white ovals] approaching each other, they bounce back [apart],"
said Glenn Orton, senior research scientist at NASA's Jet
But this time the storms came together
in a complicated dance that scientists recorded using the Hubble
Space Telescope and ground-based observatories.
For sixty long years Jupiter's striking
white ovals, pictured here in an image from NASA's Galileo
spacecraft, existed as distinct storms.
Since 1998 they've merged to form a
titanic tempest second in size only to the Great Red Spot itself.
Recent observations from the Hubble
Space telescope captured for the first time two of the ovals in the
act of coalescing.
Oval cloud systems of this type are often associated
with chaotic cyclonic systems such as the
balloon-shaped vortex seen here between the
well-formed ovals. This system is centered near 30
degrees south latitude relative to the center of the
planet and 100 degrees west longitude, and rotates
in a clockwise direction about its center. The oval
shaped vortices in the upper half of the mosaic are
two of the three long-lived white ovals that formed
to the south of the Great Red Spot in the 1930's
and, like the Great Red Spot, rotate in a
The east-to-west dimension of the left-most white
oval is 9,000 kilometers (5,592 miles) across. For
comparison, the diameter of Earth is 12,756
kilometers, or 7,928 miles. The white ovals drift in
longitude relative to one another and are presently
restricting the cyclonic structure. To the south,
the smaller oval and its accompanying cyclonic
system are moving eastward at about 0.4 degrees per
day relative to the larger ovals. The interaction
between these two cyclonic storm systems is
producing high, thick cumulus-like clouds in the
southern part of the more northerly trapped system.
The top mosaic combines the violet (410 nanometers)
and near infrared continuum (756 nanometers) filter
images to create a mosaic similar to how Jupiter
would appear to human eyes. Differences in
coloration are due to the composition and abundance
of trace chemicals in Jupiter's atmosphere.
The lower mosaic uses the Galileo imaging camera's
three near-infrared wavelengths (756 nanometers, 727
nanometers, and 889 nanometers displayed in red,
green, and blue) to show variations in cloud height
and thickness. Light blue clouds are high and thin,
reddish clouds are deep, and white clouds are high
and thick. The clouds and haze over the white ovals
are high, extending into Jupiter's stratosphere.
There is a lack of high haze over the cyclonic
feature. Dark purple most likely represents a high
haze overlying a clear deep atmosphere. Galileo is
the first spacecraft to distinguish cloud layers on
North is at the top of these mosaics. The smallest
resolved features are tens of kilometers in size.
These images were taken on February 19, 1997, at a
range of 1.1 million kilometers (683,507 miles) by
the solid state imaging (CCD) system aboard NASA's
The Jet Propulsion Laboratory, Pasadena, CA manages
the Galileo mission for NASA's Office of Space
Science, Washington, DC. JPL is an operating
division of California Institute of Technology
Seeing the collision of two such storms
will help scientists understand more about the dynamics of Jupiter's
atmosphere, says Agustin Sanchez-Lavega, an astronomer at
Universidad del Pais Vasco, who reported the team's observations
yesterday at a meeting of the American Astronomical Society in
Pasadena. One question has been how deeply the roots of a storm at
Jupiter's cloud tops extend into lower layers. In this year's
merger, the upper layer seemed to move differently than underlying
Three white oval storms, in a band of Jupiter's atmosphere farther
south than the Great Red Spot, became active about 60 years ago. In
the following decades until 1998, they sometimes approached each
other but never collided. In early 1998, two of the ovals were
approaching each other as Jupiter went out of sight from Earth,
behind the Sun.
When the planet came back into view,
the two had become one. (click below image)
"We weren't able to see how they
came together that time," Orton said.
Last year, the oval resulting from the
1998 combination approached the remaining one of the original three
ovals. Each was a swirling high-pressure vortex, upwelling at the
center and spinning winds counterclockwise to about 470 kilometers
per hour. One was about 9,000 kilometers across, the other slightly
Hubble images detail
the birth of oval BA in 1997-2000
These four Hubble Space Telescope images
in the consolidation of three "white
oval" storms into one over a three-year span of time.
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IMAGE CAPTION PIA-02823
Oval Storms Merging on Jupiter
October 23, 2000
These four images of clouds in a portion of Jupiter’s
southern hemisphere show steps in the consolidation of
three “white oval” storms into one over a three-year
span of time. They were obtained on four dates, from
Sept. 18, 1997, to Sept. 2, 2000, by NASA’s Hubble Space
Telescope. The widths of the white ovals range from
about 8,000 kilometers to 12,000 kilometers (about 5,000
miles to 7,500 miles). North is up and east is to the
The top image shows three white oval storms, which had
coexisted for about 60 years. They were nicknamed FA, DE
and BC, in order from west to east. By mid-1998, as
shown in the second image, the two easternmost storms
had merged into one, called BE. By October 1999, as
shown in the third image, the merged oval and the last
of the original three were approaching each other, but
they were separated by a dark storm, called o1, between
them. The two white oval storms later merged into a
single storm, as shown in the final image from September
The Hubble Space Telescope is a facility of NASA and the
European Space Agency. It is operated by the Space
Telescope Science Institute, Baltimore, Md., which is
managed for NASA by the Association of Universities for
Research in Astronomy in Honolulu.
A third, darker oval, swirling clockwise
instead of counterclockwise, formed temporarily between the two
white ovals. That type of interceding system may be what usually
keeps white ovals from colliding, the team proposed. But in this
case, the middle storm appears to have been pushed even farther
south and torn apart as all three passed near the Great Red Spot
The disappearance of the opposite-swirling storm cleared the way for
the two white ovals to meet.
Their collision dance began in March and lasted about three weeks.
At the cloud tops, the storms circled around each other
counterclockwise, then consolidated into a single oval about
one-third wider than either had been beforehand. The ovals' approach
and merger was viewed in various wavelengths, showing events at
different depths, with a planetary telescope at Pic-du-Midi in
France, NASA's Infrared Telescope Facility in Hawaii, and the
orbiting Hubble Space Telescope, a facility of NASA and the European
As powerful hurricanes pummel coastal areas on Earth, NASA space
scientists are studying similar giant, swirling storms on distant
Jupiter that have combined to spawn a storm as large as Earth
Three separate cold storms, called “white ovals” because of their
color and egg shapes, have been observed in one band around
Jupiter’s mid-section for half a century. Two of the storms recently
merged to form a larger white oval, according to scientists studying
data from NASA’s Galileo spacecraft, the Hubble Space Telescope, and
the Agency’s Infrared Telescope Facility atop Mauna Kea, HI.
“The newly merged white oval is the
strongest storm in our Solar System, with the exception of
Jupiter’s 200-year-old ‘Great Red Spot’ storm,” according to Dr.
Glenn Orton, senior research scientist at NASA’s Jet Propulsion
Laboratory (JPL), Pasadena, CA. “This may be the first time
humans have ever observed such a large interaction between two
Each of the white ovals that merged were
about two-thirds the diameter of the Earth before the merger, when
they combined to form a feature as large as the Earth’s disc.
Although scientists have observed the end result of the merger of
the two white ovals, the actual “collision” took place under cover
of darkness while Jupiter was turned away from view.
This new, powerful white oval has a
mysterious trait, according to Orton.
“We can see it, along with the other
white ovals, at visible light and some infrared wavelengths, but
we cannot see the new white oval at certain infrared wavelengths
that peer underneath the storm’s upper cloud layers,” Orton
This might mean the storm is in a
transition stage, undergoing a rebirth after the merging of the two
“With mature white ovals, we can see
the upwelling of winds in the center, which in turn leads to
downwelling around it,” Orton said.
The new white oval has a very cold
center (about -251 Fahrenheit or -157 Celsius) that is about one
degree colder than its surroundings.
“Because of this, the oval may have
generated a thick cloud system which obscures the downwelling,”
Orton said, which could explain the new oval’s
“disappearing act” at some wavelengths.
Adding to the mystery is the fact that a
nearby storm rotating in the opposite direction to the new white
oval used to be warmer than its surrounding.
“This probably means that the
feature contained mostly downwelling winds,” said Orton.
However, Galileo’s photopolarimeter
radiometer instrument showed this feature had cooled down to
temperatures that were about the same as its surroundings.
Orton suspects that this storm somehow lost power and is no longer
spinning as fast or downwelling as strongly as a year ago. This
storm was once positioned between the two smaller white ovals that
merged, and Orton theorized that when this storm system lost
power, it removed the buffering mechanism that kept the two original
white ovals apart.
Orton and his colleague, Dr. Brendan Fisher, a Caltech
postdoctoral fellow at JPL, based their conclusions about the
temperatures using data gathered by Galileo on July 20, 1998, during
the spacecraft’s 17th orbit of Jupiter and its moons. Although much
data from the flyby of Europa in that time period was lost because
of a problem with the spacecraft’s gyroscope, Galileo’s
photopolarimeter radiometer gathered the new data on the white ovals
before the anomaly occurred.
The photopolarimeter radiometer measures temperature profiles and
energy balance of Jupiter’s atmosphere, helping scientists study the
huge planet’s cloud characteristics and composition. Scientists
believe that the bright, visible clouds of the white ovals are
composed of ammonia.
Galileo has been in orbit around Jupiter and its moons for 2½
years, and is currently in the midst of a two-year mission
extension, known as the Galileo Europa Mission. JPL manages
the Galileo mission for NASA’s Office of Space Science, Washington,
DC. JPL is a division of Caltech, Pasadena, CA.