by Dr. Tony Phillips

from Science@NASA Website



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:




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 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.

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.


Storms Collide on Jupiter

24 October 2000

from Science@NASA Website


NASA's Hubble Space Telescope

has captured dramatic images of two swirling storms on Jupiter

as they collided to form a truly titanic tempest.




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 Propulsion Laboratory.

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.

Jupiter's White Ovals/True and False Color
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011

July 28, 1997

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 counterclockwise sense.

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 Jupiter.

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 Galileo spacecraft.

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 (Caltech).

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 clouds.

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 smaller.




Hubble images detail the birth of oval BA in 1997-2000

These four Hubble Space Telescope images show steps

in the consolidation of three "white oval" storms into one over a three-year span of time.


PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011

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 right.

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 2000.

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 last December.

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 Space Agency.




Jupiter’s “White Ovals” Take Scientists by Storm

by Douglas Isbell and Jane Platt
Headquarters, Washington, DC October 14, 1998 (Phone: 202/358-1753)
Jet Propulsion Laboratory, Pasadena, CA (Phone: 818/354-5011)
RELEASE: 98-188

from AstronomyPictureoftheDay Website

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 itself.

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 storm systems.”

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 said.

This might mean the storm is in a transition stage, undergoing a rebirth after the merging of the two storms.

“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.

Related images and information on the Galileo mission are available on the Internet at the Galileo website: