NASA’s Hubble Space Telescope (HST) has detected a new storm on Jupiter (approximately 142,000 km across), the largest planet. The storm appears as a red spot near the planet’s larger famous red storms, the Great Red Spot (GRS) and Red Spot Jr., which are also giant storms.

The new red spot was previously a white oval-shaped storm, but its color turned red. This change in color indicates the storm’s swirling clouds are rising to altitudes similar to those of the clouds of the GRS. Probably, the red storm is so powerful it dredges material from deeper layers of Jupiter's atmosphere and lifts it to higher elevations where solar ultraviolet radiation produces the distinctive brick color.

Detailed analysis of the visual-light images taken by HST's WFPC 2 instrument on 9 May and 10 May, and infrared images acquired by the giant Earth-based Keck telescope on 11 May, is revealing the relative altitudes of the cloud tops of the three red storms. As the three red spots are bright in infrared emission, they must be located above the methane in Jupiter's atmosphere, which absorbs the Sun's infrared emission, and therefore appears dark in infrared images.

For over two years, astronomers have been monitoring turbulence and storms on Jupiter. The Hubble and Keck images also reveal a drastic change in the cloud band surrounding the GRS. Just over a year ago the band was quite and bland; now it shows incredible turbulence on both sides of the GRS.

The GRS has persisted for at least 200 years, and some early telescopic observations indicate it was noticed by 17th century observers. The GRS is about 12,000 by 25,000 km in area, or about twice the size of Earth. Red Spot Jr. appeared in spring of 2006.
If the new red spot and the GRS continue on their tracks, they will encounter each other in August 2008, and the smaller storm will either be absorbed or repelled from the GRS. Red Spot Jr., which lies at a lower latitude between the two other spots, will pass the GRS in June 2008.

The Hubble and Keck images may bolster the idea that Jupiter is in the midst of global climate change, as first proposed in 2004 by Phil Marcus, a professor of mechanical engineering at the University of California, Berkeley. The planet's temperatures may be changing by 15 to 20 degrees Fahrenheit. The equatorial region of the giant planet is getting warmer, but near the South Pole, it is getting cooler. He predicted that major changes would spawn new vortices.

Further Reading

New Red Spot Appears on Jupiter
http://hubblesite.org/newscenter/archive/releases/2008/23/image/a/
Hubble Catches Jupiter Changing Its Stripes
http://hubblesite.org/newscenter/archive/releases/2007/25/
Hubble Snaps Baby Pictures of Jupiter's "Red Spot Jr."

Aymen Mohamed Ibrahem  
Senior Astronomy Specialist