Reported November 2008

About the Little Red Spot: The Little Red Spot on Jupiter is an anti-cyclonic storm formed by the merger of three separate storms observed since the 1930s. In 1998, two of the storms came together. They were joined in 2000 by a third storm to form a storm roughly the size of the planet Earth. Using data from recent telescope and spacecraft observations, scientists determined that the storm has some of the highest wind speeds ever detected on any planet. In 2005, it started turning red for unknown reasons, and now it looks similar to its larger, more famous neighbor, the Great Red Spot. The peak wind speed for the Little Red Spot is over 384 miles per hour.

What is an Anticyclone?: Unlike hurricanes, which rotate around a center of low pressure, anticyclones rotate around centers of high pressure. On Earth, that means air at lower elevations is forced away from the center, creating an opening that pulls cold air down from above. That leads to low humidity and few clouds. On Earth, anticyclones are often predictors of fair weather, though special conditions can create anticyclonic tornadoes. There are examples of anti-cyclonic storms on other planets like Jupiter, Saturn and Neptune.

The American Astronomical Society contributed to the information contained in the TV portion of this report.

If you would like more information, please contact:

Michael Buckley
Office of Communications and Public Affairs
Johns Hopkins University Applied Physics Laboratory
Laurel, MD
(240) 228-7536
Michael.Buckley@jhuapl.edu

Steve Maran
American Astronomical Society
Washington, DC 20009-1231
(202) 328-2010
steve.maran@aas.org