Jupiter's atmosphere has a zig-zag pattern of twelve jet streams which
make up its signature pastel-toned bands. Earth, by comparison, has
only two jet streams. The Great Red Spot is sandwiched between two of
these jets streams, forcing the winds that power those perimeter winds
to deflect around the spot.
Spacecraft observations of the way bands of high winds scream past
the Red Spot show how the spot -- inaccurately described as a storm --
is actually far calmer at its center than other parts of the Jovian
atmosphere. The winds at the center are just 9 or 10 miles per hour,
whereas around the perimeter they exceed 200 miles per hour.
A new, third red spot, which is a fraction of the size of the two
other red spots, has been observed on Jupiter to the west of the Great
Red Spot in the same latitude band of clouds. The visible-light images
were taken on May 9 and 10 with Hubble's Wide Field and Planetary
The new red spot morphed from a white oval-shaped storm to a red
color indicating its swirling storm clouds are rising to heights like
the clouds of the Great Red Spot. Astronomers surmise that one possible
explanation is that the red storm is so powerful it dredges material
from deep beneath Jupiter's cloud tops and lifts it to higher altitudes
where solar ultraviolet radiation -- via some unknown chemical reaction
-- produces the familiar brick color.
Because all three oval storms are bright in near-infrared light,
they must be towering above the methane in Jupiter's atmosphere, which
absorbs the Sun's infrared light and so looks dark in infrared images.
Turbulence and storms first observed on Jupiter more than two years
ago are still raging, as revealed in the latest pictures. The Hubble
and Keck images also reveal the change from a rather bland, quiescent
band surrounding the Great Red Spot just over a year ago to one of
incredible turbulence on both sides of the spot.
The Great Red Spot has persisted for as long as 200 to 350 years,
based on early telescopic observations. If the new red spot and the
Great Red Spot continue on their courses, they will encounter each
other in August, and the small oval will either be absorbed or repelled
from the Great Red Spot. Red Spot Jr. which lies between the two other
spots, and is at a lower latitude, will pass the Great Red Spot in June.
Posted by Casey Kazan. Image: Jupiter and Giant Red Spot seen from
its moon, Io. Vistapro Landscape Imagery Rendered by Jeff Bryant.
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