Jupiter is known as a gas giant and does not have a surface as such. What we see through our telescopes are features at the top of the atmosphere - Jupiters cloud tops. However, the term 'surface features' although not technically correct is sometimes used in the popular media.
This brief movie shows counterclockwise atmospheric motion around
Jupiter's Great Red Spot. The clip was made from blue-filter
images taken with the narrow-angle camera on NASA's Cassini
spacecraft during seven separate rotations of Jupiter between
Oct. 1 and Oct. 5, 2000.
The clip also shows the eastward and westward motion of the zonal
jets, seen as the horizontal stripes flowing in opposite
directions. The zonal jets circle the planet. As far as can be
determined from both Earth-based and spacecraft measurements, the
positions and speeds of the jets have not changed for 100 years.
Since Jupiter is a fluid planet without a solid boundary, the jet
speeds are measured relative to Jupiter's magnetic field, which
rotates, wobbling like a top because of its tilt, every 9 hours
55.5 minutes. The movie shows motions in the magnetic reference
frame, so winds to the west correspond to features that are
rotating a little slower than the magnetic field, and eastward
winds correspond to features rotating a little faster.
Because the Red Spot is in the southern hemisphere, the direction
of motion indicates it is a high-pressure center. Small bright
clouds appear suddenly to the west of the Great Red Spot.
Scientists suspect these small white features are lightning
storms. The storms eventually merge with the Red Spot and
surrounding jets, and may be the main energy source for the
large-scale features.
The smallest features in the movie are about 500 kilometers
(about 300 miles) across. The spacing of the movie frames in time
is not uniform; some consecutive images are separated by two
Jupiter rotations, and some by one. The images have been re-
projected using a simple cylindrical map projection. They show an
area from 50 degrees north of Jupiter's equator to 50 degrees
south, extending 100 degrees east-west, about one quarter of
Jupiter's circumference.
Credit: NASA/JPL/University of Arizona
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Galileo was the first person to observe this feature. The Great Red spot is like a giant storm that has been ragging for hundreds of years.
The clip also shows the eastward and westward motion of the zonal
jets, seen as the horizontal stripes flowing in opposite
directions. The zonal jets circle the planet. As far as can be
determined from both Earth-based and spacecraft measurements, the
positions and speeds of the jets have not changed for 100 years.
Since Jupiter is a fluid planet without a solid boundary, the jet
speeds are measured relative to Jupiter's magnetic field, which
rotates, wobbling like a top because of its tilt, every 9 hours
55.5 minutes. The movie shows motions in the magnetic reference
frame, so winds to the west correspond to features that are
rotating a little slower than the magnetic field, and eastward
winds correspond to features rotating a little faster.
