Great Red Spot of Jupiter
most well-known feature of our solar system's biggest planet,
what is this gigantic, crimson oval and is it about to disappear?
caught in a summer rainstorm for an hour at a picnic and forced
to huddle under one of those little pavilions, those sixty minutes
seem to last forever. But what if the storm lasted all day? Or
even a week? Or a year? What if the storm lasted for centuries?
that might be the case if you were having your picnic on the planet
Jupiter. A large, red oval that can be seen in the southern hemisphere
is evidence of a gigantic storm taking place there with wind speeds
in the hundreds of miles per hour. A storm that has lasted for
Southern Hemisphere of the Planet Jupiter.
Not known for sure. May have been observed by Robert Hook
or Gian Domenico Cassini in the late 17th century.
Between 15,000 and 25,000 miles (24-40,000 km) in length
and between 7,500 and 8,700 miles (12-14,000km) in width.
Speeds: 270 miles per hour (432 km/h) at the outer edges.
Unknown, but has persisted for somewhere between two and
three and a half centuries.
It is an anti-cyclonic storm, moving in a counterclockwise
Appears to be shrinking and may someday disappear.
for sure that the spot has existed much as we see today since
1878 when American astronomer Carr Walter Pritchett observed it
using the Pritchett Institute's 12-inch refractor telescope. There
are indications, however, that its discovery may have proceeded
Pritchett's observations by at least a century. In 1831 German
astronomer Samuel Heinrich Schwabe made a drawing that seems to
show if not the spot itself, then the gap around it. Even further
back at the end of the 17th century, Gian Domenico Cassini, the
Italian astronomer, noted a "permanent spot" on the planet that
might be an early observation of the massive storm. English astronomer
Robert Hook also mentioned a spot on Jupiter he saw in 1664, but
some scholars believe he was actually observing a shadow of a
moon in the northern hemisphere.
however, never mentions the spot as being red. This maybe because
the low power of his telescope may have not permitted him to distinguish
the color. It's also a possibility that the spot may have been
white at the time (like most of the smaller storms on Jupiter
are). There is also a chance that he could have been looking at
another storm completely that disappeared in the 18th century
and returned later as the disturbance we know today.
spot is at least a century and a half old and quite possibly more
than double that. We also know that as long as it has been observed,
it has stayed very close to the same latitude (22° south of Jupiter's
equator) but has changed its position longitudinally (east to
west). The spot stays at the same latitude because of the planet's
winds. There are jet streams moving past it toward the north and
south. The southern stream rushes eastward and the northern stream
moves to the west. The storm seems to be trapped between the two.
red spot's size can be compared to Earth in this composite
how much movement the storm has made longitudinally is hard to
say. Because the planet is almost entirely gas, it does not rotate
at the same speed at every latitude. Even so, scientists believe
that the spot has 'lapped' the planet at least 10 times since
the early 19th century.
Size and Color
itself is an anti-cyclonic storm. This means that since it's in
the southern hemisphere, it moves in a counterclockwise rotation
around a high pressure system. On Earth such storms are associated
with cold weather. This also seems to be the case on Jupiter as
infrared measurements have shown that the Great Red Spot is colder
and higher in altitude (about 5 miles or 8km) than the other clouds
on the planet.
is immense in size and at one point could have contained three
objects the size of planet Earth. The size has changed over time
with a length (east and west) of between 15,000 and 25,000 miles
(24-40,000 km) and a width of between 7,500 and 8,700 miles (12-14,000km).
The storm, because of its large size, takes 6 Earth days to make
one rotation, though the winds at the outer edges of the storm
are moving at a blistering 270 miles per hour (432 km/h). The
wind speeds toward the center of the storm are lower and in the
very center the winds actually reverse and turn slowly clockwise.
the Great Red Spot red? Scientists are not really sure, but it
may be because the gases in it contain materials like complex
organic molecules, or red phosphorus, or some other unknown sulfur
compound. Why these compounds show up so much in the spot's clouds
are unknown, but there is some speculation that the storm is large
enough to drag materials up from the lower levels of the planet's
atmosphere that are not usually exposed to the sun.
color isn't consistent either. It varies greatly in hue, sometimes
appearing as almost a brick red. At other times it can be pale
salmon, or almost white.
Red Spot is located in Jupiter's southern hemisphere.
the spot managed to stay stable for hundreds of years when even
the largest storms on Earth seem to die out after only a week
or two? One of the reasons maybe because if Jupiter has a solid
core (and some scientists argue it does not) it is deep down under
thousands and thousands of miles of gas. Most big storms on Earth
peter out when they drift over land. Since Jupiter (for all practical
purposes) has no land, storms may stay stable for an extended
length of time.
scientists running computer simulations of the storm have felt
a lifetime of several centuries still seems too long . In 2013,
however, researchers Pedram Hassanzadeh and Philip Marcus developed
a new computer model of the spot's motion. The model takes into
consideration not just the horizontal flow of the winds, but also
the vertical ones. Hassanzadeh and Marcus believe that these vertical
flows move hot and cold gases in and out of the system, restoring
part of the storm's energy. Their model predicts that the Great
Red Spot might survive as long as 800 years.
are some indications in recent years that the great storm may
be subsiding. It is half the length it was a century ago and has
lost 15 percent of its diameter just between 1996 and 2006. It's
hard to tell, however, if this is just part of a regular fluctuation
of the spot, or a definitive trend. We do know that someday the
great storm will come to an end. "It's just a storm that," says
Glenn Orton, a senior research scientist at NASA'S Jet Propulsion
Laboratory, "like many things, has a natural growth and disintegration
animation shows the cloud movements across Jupiter's surface.
Notice the jet streams to the north and south of the red
spot moving in different directions and trapping it between
2014 Lee Krystek. All Rights Reserved.