Welcome to Jupiter, home of the solar system's largest
hurricane. (Photo courtesy NASA/JPL/Space Science
Institute)
If the perils of coastal storms seem bad, let's be thankful we
aren't living on Jupiter. The giant eye-shaped swirl shown in
the photo above is a hurricane that has been raging for over
300 years. The Great Red Spot, as it's casually known, is the
largest storm in the solar system, with a diameter of 15,400
miles (large enough to fit two Earths inside with room to
spare) and winds estimated at 270 mph. By comparison, the most
intense storms on Earth include Hurricane Camille, which
created a 25-foot storm surge that landed in Mississippi in
1969, and Hurricane Allen, which swept over Jamaica in 1980.
Both storms had winds estimated at 190 mph, though no one's
completely sure, since at those speeds all the weather
instruments were completely destroyed.
All that can be seen on Jupiter are clouds. Unlike Earth, where
clouds consist of water vapor alone, Jupiter's clouds are made
of ammonia, hydrogen sulfide, and water. According to NASA
observers, the brown and orange colors may be due to trace
chemicals dredged up from deeper levels of the atmosphere,
while the bluish bands are areas of reduced cloud cover where
one can see deeper into the atmosphere. As clouds are sheared
apart by the intense jet streams that run parallel to the
planet's equator, streaks form in the atmosphere. The prominent
dark band in the northern half of the planet is Jupiter's
fastest jet stream, with eastward winds of about 300 mph.
The Great Red Spot presumably persists on Jupiter because there
are no land masses to disrupt the storm. On Earth, the
difference in temperature between the warm ocean waters and
cooler air above keep hurricanes alive. As a weather
disturbance begins mixing the two temperatures, water vapor
from the warm ocean surface evaporates, forming towering clouds
that surround the eye of the storm. As water vapor rises and
cools, it condenses, which releases latent heat. The released
heat warms the surrounding air, making it lighter and promoting
more clouds, thus creating the engine that drives the hurricane
onwards until it moves over a mass of cold water or comes
ashore, effectively cutting off its energy supply. —
Clayton DeKorne