Jupiter is known for its Great Red Spot, a storm twice the Earth's diameter that rages on the surface of the gas planet. Now, scientists report that they have found another great spot on the gas giant which was nearly as large as the red one.
Bigger Than Earth
The Great Cold Spot was discovered using data from the Very Large Telescope in Chile and it shares a number of similarities with Jupiter's famed red spot.
Just like its cousin estimated to span twice the diameter of Earth, the Great Cold Spot is also bigger than our home planet spanning nearly 15,000 miles in longitude and 7,500 miles in latitude. Images taken by the Hubble Space Telescope, however, showed that the Great Red Spot is continuously shrinking. Researchers said that the spot is now only about 10,250 miles across, which is less than half of its historical size.
Technically A Weather
The cold region, which is extremely cold when compared with the rest of the Jovian atmosphere, is not also a spot per se. Just like the Great Red Spot, the Great Cold Spot is a weather.
The Great Red Spot is believed to be the product of a massive storm raging in the violent and gaseous atmosphere of the Solar System's largest planet. The Great Cold Spot also appears to be a weather system. Researchers think that the spot is formed as a byproduct of the gas giant's spectacular auroras.
The gas giant's aurora drives energy into the atmosphere in the form of heat that flows around the planet creating a region of cooling in a layer of the atmosphere. Researchers think that sustained cooling likely drives vortices comparable to the Great Red Spot. Based on how the cool spot always reforms, researchers think it could be as old as the auroras in Jupiter themselves, which are up to thousands of years old.
"This is the first time any weather feature in Jupiter's upper atmosphere has been observed away from the planet's bright aurorae," said planetary astronomer Tom Stallard, from the University of Leicester in the United Kingdom.
Jupiter's Great Cold Spot More Volatile Than Great Red Spot
The cold spot is far more volatile when compared with the Great Red Spot. It was observed to disappear from time to time but always reforms as shown by data spanning over 15 years. It also dramatically shifts in size and shape over short periods of time.
Researchers have also observed that in the last few years, the Great Red Spot also shifted shape from oval to circle. Astronomers, however, more notably recorded declining measurements of the mammoth storm.
"This region, similar in size to the Great Red Spot, appears to be a large vortex located at very high altitudes, but unlike weather systems lower in the atmosphere, it appears to be directly related to the planet's aurora," Stallard and colleagues wrote in their report describing the Great Cold Spot. The study was published in Geophysical Research Letters on April 11.