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Jupiter has long been known for its Great Red Spot, but only recently have scientists learned more about how and how long ago it formed.

The huge vortex on the side of the largest planet in the solar system is a massive storm that was long thought to have been blowing for probably more than 300 years and to be larger than the entire Earth.

Now, according to a new study in the journal Geophysical Research Letters, astronomers have modeled how the storm formed and lasted so long and concluded that it may not be as old as first thought.

The Great Red Spot is a massive storm located in Jupiter’s southern hemisphere and was originally thought to have been first observed in the 17th century – notably by Giovanni Cassini, who named it the Persistent Spot (PS). The red spot, however, was not documented again until 1830, after which it was referred to as the Great Red Spot (GRS), with some suggesting that Cassini may instead have observed a different earlier large storm on the planet’s surface .

The researchers analyzed observations of the spot over several centuries, dating back to 1600, and used models to determine how it might have formed and persisted for so long, and whether the PS was indeed an early version of the GRS.

“From measurements of sizes and motions, we conclude that it is very unlikely that the present GRS is the PS observed by GD Cassini. PS probably disappeared sometime between the middle of the 18th and 19th centuries, in which case we can say that the longevity of the Red Spot now exceeds at least 190 years,” study co-author Agustin Sánchez-Lavega said in a statement , Professor of Physics at the University of the Basque Country (UPV/EHU).

In 1879, the spot was 24,233 miles in diameter and has slowly shrunk to its current size of 8,700 miles in diameter, gradually becoming more circular than oval in shape.

“Various instruments aboard the Juno mission in orbit around Jupiter showed that the GRS is shallow and thin compared to its horizontal size, as it is about 500 km long vertically,” Sanchez-Lavega said.

Above the GRS, winds are blowing at about 112 mph to the west, while below the storm they are blowing to the east at about 93 mph. This created a north-south shear, generating the giant storm vortex.

The researchers modeled the vortices of the wind blowing through Jupiter’s atmosphere and found that the GRS is unlikely to form from the merging of multiple vortices or through the eruption of a huge superstorm, such as is sometimes seen on Saturn, the second largest gas body in the solar system. system giant.

“We also think that if one of these unusual phenomena did occur, it or its atmospheric consequences must have been observed and reported by astronomers at the time,” Sánchez-Lavega said.

They found that if the winds are unstable in a certain way, they can create an elongated storm cell that traps them, generating a proto-GRS. This process has been observed before in other Jupiter vortices and would result in a contraction similar to what we have observed from the GRS over the years.

“In our simulations, the supercomputers allowed us to find that the elongated cells are stable when rotating around the GRS periphery at the speed of Jupiter’s winds, as would be expected when they form due to this instability,” co-author Enrique García-Melendo, researcher in physics at the Universitat Politècnica de Catalunya—BarcelonaTech (UPC), the statement said.

However, this explanation would require the vortex to spin at a very specific speed, as it would break up if too slow, or not remain stable if too fast.

The researchers hope to further study the GRS’s longevity and predict whether it will decay soon.

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