Jupiter’s famous Great Red Spot appears younger than previously thought

Although this massive storm, at 190 years old, is still the longest-lived tornado in the solar system, it does not look the same as the one observed by astronomer Giovanni Cassini in 1665.

The Great Red Spot on Jupiter is the largest known atmospheric vortex in our solar system. However, his age has long been a topic of debate. Researchers also still don’t know exactly how the massive storm originated. a New study Now it sheds more light on the issue – and even disproves a long-standing theory.

More about Jupiter’s Great Red Spot
Jupiter is known for its colorful bands and huge swirling storms. The most famous storm – and perhaps the most famous in the entire solar system – is the Great Red Spot; A massive anticyclone has been raging over the gas giant for many years. The Great Red Spot is a massive atmospheric vortex, roughly the size of the Earth. On its outer edges, winds blow at speeds of up to 450 kilometers per hour. The red color results from chemical reactions in the atmosphere, providing a striking contrast with the gas giant’s pale clouds. The Great Red Spot has fascinated generations of scientists. This has to do with its size, but also with the fact that the storm is visible even with small telescopes.

When did astronomers first see the Great Red Spot appear in the night sky? So there’s some disagreement about that. In 1665, the Italian-French astronomer and engineer Giovanni Cassini discovered a dark oval at the same latitude as the present-day Great Red Spot, which he called the Permanent Spot. But it turns out that the storm is not so “permanent”; In 1713 she suddenly disappeared. It was not until 1831 after which scholars again saw a distinct oval structure at the same location. Sporadic historical observations of Jupiter’s spots have led scientists into a long debate over whether the Great Red Spot that exists today is the same one observed by a scientist in the 17th century.

Stady
To gain more insight into the evolution of spot size, structure and location over time, the researchers analyzed historical observations from the 17th century. “It has been very inspiring and stimulating to study the observations and drawings made by the pioneering astronomer Cassini,” said researcher Agustín Sanchez La Vega.

The study leads to a surprising discovery. “Based on our measurements of the size and movements of the Great Red Spot, we concluded that this spot was unlikely to be the same ‘permanent spot’ observed by Cassini,” says Sánchez La Vega.

190 years
In short, the Great Red Spot on Jupiter is not the same storm that Cassini observed in the 17th century. Therefore the first mentioned storm is much smaller than previously thought. “The Permanent Spot ‘probably disappeared sometime between the mid-18th and 19th centuries,'” Sanchez Lavega noted. Despite this younger age, the Great Red Spot remains the longest-lived vortex in the solar system, at about 190 years old.

characteristics
The researchers came up with more interesting facts in their study. For example, they write, the Great Red Spot has shrunk since 1879 from a long axis of 39,000 km to a long axis of 14,000 km today. The storm has also become somewhat rounder in the meantime.

Origin
But the question now remains: How did the Great Red Spot appear? To find out, the researchers ran numerical simulations on supercomputers. They used two models to study the behavior of eddies in Jupiter’s atmosphere. This has led to many interesting theories. For example, the spot could have been created by a massive superstorm, such as the one that sometimes occurs on Jupiter’s neighboring planet Saturn. The storm may also have formed from the merger of several smaller tornadoes, caused by strong wind currents running side by side but changing direction with latitude. Although an anticyclone forms in both cases, it differs in shape and characteristics from the current Great Red Spot, prompting researchers to write off these theories. Another possible reason is unstable winds. This creates an elongated air cell, with a shape similar to that of the great red spot. This may have led to the formation of the so-called “proto-Great Red Spot” that contracted over time, eventually giving rise to the compact, rapidly rotating Great Red Spot observed by astronomers in the late 19th century.

Although the study clarified some things, the researchers have not given up on the topic yet. For example, in future research they plan to study the contraction of the anticyclone over time, to elucidate the physical mechanisms behind its relative stability. In addition, they want to know whether the storm will eventually dissipate once it reaches a certain size — similar to what may have happened with Cassini’s permanent spot — or whether it will stabilize at a certain size and persist for many years.