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Jupiter’s iconic Great Red Spot is a massive storm that has been swirling through the atmosphere of the solar system’s largest planet for years.
But astronomers have debated the true age of the vortex, as well as when and how it formed. Some experts believed it was centuries old and first observed by Italian astronomer Giovanni Domenico Cassini in the 17th century, while others thought the storm was more recent.
Now, new research suggests that the Great Red Spot formed about 190 years ago, meaning Cassini observed something else on Jupiter in 1665. And although it is younger than Unexpectedly, the storm remains both the largest and longest known vortex across our planet. solar system, according to researchers.
A study detailing the results appeared June 16 in the journal Geophysical Research Letters.
Jupiter’s striking appearance features stripes and spots composed of cloud bands surrounding the planet and cyclonic storms. Its colors come from the composition of different atmospheric layers, individually made up of ammonia, water ice, sulfur and phosphorus, according to NASA. Fast-moving jet streams sculpt and stretch the clouds into long strips.
Cyclonic storms on Jupiter can last for years because the gas planet has no solid surface, which can slow down storms.
The Great Red Spot is a massive vortex in Jupiter’s atmosphere that is about 16,350 kilometers wide, which is similar to the diameter of Earth, according to NASA. The storm rises to a height of more than 200 miles (322 kilometers).
Howling winds are blowing at 280 miles per hour (450 kilometers per hour) along the storm’s boundaries. And its characteristic red hue comes from atmospheric chemical reactions.
This iconic feature is visible even through small telescopes.
And it looked like a dark oval at the same latitude that Cassini first spotted while looking through his telescope in the mid-1600s. He called the feature he observed the “permanent point.” , and Cassini and other astronomers observed it until 1713, when they lost sight of the storm.
Then, in 1831, astronomers spotted a large oval-shaped storm at the same latitude on Jupiter, which persisted and is still observed today. But astronomers have long wondered whether it was possible that the storms were the same phenomenon, or two different vortices appearing in the same place more than a century apart.
A team of researchers aiming to solve the puzzle have gathered a wealth of data, analyzing historical drawings and images that depict the structure, location and size of the place over time. The data was used to create numerical models recreating the potential longevity of the storm.
Ann Ronan Pictures/Print Collector/Getty Images
Astronomer Giovanni Domenico Cassini first observed what he called the “permanent spot” on Jupiter in 1665. New research suggests the Great Red Spot formed about 190 years ago, which means that Cassini observed something else on the planet in the 17th century.
“From measurements of sizes and movements, we deduced that it is very unlikely that the current Great Red Spot is the ‘Permanent Spot’ observed by Cassini,” said the study’s lead author, Agustín Sánchez-Lavega. , professor of applied physics at the University. of the Basque Country in Bilbao, Spain, in a press release. “The ‘Permanent Stain’ probably disappeared between the mid-18th and 19th centuries. In this case, we can now say that the longevity of the Red Spot exceeds 190 years.”
The permanent stain persisted for about 81 years, and none of the drawings the team analyzed mentioned a specific color for the storm, according to the study authors.
“It has been very motivating and inspiring to turn to the notes and drawings of Jupiter and its permanent spot made by the great astronomer (Cassini), as well as to his articles from the second half of the 17th century describing the phenomenon,” Sánchez-Lavega said. “Others before us had explored these observations, and now we have quantified the results.”
While examining historical data, the researchers also explored the origin of the storm by running simulations on supercomputers using models of the behavior of vortices in Jupiter’s atmosphere.
The team ran simulations to see whether the Great Red Spot formed from a gigantic superstorm, the merger of smaller vortices produced by Jupiter’s intense, alternating winds, or an instability of the winds that could produce an atmospheric storm cell. A storm cell is an air mass sculpted by ascending and descending wind currents that move as a single entity.
Vincenzo Pinto/AFP/Getty Images
Visitors to the Vatican Museum in 2010 were able to view a series of 1711 paintings by Donato Creti. The third painting from the right depicts Jupiter in the night sky.
Although the first two scenarios resulted in cyclones, they differed in shape and other features seen in the Great Red Spot.
“We also believe that if any of these unusual phenomena had occurred, its consequences in the atmosphere should have been observed and reported by astronomers of the time,” Sánchez-Lavega said.
But researchers believe the persistent atmospheric storm cell, resulting from intense wind instability, produced the Great Red Spot.
The storm measured about 24,200 miles (about 39,000 kilometers) at its longest point, according to 1879 data, but it shrank and rounded over time, and now measures about 8,700 miles (14,000 kilometers).
Previous research, published in March 2018, showed that the Great Red Spot grows larger as its size decreases overall. The 2018 study also used archival data to study how the storm evolved over time.
Data from modern space missions, such as NASA’s Juno space probe, have given astronomers unprecedented insight into the storm’s shape.
“Various instruments aboard the Juno mission orbiting Jupiter have shown that the (Great Red Spot) is shallow and thin compared to its horizontal dimension, as vertically it is about 500 km (310.7 miles) long “said Sánchez-Lavega. .
In the future, researchers will attempt to recreate the storm’s rate of shrinkage over time to understand the processes that keep the storm stable, as well as to determine whether it will persist for years or disappear when it reaches a certain size – which could have been the case. comes out of Cassini’s Permanent Spot.
“I love papers like this that delve deeper into pre-photographic observations,” said Michael Wong, a research scientist at the University of California, Berkeley. and co-author of the 2018 paper, after reading Sánchez-Lavega’s research. “(Our) paper used tracking data dating back to 1880, but Sánchez-Lavega’s new paper went further back and used data from hand drawings. The supplementary materials for this article are also excellent.
Wong was not involved in the new study.
“We have much to learn about these planets by making continuous, long-term observations of their weather and climate. »