Subscribe to CNN’s Wonder Theory science newsletter. Explore the universe with news about fascinating discoveries, scientific advances and more.
CNN
—
Jupiter’s iconic Great Red Spot is a massive storm that has swirled in the atmosphere of the solar system’s largest planet for years.
However, astronomers have debated how old the vortex really is, as well as when and how it formed. Some experts believed it was centuries old and was first observed by Italian astronomer Giovanni Domenico Cassini in the 17th century, while others thought the storm was more recent.
New research now suggests that the Great Red Spot formed about 190 years ago, meaning that Cassini observed something else on Jupiter in 1665. And although the storm is younger than previously believed, the storm remains the largest and longest-lived vortex known in our area. Solar system, according to researchers.
A study detailing the findings was published June 16 in the journal Geophysical Research Letters.
Jupiter’s striking appearance is characterized by streaks and spots composed of bands of clouds surrounding the planet and cyclonic storms. Its colors come from the composition of the various atmospheric layers, which NASA says are individually made of ammonia, water ice, sulfur and phosphorus. Fast jet streams shape and stretch the clouds into long bands.
Cyclonic storms on Jupiter can last for years because the gaseous planet has no solid surface to slow down the storm.
The Great Red Spot is a massive vortex in Jupiter’s atmosphere that NASA says is about 10,000 miles (16,350 kilometers) wide, which is similar to the diameter of Earth. The storm rises more than 200 miles (322 kilometers) high.
Screaming winds are moving at 280 miles per hour (450 kilometers per hour) along the storm’s boundary. And its characteristic red hue comes from atmospheric chemical reactions.
The iconic feature is visible even through small binoculars.
And it sounded similar to the dark oval at the same latitude that Cassini first spotted when looking through his telescope in the mid-17th century. He labeled the object he saw the “Permanent Spot” and Cassini and other astronomers observed it until 1713, when they lost sight of the storm.
Then, in 1831, astronomers spotted a large oval storm at the same latitude on Jupiter that persisted and is still observed today. But astronomers have long wondered if it was possible that the storms were the same phenomenon, or two different eddies that appeared in the same place more than a century apart.
A team of researchers seeking to solve this mystery collected a wealth of data and analyzed historical drawings and images that show the structure, location and size of the site over time. The data was used to create numerical models that recreated the storm’s potential longevity.
Images by Ann Ronan/The Print Collector/Getty Images
Astronomer Giovanni Domenico Cassini first observed what he called the “Permanent Spot” on Jupiter in 1665. New research suggests that the Great Red Spot formed about 190 years ago, meaning that Cassini was observing something else on the planet in the 17th century.
“From measurements of magnitudes and motions, we conclude that it is highly unlikely that the current Great Red Spot is the ‘Permanent Spot’ observed by Cassini,” said study leader Agustín Sánchez-Lavega, professor of applied physics at the university. Basque Country in Bilbao, Spain in a statement. “The ‘permanent spot’ probably disappeared sometime between the middle of the 18th and 19th centuries, in which case we can now say that the lifetime of the Red Spot exceeds 190 years.”
The persistent patch persisted for about 81 years, and none of the drawings the team analyzed indicated any particular color of the storm, according to the study authors.
“It was very motivating and inspiring to turn to the notes and drawings of Jupiter and its permanent spots made by the great astronomer (Cassini) and to his papers from the second half of the 17th century describing this phenomenon,” Sánchez-Lavega said. “Others have explored these observations before us, and we have now quantified the results.”
While sifting through historical data, the scientists also explored how the storm formed by running supercomputer simulations using models of the behavior of vortices in Jupiter’s atmosphere.
The team ran simulations to determine whether the Great Red Spot formed from a gigantic superstorm, from the merging of smaller eddies produced by Jupiter’s intense and alternating winds, or from wind instabilities that could form an atmospheric storm cell. A storm cell is an air mass formed by updrafts and downdrafts that moves as a single entity.
Vincenzo Pinto/AFP/Getty Images
Visitors to the Vatican Museum in 2010 were able to observe a series of paintings from 1711 by Donato Creti. The third image from the right shows Jupiter in the night sky.
While the first two scenarios resulted in cyclones, they differed in shape and other characteristics witnessed in the Great Red Spot.
“We also believe that if any of these unusual phenomena occurred, it or its consequences in the atmosphere must have been observed and reported by astronomers at the time,” Sánchez-Lavega said.
However, scientists believe that a persistent atmospheric storm cell that formed due to intense wind instability created the Great Red Spot.
The storm measured about 24,200 miles (about 39,000 kilometers) at its longest point, according to data from 1879, but has shrunk and rounded over time, and is now about 8,700 miles (14,000 kilometers).
Previous research, published in March 2018, showed that the Great Red Spot is growing as it shrinks overall. A 2018 study also used archival data to study how the storm changed over time.
Data from modern space missions, such as NASA’s Juno probe, have given astronomers unprecedented insight into the shape of the storm.
“Various instruments aboard the Juno mission in orbit around Jupiter showed that (the Great Red Spot) is shallow and thin compared to its horizontal dimension, as it is about 500 km (310.7 miles) long vertically,” Sánchez-Lavega said . .
In the future, researchers will try to reconstruct the storm’s rate of contraction over time to understand the processes that keep the storm stable, as well as determine whether it will persist for years to come or disappear when it reaches a certain size — which could be the fate of Cassini’s Permanent Spot.
“I love articles like this that delve into pre-photographic observations,” said Michael Wong, a scientist at the University of California, Berkeley. and co-authored the 2018 paper after reading Sánchez-Lavega’s research. “(Our) paper used tracking data up to 1880, but Sánchez-Lavega’s new paper went further 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 a lot to learn about these planets by observing their weather and climate continuously and long-term.”