Centuries ago, a huge red spot on Jupiter disappeared. But years later a new one was born.
Today we know this striking feature as the ‘Great Red Spot’, a swirling storm wider than Soil. Curiously, earlier astronomers, such as Giovanni Domenico Cassini in 1665, also observed a colossal red storm at the same latitude on Jupiter, raising the possibility that it is actually the same storm.
However, in newly published research, astronomers scoured historical drawings and early telescope observations of Jupiter to conclude that the current spot is indeed a separate storm from its predecessor, incorrectly known as the ‘Permanent Spot’. It probably disappeared between the mid-18th and 19th centuries.
“What is certain is that no astronomer of that time reported any location at that latitude for 118 years,” Agustín Sánchez-Lavega, a planetary scientist at the University of the Basque Country in Spain, told Mashable.
NASA scientist viewed first Voyager images. What he saw gave him chills.
Then, in 1831, astronomers again began to see a striking red spot. The new research, published in Geophysical research lettersconcludes that this newest site is at least 190 years old.
Mashable speed of light
That’s an impressive storm. Not only has it been spinning counterclockwise for almost two centuries, but it also has wind speeds that reach around 400 miles per hour. Planetary scientists at NASA and elsewhere are trying to understand what gives the space storm its vibrant red hue.
Century-old documentation of the Permanent Spot also shows that it was much smaller than the Great Red Spot in the 19th century (and later), meaning this earlier storm should have tripled in size. But that’s not something astronomers have ever seen during a storm on Jupiter, Sánchez-Lavega explained.
Images a, b and c show the “Permanent Spot”, drawn by Italian astronomer Giovanni Domenico Cassini in 1677, 1690 and 1691 respectively. Image d shows a view of the Great Red Spot in 2023.
Credit: GD Cassini / Eric Sussenbach / AGU
a: A 1711 painting of Jupiter by Donato Creti showing the permanent spot. b: A drawing by the French artist EL Trouvelot from November 1880, showing the Great Red Spot. c: A drawing by TG Elger from November 1881 showing the Great Red Spot.
Credits: Donato Creti / EL Trouvelot / TG Elger
You may wonder how the Great Red Spot, so unique in color and size, came to be. You are not alone. To find out, the research team also ran computer simulations based on the behavior of eddies (or storms) in Jupiter’s atmosphere. The most compelling result – which created a larger ‘proto-Great Red Spot’ that would have shrunk into a more compact storm – was unstable winds and atmospheric disturbances in this region of Jupiter’s atmosphere. Another leading candidate was the possibility of several storms merging, but that didn’t produce anything resembling the Great Red Spot.
For more than 150 years, the Great Red Spot has continued to shrink. In 1879, when it looked more like a sausage, it was about 24,000 miles (39,000 kilometers) across. Now it is 14,000 kilometers wide, which is about the same size as its predecessor. The next stages of the site are uncertain.
The Great Red Spot, as seen in April 2017, with Earth over it.
Credit: NASA/JPL-Caltech/SwRI/MSSS/Christopher Go
‘We don’t know what the future of the [Great Red Spot] That is the case,” Sánchez-Lavega said. If it continues to contract, it may fall apart. Or, he added, “It can reach a stable size and last a long time.”
One thing is certain: from our perch, hundreds of millions of miles away, we will be watching.