In 1665, Italian astronomer Giovanni Cassini observed a huge dark spot on Jupiter that he named “the Eternal Spot.” (British scientist Robert Hooke may have discovered it a year earlier, in 1664, but that’s beside the point.) While astronomers have remained mystified about the spot’s whereabouts for centuries, we’ve always suspected that the original “Eternal Spot” was the Great Red Spot (a giant storm on Jupiter’s surface) that we know and love today.
Well, we were wrong: new research on the Great Red Spot suggests it’s likely a newer, younger storm.
Since the first observation of the “permanent spot” in the 17th century, we have forgotten about it. It was last seen in 1713. More than a century passed before a new spot was found, which happened to be at the same latitude as the first one. This spot, discovered in 1831, is what we know today as the Great Red Spot.
“From our measurements of its size and motion, we infer that it is highly unlikely that the current Great Red Spot is the ‘permanent spot’ observed by Cassini,” said study leader Agustín Sánchez Lavega, a planetary scientist at the University of the Basque Country in Bilbao, Spain. statement“The ‘permanent spot’ probably disappeared sometime between the mid-18th and 19th centuries, which would mean the lifespan of the Red Spot would be greater than 190 years.”
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Using data on the Great Red Spot’s evolution over time, Sanchez-Lavega and his colleagues ran computer simulations to determine how the vortices formed: the leading theory is that they were caused by wind instabilities that ultimately created the “elongated atmospheric cells” we see today.
What we know for sure about the Great Red Spot is that it’s shrinking. In 1879, observations put its size at 24,200 miles (39,000 kilometers) along its longest axis; now, its longest axis is 8,700 miles (4,000 kilometers) wide. The team plans to run further simulations to predict whether the Great Red Spot will eventually disappear, like Cassini’s permanent spot, and whether it will be reborn as a new vortex, perhaps in a few centuries.
The team’s research was published June 16 in the journal Neuroscience. Geophysical Research Letters.
Originally posted Space.com.