Jupiter’s Great Red Spot isn’t as permanent as we thought

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Subscribe to enjoy similar stories. Jupiter’s Great Red Spot—a rotating storm that is so large it could swallow Earth—isn’t what it used to be. Research has revealed that the crimson-hued spot visible today is, on average, larger than the one Italian astronomer Giovanni Cassini espied for the first time in 1665 and called the “Permanent Spot." Both Cassini’s spot and the current one are anticyclones, or vortexes of winds in high pressure areas.

Today’s spot swirls in the gas giant’s Southern Hemisphere, and its winds can reach speeds of nearly 300 miles an hour. But the 17th century tempest viewed by Cassini likely dissipated and was replaced, according to researchers from Spain, who found that observations of the storm’s size and motions from the mid-1600s and those of today’s storm don’t match. Indeed, astronomers lost track of Cassini’s spot after 1713, and it wasn’t until 1831 that observations of a storm on Jupiter resurfaced.

According to the new research, led by Agustín Sánchez‐Lavega, the storm observed in 1831 is the Great Red Spot we see today. The findings were published earlier this year in the journal Geophysical Research Letters. Sánchez‐Lavega, a physicist and planetary scientist at the University of the Basque Country in Bilbao, Spain, said it is reasonable to think that although such spots are long-lived, they can form, disappear and reform cyclically in the same area.