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Data accumulated from 2009 to 2020 by the Hubble Space Telescope suggest that the outer winds in Jupiter’s Great Red Spot have speeded up by about 8%, while the winds in the spot’s inner regions have slowed.
The change in wind speeds they have measured with Hubble amount to less than 1.6 miles per hour per Earth year. “We’re talking about such a small change that if you didn’t have eleven years of Hubble data, we wouldn’t know it happened,” said Simon. “With Hubble we have the precision we need to spot a trend.” Hubble’s ongoing monitoring allows researchers to revisit and analyze its data very precisely as they keep adding to it. The smallest features Hubble can reveal in the storm are a mere 105 miles across, about twice the length of the state of Rhode Island.
“We find that the average wind speed in the Great Red Spot has been slightly increasing over the past decade,” Wong added. “We have one example where our analysis of the two-dimensional wind map found abrupt changes in 2017 when there was a major convective storm nearby.”
The graphic above shows the different wind speeds between the spot’s inner and outer regions, not the increase in speed described in this press release.
To put it mildly, these results are uncertain. We simply could be seeing the long term random fluctuations in the storm, or the change could simply be a reflection of the data’s margin of error. Moreover, since the data covers only the top layer of the Great Red Spot, it tells us nothing about the storm’s deeper regions or its more fundamental origins.
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