Using data from the WFC3 / UVIS instrument aboard the NASA / ESA Hubble Space Telescope, a team of astronomers has measured the horizontal winds in Jupiter’s Great Red Spot. Analyzing long-term data from the limits of the colossal storm, they found that wind speeds increased by as much as 8% between 2009 and 2020; in contrast, winds near the innermost region of the storm move significantly slower (about 2.5 km / h per Earth year).
Big changes in the massive storm
The storm, larger than our own planet Earth, has been observed for more than 150 years and the speed of its storms is spectacular compared to our planet.
Wind speed varied depending on when Hubble was looking at the storm, but the telescope recorded long-term increases in the speed of rotation of the outer ring, without question. The average wind speed in the outer ring currently easily exceeds 360 km / h, whereas a decade ago the range often dropped to 324 km / h.
“When I initially saw the results, I asked ‘Does this make sense?’ No one’s seen this before, ‘”said Michael Wong, a planetary scientist at the University of California at Berkeley and a leader of the work that publishes the journal Geophysical Research Letters.
But there was no room for error. The data was fine. Since we don’t have planes in orbit that monitor every movement in real time, it is not possible to continuously measure winds, but Hubble is the only space telescope with the ability to capture the planet’s winds with this level of detail.
Thus, the precision of the Hubble Space Telescope and the records of long-term observations have allowed for strong confirmation, along with an analysis of software data that tracked tens of thousands to hundreds of thousands of wind vectors (directions and speeds) during the observations of the largest planet in the solar system.
Jupiter’s Great Red Spot is getting faster but scientists are still unclear about what this change in speed actually means for the great storm.
‘This is difficult to diagnose, as Hubble cannot see the bottom of the storm very well. Everything below the clouds is invisible in the data. But it is an interesting piece of information that can help us understand what feeds the Great Red Spot and how it maintains energy, “Wong clarifies.
The Great Red Spot is an outcrop of material from the interior of Jupiter. Astronomers have found that it is dwindling and becoming more circular than oval in observations spanning more than a century. Now this change in wind speed. Clearly, the legendary storm will have to be followed closely to draw conclusions about the underlying physics that drive and sustain planetary storms.
“There is still a lot of work to do to fully understand it,” the researchers conclude.
Referencia: Michael H. Wong et al, Evolution of the Horizontal Winds in Jupiter’s Great Red Spot from One Jovian Year of HST/WFC3 Maps, Geophysical Research Letters (2021). DOI: 10.1029/2021GL093982
