“No one has seen this before” – Hubble shows winds in Jupiter’s great red spot are accelerating

Winds at the outer edge “win the race” in this huge storm system

Listen, racing fans! The innermost route no longer has a predictable advantage. In Jupiter‘s Great Red Spot, a storm that has raged for centuries, the speed in its “outer lane” moves faster than the inner lane – and continues to pick up speed. Analyzing long-term data in this high-speed ring, the researchers found that winds increased by up to 8% from 2009 to 2020. These findings could only be made with Hubble: the telescope accumulated over 10 years of regular observations, acting as a “storm watcher” for the planets in our solar system.

Like the speed of a racing driver, the winds in the “lane” furthest from Jupiter’s Great Red Spot are accelerating – a discovery made possible only by Nasa‘s The Hubble Space Telescope, which has watched the planet for more than a decade.

Researchers analyzing Hubble’s regular “storm reports” found that the average wind speed just inside the storm’s limits, known as the high-speed ring, increased by up to 8%. 2009-2020. In contrast, the winds near red the innermost region of the spot move much more slowly, like someone sailing lazily on a sunny Sunday afternoon.

The massive storm’s purple-colored clouds spin counterclockwise at speeds over 400 miles per hour – and the vortex is larger than Earth itself. The red spot is legendary in part because humans have observed it for over 150 years.

“When I saw the results for the first time, I asked ‘Does this make sense? “No one has ever seen this before,” said Michael Wong of the University of California, Berkeley, who led the analysis published in Geophysical research letters. “But it’s something only Hubble can do. Hubble’s longevity and continuous observations make this revelation possible.

We use satellites and planes orbiting the Earth to closely follow major storms on Earth in real time. “Because we don’t have a storm chaser plane in Jupiter, we can’t continuously measure the winds there,” said Amy Simon of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who helped to the research. “Hubble is the only telescope that has the kind of temporal coverage and spatial resolution that can capture Jupiter’s winds in this detail.”

The change in wind speed they measured with Hubble is 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’s happened,” Simon said. “With Hubble, we have the precision we need to spot a trend.” Hubble’s continuous monitoring allows researchers to review and analyze its data very precisely as they add to it. The smallest features Hubble can reveal in the storm are only 105 miles in diameter, about double the length of the state of Rhode Island.

Each loop in this video represents approximately 10 Earth hours or a Jupiter day, what it would look like if the Great Red Spot were constantly illuminated. By analyzing this dataset from the NASA / ESA Hubble Space Telescope, the researchers were able to simulate what the wind flow looks like around Jupiter’s Great Red Spot: Just south of the Great Red Spot is a jet towards east and at the southern border is a jet west. Credit: NASA, ESA, MH Wong (UC Berkeley)

“We find that the average wind speed in the Great Red Spot has increased slightly over the past decade,” Wong added. “We have an example where our analysis of the two-dimensional wind map revealed abrupt changes in 2017 when there was a major convection storm nearby.”

To better analyze the generosity of Hubble’s data, Wong took a new approach to its data analytics. He used software to track tens to hundreds of thousands of wind vectors (directions and speeds) each time Jupiter was observed by Hubble. “It gave me a much more consistent set of speed metrics,” Wong explained. “I also performed a battery of statistical tests to confirm if it was justified to call it an increase in wind speed. He is.”

What does the increase in speed mean? “It’s hard to diagnose because Hubble can’t see the bottom of the storm very well. Anything below cloud tops is invisible in the data, ”Wong explained. “But it’s an interesting piece of data that can help us understand what fuels the Great Red Spot and how it maintains energy.” There is still a lot of work to be done to fully understand this.

This three-dimensional model of Jupiter was computer generated from a new global map of the planet that was taken by the Wide Field Camera 3 of the NASA / ESA Hubble Space Telescope on June 27, 2019, while the planet was 644 million kilometers from Earth. Credit: NASA, ESA, A. Simon (Goddard Space Flight Center), and MH Wong (University of California, Berkeley), M. Kornmesser

Astronomers have continued ongoing studies of the solar system’s “king” of storms since the 1870s. The Great Red Spot is an ascent of matter from inside Jupiter. If viewed from the side, the Storm would have a tiered wedding cake structure with high clouds in the center cascading down to its outer layers. Astronomers have noted that it decreases in size and becomes more circular than oval in observations spanning over a century. The current diameter is 10,000 miles in diameter, which means Earth could still enter it.

In addition to observing this legendary long-lasting storm, researchers observed storms on other planets, including Neptune, where they tend to roam the surface of the planet and disappear in just a few years. Research like this helps scientists not only learn more about individual planets, but also draw conclusions about the underlying physics that drives and sustains planetary storms.

Reference: “Evolution of horizontal winds in the great red spot of Jupiter from a Jovian year of HST / WFC3 charts” by Michael H. Wong, Philip S. Marcus, Amy A. Simon, Imke de Pater, Joshua W. Tollefson and Xylar Asay -Davis, August 29, 2021, Geophysical research letters.
DOI: 10.1029 / 2021GL093982

The majority of the data supporting this research comes from Hubble’s Outer Planets Atmospheres Legacy (OPAL) program, which provides annual Hubble global views of the outer planets that allow astronomers to search for changes in storms, winds and the clouds of the planets.