Amateur Astronomers See 'Blades' on Jupiter's Great Red Spot

Amateur astronomer Anthony Wesley captured this view of Jupiter and its Great Red Spot on May 19, 2019, from the town of Rubyvale in Queensland, Australia.
Amateur astronomer Anthony Wesley captured this view of Jupiter and its Great Red Spot on May 19, 2019, from the town of Rubyvale in Queensland, Australia. (Image credit: Anthony Wesley)

What's in a name? Well, for the amateur astronomers and scientists fixated on Jupiter, there's been a recent need to describe its iconic storm as more than just a great red spot.

Here on Earth, storms are born and then they disappear. And though it has lingered for hundreds of years, Jupiter's famous vortex may be approaching the end of its life span, too, as strange as that may seem.

The Great Red Spot — GRS for short — is getting smaller. The system was once very elongated, which NASA scientist Glenn Orton joked "might have been better referred to as the Great Red Sausage" in a May 21 email to Orton added that the GRS has been shrinking at a pretty consistent rate. Recently, amateur astronomers viewed new formations, "blades" and "flakes," spinning off from the Great Red Spot. Some reports have called it an unraveling — while experts talked with wouldn't describe this activity that way, it's still very fascinating to watch. 

Related: Jupiter's Great Red Spot in Pictures

Anthony Wesley captured this view of Jupiter on May 22, 2019, from the town of Rubyvale in Queensland, Australia. (Image credit: Anthony Wesley)

From the Philippines, amateur astronomer Christopher Go observed a reddish extension on the left side of this counterclockwise-spinning storm when photographing Jupiter on Friday (May 17). 

To the south, in Australia, amateur astronomer Anthony Wesley captured one of these peculiar shapes coming off the spot two days later on Sunday (May 19), and then again on Wednesday (May 22). 

As they battle terrestrial weather conditions to keep an eye on the spot's changes from Earth, NASA's Juno mission studies it up close from orbit. The spacecraft arrived at Jupiter in July 2016, and is currently in its 19th perijove, or the point in the satellite's orbit nearest to Jupiter's center. Imagery from Juno's 17th and 18th observational flybys also show some of these flaky formations.

 Related: How NASA's Juno Mission to Jupiter Works (Infographic) 

The Juno mission captured this view at an altitude of about 16,709 miles (26,890 km) on Feb. 12, 2019.  (Image credit: NASA/SwRI/MSSS)

The red flakes lasted for more than a week. This is according to an emailed report by John Rogers of the British Astronomical Association, a network for amateur astronomers, from May 15. Scientists with Juno are preparing to study other aspects of the Great Red Spot when the probe flies over it again in July 2019.

But the mission has noticed these blade formations in the past. Orton told that Juno "observations sensitive to upper-level hazes have detected high-altitude 'flakes' or 'blades' detaching from the western side of the GRS," adding that this was a rare phenomenon up until 2017.

"Some observers implied that these [blades] were induced by the arrival of vortices in a jet just south of the GRS moving from east to west that enter a dark area surrounding it that is characterized by deeper clouds, known as the 'Red Spot Hollow,'" Orton said. "Stay tuned, as the dark region around the GRS is growing in length, and we'll see what happens next."

You can watch an animation of Jupiter's GRS changes made by Shinji Mizumoto for the Association of Lunar and Planetary Observers in Japan here.

Shinji Mizumoto created this timelapse animation of Jupiter's Great Red Spot, which combines many observations of the vortex from January to May 2019. Mizumoto posted this visual on ALPO-Japan, or Association of Lunar and Planetary Observers in Japan. (Image credit: Shinji Mizumoto/ALPO-Japan)

For now, Juno is focused on what's happening deeper within the GRS. One of Juno's instruments, the Microwave Radiometer, found that GRS "lasts as far down in the atmosphere as the MWR can detect," Orton said. So when Juno flies over it in July, priority will be given to the "gravity-sensing capability of the mission" that can give scientists a better idea about how far down Jupiter's famous beauty mark goes.

While it's not clear what these blades may mean about the Great Red Spot's longevity, the spot could be gone in 20 years. In a February 2018 interview with Business Insider, Orton said the GRS "will in a decade or two become the GRC (Great Red Circle) ... maybe sometime after that, the GRM [Great Red Memory.]" 

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Doris Elin Urrutia
Contributing Writer

Doris is a science journalist and contributor. She received a B.A. in Sociology and Communications at Fordham University in New York City. Her first work was published in collaboration with London Mining Network, where her love of science writing was born. Her passion for astronomy started as a kid when she helped her sister build a model solar system in the Bronx. She got her first shot at astronomy writing as a editorial intern and continues to write about all things cosmic for the website. Doris has also written about microscopic plant life for Scientific American’s website and about whale calls for their print magazine. She has also written about ancient humans for Inverse, with stories ranging from how to recreate Pompeii’s cuisine to how to map the Polynesian expansion through genomics. She currently shares her home with two rabbits. Follow her on twitter at @salazar_elin.