The Venus Cloud Discontinuity

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The Venus Cloud Discontinuity

Post by hazarry »

Space Weather News for June 7, 2022

THE VENUS CLOUD DISCONTINUITY: Something big is happening in the atmosphere of Venus. A massive wall of acid clouds is racing around the second planet, possibly spinning up Venus's entire atmosphere. The structure is so big, amateur astronomers can see it from Earth.

A towering wall of acid clouds is racing through the atmosphere of Venus. Luigi Morrone photographed it from Agerola, Italy, on June 4th:
luigi-morrone-20220604_IR_Lmorr_1654505899_lg.jpg (62.51 KiB) Viewed 778 times

"It's called the Venus Cloud Discontinuity," says Morrone, who is part of an international network of amateur astronomers who have been tracking the massive structure. "I used a 14-inch Celestron telescope to record the discontinuity twice in 20 minutes."

The Venus Cloud Discontinuity is a relatively new discovery, photographed by Japan's Venus orbiter Akatsuki in 2016 and first spotted by JAXA scientist Javier Peralta. The massive structure cuts vertically across Venus's equator, stretching almost 5000 miles from end to end, and circles the planet faster than 200 mph, making one lap every ~5 Earth days.

Researchers following up on the discovery soon stumbled onto another surprise. Older photographs of Venus showed it, too. "[The Cloud Discontinuity] is a recurrent phenomenon that has gone unnoticed since at least the year 1983," they wrote in a May 2020 Geophysical Research Letter.

How do you overlook something so big? Visually, the Cloud Discontinuity is hidden underneath Venus's opaque cloudtops. To see it, you have to use an infrared filter, which reveals heat trickling up from below. Indeed, this is how amateurs are tracking the disturbance: "I used a Baader SLOAN 820-920nm near-infrared filter," notes Morrone.

Researchers still aren't sure what the Cloud Discontinuity is. "This atmospheric disruption is a new meteorological phenomenon, unseen on other planets. Because of this it is difficult to provide a confident physical interpretation," says Peralta. Numerical simulations suggest that it might be some kind of exotic nonlinear Kelvin wave; the jury's still out.

Whatever it is, the structure might help solve a longstanding mystery: Why does Venus's atmosphere rotate so much faster than the planet itself? The hot, deadly air on Venus spins nearly 60 times faster than its surface, an effect known as "super-rotation." Venus's Cloud Discontinuity could be assisting the spin-up by transporting angular momentum from the deep atmosphere to the cloudtops.

Amateur astronomers, if you would like to monitor this phenomenon, check out the preprint "Amateur Observers Witness the Return of the Venus Cloud Discontinuity," which discusses observing techniques. Venus is waiting in the morning sky.
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