A dark storm on Neptune returns direction, possibly stripping a cookie

Astronauts using NASA’s Hubble Space Telescope watched a mysterious dark fortune on Neptune suddenly steering away from a seeming death on the vast blue planet.

The storm, which is wider than the Atlantic Ocean, was born in the northern hemisphere of the planet and was discovered by Hubble in 2018. Observations a year later showed that it began to move south to attack of the equator, where these storms are expected to disappear. To the surprise of viewers, Hubble saw the direction of change of the vortex by August 2020, doubling back north. While Hubble has discovered similar dark places over the past 30 years, this invisible atmospheric behavior is something new to behold.

Equally interesting, the storm was not alone. Hubble saw another smaller dark spot in January this year that appeared for some time close to its larger cousin. It may have been a piece of the great vortex that broke away, moved away, and subsequently disappeared.

“We’re excited about these ideas because this smaller dark chip may be part of a dark space riot process,” said Michael H. Wong of the University of California at Berkeley. never seen. We’ve seen other dark spots disappear, and they’re gone, but we haven’t seen anything that bothers him, even as would be expected in computer simulations. “

The massive storm, at 4,600 miles across, is the fourth darkest place Hubble has seen on Neptune since 1993. Two more dark storms were discovered by the spacecraft Voyager 2 in 1989 when it flew with the entire planet out, but they had disappeared before Hubble could see them. Since then, only Hubble has been so sharp and sensitive in visible light to track these accessible features, which have appeared in sequence and then gone over about two years. every man. Hubble discovered this latest storm in September 2018.

Wicked weather

Neptune’s dark vortices are high-pressure systems that can be at the center of latitudes and then can move toward the equator. They start out stable as a result of Coriolis forces, which cause storms in the northern hemisphere to rotate clockwise, due to the rotation of the planet. (These storms are unlike hurricanes on Earth, which orbit counterclockwise because they are low-pressure systems.) However, as a storm moves toward the equator, the effects of Coriolis weaken and the storm dissipates. In computer simulations with several different crews, these storms follow a virtually direct path to the equator, so that there is no Coriolis effect to hold them together. Unlike the symbols, the latest major storm did not move into the equatorial “killing zone”.

“It was very interesting to see this one act as it deserves to be in place and then all of a sudden it just stops and turns back,” Wong said. no wonder. “

Dark Spot Jr.

Hubble’s observations also revealed that the cascading reversal of the dark vortex coincided with the emergence of a new space, informally regarded as “dark spot jr.,”. The most recent location was slightly smaller than its cousin, measuring about 3,900 miles across. It was close to the side of the main dark spot opposite the equator – the place where some symbols would appear to start.

However, the time when the spot appeared was less remarkable. “When I first saw the small space, I thought the big one was annoying,” Wong said. “I didn’t think other fortunes were forming because the little one is further towards the equator. So it’s within this unstable area. But we can’t confirmation that the two are related.It remains a complete mystery.

“It was also in January that the dark fortunes stopped him from moving and he started moving north again,” Wong said. “Perhaps by peeling off that crumb, that was enough to stop it from moving toward the equator.”

The researchers continue to study more data to determine if there are remnants of dark spot jr. they continued through the rest of 2020.

Dark storms still rare

It’s still a mystery how these storms shape, but this latest big dark fortune is the best study to date. The dark appearance of the storm may be due to elevated dark cloud cover, and may tell astronomers the vertical structure of the storm.

Another unusual feature of the dark space is that it is not surrounded by clear companion clouds, which were present in Hubble images taken when the fortune was discovered in 2018. Apparently, the clouds disappeared when fortune halted his journey south. The clear clouds form when the flow of air is diverted and moved up above the vortex, causing gases to freeze into methane ice crystals. Lack of clouds could reveal information about how spots develop, say researchers.

A weather observation of the outer planets

Hubble broke many of the images of the dark spots as part of the Atmospheres Outer Planet Legacy (OPAL) program, a long-running Hubble project, led by Amy Simon of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, which will capturing world maps every year. of planets outside our solar system when they are closer to Earth than their orbit.

OPAL’s main objectives are to study long-term seasonal changes, as well as to capture relatively temporary events, such as the appearance of dark spots on a possible Neptune or Uranus. These dark storms could be so great that some of them could have appeared and eroded through multi-year gaps in Hubble’s views on Neptune. The OPAL program ensures that astronauts do not miss another.

“We wouldn’t have known anything about those latest dark spots if it weren’t for Hubble,” Simon said. “We can now follow the great storm for years and look at its entire lifecycle. If we didn’t have Hubble, we might think that the Great Dark Spot that Voyager saw in 1989 is still in Neptune, just like Jupiter’s Red Spot. And, we wouldn’t know about the other four places Hubble has discovered. “Wong will present the team’s findings Dec. 15 at the fall meeting of the Geophysical Union America.

The Hubble Space Telescope is a project of international collaboration between NASA and ESA (European Space Agency). The telescope will be controlled by NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science activity. STScI is run for NASA by the Association of Universities for Research in Astronomy in Washington, DC

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