The big dark spot (middle high) and its smaller companion (top right) on Neptune as seen by the Hubble Space Telescope in 2020. The big dark spot – found there in 2018 – unexpected direction and moved back as it came. The smaller storm is thought to be a fragment of the larger storm. Image via NASA / ESA / STScI / MH Wong (University of California, Berkeley) / LA Sromovsky / PM Fry (University of Wisconsin-Madison).
Like its big sisters Jupiter, Saturn and Uranus, Neptune has major storms in the churning atmosphere seen in the most powerful telescopes on Earth. Scientists have been tracking one of Neptune’s big spots, first spotted by the Hubble Space Telescope in September 2018. This time, the storm did something unexpected. He changed the direction, saving himself from the expected separation, at least for now. The remarkable development was announced by Hubble astronauts on December 15, 2020 and demonstrated at the fall meeting of the American Geophysical Union on that same day.
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This storm Neptune is wider than the Atlantic Ocean, at 4,600 miles (7,403 km) across. This is the fourth dark storm on Neptune that Hubble has seen since 1993. Previously, two other similar storms, including the Great Dark Spot Neptune, were seen nearby with the Voyager 2 spacecraft back in 1989 to Neptune’s historic flight. Unfortunately, they were gone before Hubble came on the scene in 1990 and could take a look.
This is the smaller dark place, which – according to the scientists – tends to break a fragment off the larger dark place. Image via NASA / ESA / STScI / MH Wong (University of California, Berkeley) / LA Sromovsky / PM Fry (University of Wisconsin-Madison).
The change in direction of this latest storm was not the only unusual thing about it. It was obvious too lack of smaller, bright feather clouds, often seen above Neptune’s dark spots. According to the scientists, these clouds disappeared when the dark place stopped moving south. The clear clouds are made up of methane ice crystals that form when gases are moved up over the dark spots and frozen into crystals.
There was also a smaller companion in the dark area – known as “dark spot jr.” – first seen in January 2020, which astronomers believe has broken away from the main storm. Eventually this smaller space disappeared. Michael Wong of the University of California, Berkeley, explained:
We are excited about these ideas because this smaller dark chip may be part of a dark space chaos process. This is a process that has never been seen before. We saw other dark spots disappear, and they are gone, but we did not see anything disturbing it, even as would be expected in computer simulations.
The new larger storm began its life in the northern hemisphere of Neptune and then began to gradually move to the southern hemisphere of the planet. As can be seen in the observation of other such storms, it is there that they begin to separate. But not this time. Instead, the storm was observed to have slowed and changed direction by August 2020, moving back north from where it came from. This was the first time such behavior had been noticed in 30 years of Hubble observations.
Michael Wong at the University of California, Berkeley, lead author of the new paper on the dark spots at Neptune. Image through University of California, Berkeley.
Interestingly, the less dark place appeared around the same time the bigger storm turned back and started going back to where it had come from. This new location was about 3,900 miles (6,276 km) across, and appeared on the side of the most overlooking Neptune’s equator. This was the area where some computer simulations suggested that intrusion into the larger space could occur, but it did not appear to be the time. Wong said:
When I first saw the small space, I thought the big one was annoying. I didn’t think another fortune was forming because the little one is further towards the equator. So it is within this unstable area. But we cannot prove a connection between the two. It remains a complete mystery.
It was also in January [2020] that the dark fortune stopped him and he began to move north again. Possibly peeling that cookie was enough to stop it from moving towards the equator.
Neptune storms are similar to those of the gas giants and other ice giants (Neptune is an ice giant) and can grow in size to damage the largest fingers or cyclones on Earth, growing to the size of the ice giant. Land itself. Unlike terrestrial hurricanes, they are high-pressure systems that form at mid-latitudes before moving closer to the equator. In the northern hemisphere, they move clockwise due to the Influence of Coriolis. However, this effect weakens as storms approach the equator, eventually causing the storms to disintegrate.
That is the general situation that plays out as Neptunian storms develop and then break apart. However, in this case, the storm did not enter the “killing zone” outside the equator. As Wong said:
It was very interesting to see this one act as it is supposed to be involved and then all of a sudden it just stops and turns back. That was a surprise.
The large dark spot on Neptune as seen by Voyager 2 in 1989. The white feather clouds above it are made up of methane ice crystals. Image via NASA / JPL / Wikipedia.
It is not yet known if there is a dark spot jr. they also survived, but scientists continue to study the data from Hubble. The new observations also provide valuable insight into how the Neptune atmosphere as a whole behaves.
Hubble has played a key role in observing these spots on Neptune, especially since no other spacecraft has visited the planet since Voyager 2. According to Amy Simon at the Goddard Space Flight Center at NASA:
We wouldn’t know anything about these latest dark spots if it weren’t for Hubble. We can now follow the great storm for years and look at its entire life cycle. 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 discovered.
Until a new mission is launched (hopefully) eventually, telescopes like Hubble will keep an eye on Neptune’s secret dark places.
Bottom line: A huge, dark storm on Neptune changed direction unexpectedly, saving itself from imminent destruction in the process. It may also have produced a smaller companion storm.
Source: Npt-2018 Neptune: The Immortal Dark Vortex
Through NASA
