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When it comes to planets with large spots, you might think of Jupiter and its famous Great Red Spot.
But a study has shed new light on a lesser-known large spot in our solar system.
Using the European Space Agency’s Very Large Telescope (VLT), scientists have observed a large dark spot on Neptune about 10,000 kilometers in diameter – 20 times the size of the Grand Canyon.
This great void has an unexpectedly smaller bright spot next to it, and scientists still don’t know how it formed.
Professor Patrick Irwin, a professor at the University of Oxford and lead researcher on the study, told MailOnline: ‘We know that these dark spots are anticyclonic vortices, just like Jupiter’s Great Red Spot, but how and why they form is not clear. clearly. clearly understood.’
Using the European Space Agency’s Very Large Telescope (VLT), scientists have observed a large dark spot on Neptune about 10,000 kilometers in diameter – 20 times the size of the Grand Canyon.
Neptune’s dark spot was first observed by NASA’s Voyager 2 spacecraft in 1989.
However, it is not a permanent phenomenon and disappears every few years. which makes observing them in sufficient detail difficult.
In 2018, NASA’s Hubble Space Telescope discovered the dark spot again.
“Since Voyager 2 GDS, several dark spots have been observed by the Hubble Space Telescope,” said Professor Irwin.
“These patches seem to form randomly every few years at northern or southern latitudes and then drift toward the equator, eventually disappearing after about an Earth year.”
In this new study, Professor Irwin and his team set out to study the dark spot from the ground for the first time.
The VLT is equipped with a Multi Unit Spectroscopic Explorer, which splits the sunlight reflected from Neptune into its component colors and wavelengths.
This allowed the team to study the site in more detail than ever before.
“I am absolutely thrilled to not only have been able to make the first detection of a dark spot from the ground, but also capture a reflection spectrum of such a feature for the very first time,” said Professor Irwin.
Different wavelengths probe different depths in Neptune’s atmosphere, meaning the spectrum can infer the size and height of the dark spot, as well as its chemical composition.
The new observations rule out the possibility that dark spots are caused by the ‘clearing up’ of the clouds.
The VLT is equipped with a Multi Unit Spectroscopic Explorer, which splits the sunlight reflected from Neptune into its component colors and wavelengths
Instead, researchers think that dark spots are likely the result of ice and haze mixing in the atmosphere, causing air particles to darken.
The observations also yielded a surprising result.
“In this process, we discovered a rare, deep, bright cloud type that had never been identified before, even from space,” said Dr. Michael Wong, co-author of the study from the University of California, Berkeley.
These rare clouds explain the bright spot next to the larger dark spot, according to the researchers.
The team hopes the findings will demonstrate the capabilities of Earth-based telescopes.
“This is an astonishing increase in humanity’s ability to observe the cosmos,” Dr Wong added.
‘Initially, we could only detect these spots by sending a spacecraft such as Voyager there. Then we got the ability to distinguish them from a distance with Hubble.
“Finally, technology has advanced to make this possible from the ground up. This could put me out of work as a Hubble observer!’