Gas giants appear to be losing gigantic storms every day. First, it was Jupiter, while not as famous, Neptune is going to be losing its own gigantic storm. Neptune's Great Dark Spot is noticeably shrinking.
This isn't the first of Neptune's Great Dark Spots that have disappeared over the years.
Great Dark Spot
Naming conventions for the gigantic storms haven't been very original. Jupiter's Great Red Spot has ten years left. Neptune's Great Dark Spot tend to have a much shorter lifespan. These storms were first spotted on Neptune in 1989 by NASA's Voyager 2.
That storm was large enough to cover the Atlantic Ocean, from the U.S. to Europe.
Several different spots have come and gone since the first was discovered. Neptune's current Great Dark Spot was first seen in 2015. Storms on Neptune usually last for a year, scientists estimate that Jupiter's Great Red Spot has been going since the 1600s.
Scientists initially believed that the storm would drift toward the equator then break up. The storm eventually made its way down to the South Pole and is slowly starting to fade away.
A lot of the information about Neptune comes from the observations from Voyager. Neptune is the farthest planet from the Sun. Other than the Voyager mission, Hubble is the only facility to have observed the storms on Neptune.
Dark Spot Mysteries
Not much is known about Neptune, and much less is known about its Dark Spot. It is thought that the storm could be a hole in the methane cloud deck of Neptune. This storm generates large white clouds made of frozen methane. The dark spot in the storm may contain hydrogen sulfide.
What may be making the Dark Spot darker than the rest of the storm isn't that it's dark, it's that it may be less bright than the rest of the atmosphere. Scientists still don't know how the storms are forming, and why they form.
"We have no evidence of how these vortices are formed or how fast they rotate," said Agustín Sánchez-Lavega from the University of the Basque Country to NASA. "It is most likely that they arise from an instability in the sheared eastward and westward winds."
Neptune's storms have not been uniform. The storms differ in terms of size, shape, and stability throughout the years. They're anticyclones like the storms on Jupiter but they have a much shorter lifespan, storms on Jupiter take decides to disappear.
This is the first of the dark sports to be photographed while it is dying.
