Astronomers detect mysterious dark spot with new feature on Neptune

livemint.com:

CNN. The planet also has an unexpected bright companion. In a new research published in the journal Nature Astronomy, lead study author Patrick Irwin said he has always wondered since the first discovery of a dark spot what these elusive dark features are.

The space-based observatories observed that these dark spots, swirling in the blue planet's atmosphere, are like vortex storms. The astronomers said it was the first time that an Earth-based telescope gas had seen it on Neptune planet, CNN reported. An ice giant ‘Neptune’ has had multiple storms observed by Hubble over the past few years.

However, all the storms followed a pattern of appearing and disappearing which makes them difficult to study, as per CNN reports. Notably, astronomers had observed a gigantic storm system about the size of Earth near Neptune’s equator in 2017. The massive storm system was about 9,000km in length, or one-third the size of Neptune’s radius, spanning at least 30 degrees in both latitude and longitude.

At that time, de Pater thought it was the same Northern Cloud Complex seen by the Hubble Space Telescope in 1994, after the iconic Great Dark Spot, imaged by Voyager 2 in 1989, had disappeared. However, de Pater said measurements of its locale did not match, signaling that this cloud complex was different from the one Hubble first saw more than two decades ago. As with every planet, winds in Neptune’s atmosphere vary drastically with latitude, so if there is a big bright cloud system that spans many latitudes, something must hold it together, such as a dark vortex.