Astronomers utilizing the European Southern Observatory’s Very Large Telescope in Chile have made a significant discovery on Neptune—a large and enigmatic dark spot. This finding is accompanied by an unexpected bright companion, as reported by CNN. The research has been published in the journal Nature Astronomy, and lead study author Patrick Irwin expressed his long-standing curiosity about these elusive dark features.
These dark spots, which appear to be swirling in Neptune’s blue atmosphere, resemble vortex storms. This is the first instance where Earth-based telescopes have observed these features on the distant planet, marking a notable milestone in planetary observation.
Neptune, known as an ice giant, has previously exhibited various storms that were studied using the Hubble Space Telescope over the years. However, these storms often followed patterns of appearing and disappearing, making their study complex, as reported by CNN.
In 2017, astronomers noted a massive storm system near Neptune’s equator, roughly the size of Earth. Spanning about 9,000 kilometers and covering around one-third of Neptune’s radius, this storm system extended across approximately 30 degrees in both latitude and longitude.
Initial assumptions suggested that this storm was linked to the Northern Cloud Complex observed by the Hubble Space Telescope in 1994, following the disappearance of the iconic Great Dark Spot, which had been imaged by Voyager 2 in 1989. However, measurements of its location did not align, indicating that this cloud complex was distinct from the one observed over two decades earlier.
Neptune’s atmospheric winds exhibit significant variations across different latitudes. Therefore, if a large bright cloud system spans multiple latitudes, there must be a force holding it together, such as a dark vortex. Otherwise, the clouds would disintegrate due to the shearing forces. This discovery highlights substantial shifts in Neptune’s atmospheric dynamics, possibly indicating a seasonal weather event that could occur every few decades.
Professor de Pater, a researcher in the field, remarked that these observations provide insight into Neptune’s dynamic atmosphere and suggest the occurrence of significant weather changes.