A dark vortex on Neptune revealed a never-before-seen phenomenon

A dark vortex on Neptune revealed a never-before-seen phenomenon

Jupiter may have the most famous storm in the solar system, but that doesn’t mean it leaves the most interesting behind. Neptune has just given scientists a new mystery.

Although storm vortices are not unusual for the distant ice giant, astrophysicists have spotted the first instance of a storm turning back to the polar region after migrating toward the equator. Scientists still aren’t sure how or why the course changed, but finding out may tell us more about Neptune’s atmospheric dynamics.

Today, Hubble is the only instrument capable of continuously observing distant Neptune. The telescope has tracked four other similar storms, called Dark Spots because of their darker hue than the surrounding atmosphere. In general, their behavior was quite similar: they appear at mid-latitudes, stay about two years, migrating toward the equator, and then disperse. Then, four to six years later, another one appears.

A dark vortex on Neptune revealed a never-before-seen phenomenon

But this fourth storm, observed by Hubble and dubbed NDS-2018, was the exception. “It suddenly just stopped and went back. It was amazing, we hadn’t seen anything like it before,” said planetologist Michael Wong of the University of California, Berkeley.

NDS-2018, as its name implies, was first discovered in 2018. By then, it had been growing for several years and was about 11,000 kilometers across.