Massive Dark Storm on Neptune appears to have shed a fragment and changed direction

There's a storm raging on the surface of Neptune that is wider than the Atlantic Ocean. The storm responds in the northern hemisphere of the planet and was first spied by the Hubble Space Telescope in 2018. Observations made in 2019 showed that the storm was drifting southward towards the equator of the planet.

In August 2020, Hubble noticed that the storm was changing directions again, heading back to the north. Hubble has tracked similar dark spots on Neptune over the past three decades, but the current storm's behavior is something new. Hubble also spied a smaller dark spot in January 2020 that temporarily appeared near the larger storm.

Astronomers believe the smaller storm could be a piece of the giant storm that broke off, drifted away, and later disappeared. Researchers believe that the smaller dark fragment could be part of the dark spot's disruption process. That process has never been observed. Researchers note that while they have seen some other dark spots fading away and then seen they were gone, they have never seen anything disrupt despite it being predicted in computer simulations.

The massive storm is 4600 miles across and is the fourth dark spot Hubble has observed on Neptune since 1993. Another dark storm was discovered by Voyager 2 in 1989 when it flew by the planet on its way to interstellar space. However, before Hubble could be trained on Neptune to observe them, they disappeared.

Typically, the sort of storm on Neptune appears to form and then disappear over a couple of years. The current storm is been raging since September 2018. The dark storms are high-pressure systems that form at mid-latitudes and migrate toward the equator. Typically, as the storm moves towards the equator, the Coriolis effect weakens them and the storm disintegrates. The current storm never migrated to the equator and still rages.