Hubble Space Telescope Discovered Neptune's Massive Storm Disappearance

On February 20, 2018, reports highlighted the Hubble Space Telescope’s observations tracking the decline and disappearance of a massive dark storm on the planet Neptune. The storm, first identified by the telescope in 2015, initially spanned a width comparable to the Atlantic Ocean.

Over a two-year period, a series of Hubble images captured the dark vortex shrinking and fading away. According to reports at the time, this marked the first time scientists were able to observe a storm on Neptune from its beginning to its extinction. While Jupiter’s Great Red Spot has remained visible for at least two centuries, massive storms on Neptune are known to endure for only a few years.

Researchers noted that the behavior of the anticyclonic storm defied previous simulations. Computer models had predicted that the vortex would drift toward the equator, where it was expected to trigger a large display of cloud activity. Instead, the storm began fading away before reaching the equator. A scientist from the University of the Basque Country in Spain stated that there is no direct evidence of how these vortices form or how fast they rotate, though they likely arise from instabilities in the planet’s eastward and westward winds.

Only the Hubble Space Telescope and the Voyager spacecraft have successfully observed Neptune’s vortices. Hubble’s ability to use ultraviolet light allows it to probe the outer planets of the solar system. A paper detailing the findings of an international team of researchers was published online in the Astronomical Journal on February 15, 2018.