Neptune, the eighth planet from the sun and fourth-largest planet by diameter in our Solar System, has a dark vortex, according to NASA.
The U.S. space agency’s Hubble Space Telescope confirmed the existence of the vortex on June 23.
“Dark vortices coast through the atmosphere like huge, lens-shaped gaseous mountains,” research astronomer Mike Wong, with the University of California at Berkeley, said in a statement. Wong led a team that carried out research on Hubble’s results.
“And the companion clouds are similar to so-called organic clouds that appear as pancake-shaped features lingering over mountains on Earth,” Wong said. Similar features were seen during the Voyager 2 flyby of Neptune in 1989 and when the Hubble Space Telescope passed by in 1994.
The dark vortices on Neptune are “high-pressure systems” accompanied by “companion clouds.” The clouds are believed to be methane crystals formed when surrounding air is pushed up over the vortex, NASA said. The companion clouds were spotted first, leading researchers to the dark spot.
In July 2015, the bright clouds were detected again on Neptune, by amateur and professional astronomers.
Like Earth’s weather systems, the dark spots on Neptune constantly change in terms of size, stability, and shape. They, however, can last for years and the vortex spotted by Voyager 2 was estimated to be the size of Earth itself. “They also come and go on much shorter timescales compared to similar anticyclones seen on Jupiter; large storms on Jupiter evolve over decades,” says a news release on the Hubble telescope’s website.
The dark vortex that was recently recorded by Hubble is about the width of the continental United States.
The telescope obtained images on May 16 of the dark vortex, the first one observed in the 21st century.
Astronomers are hoping to “better understand how dark vortices originate, what controls their drifts and oscillations, how they interact with the environment, and how they eventually dissipate,” according to the Hubble news release.