Neptune Storm Disappearing as Hubble Keeps Watch

Neptune's massive storm, large enough to span from Boston to Portugal on Earth, appears to be disappearing while scientists using NASA's Hubble Space Telescope continue to keep watch, according to Fox News.

The Voyager 2 spacecraft first spotted dark storms swirling in Neptune's atmosphere during a flyby in 1989, Fox News wrote. A new study on Neptune's storms was published last week in The Astronomical Journal.

NASA said in a statement that Neptune's storms appear to last only a few years, unlike Jupiter's Giant Red Spot, which has been visible for at least 200 years. NASA reported, though, that this is the first time scientists have been able to photograph a Neptune storm while it appears to be dying.

"The particles themselves are still highly reflective; they are just slightly darker than the particles in the surrounding atmosphere," Joshua Tollefson from the University of California, Berkeley, said in the NASA statement.

The space agency wrote that the dark spot material may be hydrogen sulfide, with the smell of rotten eggs, but it gives astronomers an opportunity to study Neptune's deep winds, which cannot be directly measured.

"We have no evidence of how these vortices are formed or how fast they rotate," Agustín Sánchez-Lavega, of the University of the Basque Country in Spain, said in the NASA statement. "It is most likely that they arise from instability in the sheared eastward and westward winds."

NASA wrote that like Jupiter's famous Great Red Spot, though, the storm appears to swirl in an anti-cyclonic direction and is dredging up material from deep inside the ice giant planet's atmosphere.

Michael H. Wong, of the University of California at Berkeley and the lead author of the new Neptune study, referred to previous work done by Ray LeBeau, now at St. Louis University, and Tim Dowling’s team at the University of Louisville, in comments about the planet's failing storm, NASA noted.

"It looks like we're capturing the demise of this dark vortex, and it's different from what well-known studies led us to expect," Wong said in the NASA statement. "(LeBeau and Dowling's) dynamical simulations said that anticyclones under Neptune's wind shear would probably drift toward the equator. We thought that once the vortex got too close to the equator, it would break up and perhaps create a spectacular outburst of cloud activity."

Neptune's dark spot has apparently just faded away rather than going out with a bang, NASA wrote.

• New Horizons Probe Passes Neptune On Its Way to Pluto
• Pluto Planet Status Debated as NASA Scientists Suggest New Definition