New dark spot on Neptune

Hubble telescope discovers gigantic hurricane and bright accompanying cloud

The new spot on Neptune, in visible light (left) and in the blue spectrum. © NASA / ESA, MH Wong and J. Tollefson (UC Berkeley)
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Storm spot on the gas giant: In the atmosphere of Neptune, a new, gigantic cyclone has formed. It is so big that it appears as a dark spot in Hubble telescope images despite its enormous distance. The cyclone tears up methane gas so much that it freezes and forms an accompanying bright cloud spot, as astronomers report.

Neptune is a planet of storms: At speeds of up to 2, 100 kilometers per hour, the winds are racing around the ice giant - faster than anywhere else in the solar system. Some form elongated ligaments, others are concentrated in huge swirls, which can be recognized as dark or bright spots in its bluish gas envelope.

It started with a bright cloud spot

Already in July 2015, astronomers discovered a new bright spot on Neptune - typical of clouds of frozen methane crystals in the upper atmosphere of the ice giant. Frequently, such clouds form as a concomitant for large cyclones, the gas from deeper layers in the air and let it freeze there.

"The dark storm swirls soar in the atmosphere like huge lenticular gas beds, " explains Mike Wong of the University of California at Berkeley. "The clouds are more like the orographic clouds on Earth, which often hang like pancake-shaped cotton balls over the earthly mountain peaks." Such clouds arise when air rises on mountain slopes and condenses on cooling.

Close-up of the new storm vortex: Even the high-resolution Hubble telescope only sees it blurred. © NASA / ESA, MH Wong and J. Tollefson (UC Berkeley)

New cyclone

After discovering the new cloud spot, astronomers already suspected that it also hides a dark storm vortex. However, these dark spots only become visible when one observes the planet in the light of the blue wave spectrum and thus virtually fades out the bright, covering clouds. The only telescope that can do this with sufficient resolution is the Hubble Space Telescope. display

And indeed, as it turns out, a new dark storm vortex has actually formed on Neptune. Because astronomers have been watching this vortex in both September 2015 and May 2016, they expect it will probably last a while. It is the first new cyclone on Neptune in this century.

Engine of the storms still unclear

This is a valuable opportunity for the planetary scientists. For the existence of storm giants on a planet so far from the sun is so far R tsel. Because Neptune gets barely a thousandth of the Earth's solar energy, this might not be enough to power the raging winds.

From the observation of the new storm vortex and its development, astronomers hope to gain more insight into the processes in the Neptune atmosphere and possible impulses of the giant storms.

(NASA / Goddard Space Flight Center, Jun 24, 2016 - NPO)