Published: Sun, February 10, 2019
Research | By Raquel Erickson

Nasa spots mysterious storm clouds gathering over Uranus and Neptune

Nasa spots mysterious storm clouds gathering over Uranus and Neptune

"Thankfully we're not too far away from having an answer, as the James Webb Space Telescope will be able to diagnose the temperatures and chemistry responsible for these reflectivity changes that Hubble has been monitoring".

Recently, the Outer Planet Atmospheres Legacy (OPAL) program has released new images that highlight an evolving atmospheric event on both ice giants, namely an extended white cap over Uranus' north pole and a new dark vortex on Neptune.

The space agency also spotted a new storm brewing on Neptune.

NASA and the Space Telescope Science Institute (STScI) announced the discovery of the storm on Thursday.

Appearing during the planet's southern summer, the feature is the fourth and latest mysterious dark vortex captured by Hubble since 1993.

According to NASA, the storm is monstrous.

Uranus is now deep into its summer season, and that shows in the giant, white cloud covering the planet's north pole, which now points toward the sun. Two of these storms were observed by the Voyager 2 probe during its flyby of the system in 1989.

It's thought this caused a cloud of smelly methane gas to form around the planet's north pole which shines brightly when the sun's light catches it.

This latest vortex was photographed by Hubble in September 2018 during a scan of Neptune's northern hemisphere. The dark patch that is a 6,800-mile-wide storm is visible on Neptune, accompanied by some whiteish companion clouds, as NASA called them. "This polar hood may have formed by seasonal changes in atmospheric flow".

With the planet now reaching the middle of its summer and the polar cap storm seeming to become more prominent, experts think the changes may result from this seasonal shift which influences movements in the atmosphere.

In this case, it is still unclear just why these storms form, but much like the Great Red Spot on Jupiter, they swirl in an anticyclonic direction.

Similar to Earth, Neptune and Uranus have seasons that change atmospheric conditions.

Scientists believe this feature is a result of Uranus' unique rotation.

The agency added: "Just as meteorologists can not predict the weather on Earth by studying a few snapshots, astronomers can not track atmospheric trends on solar system planets without regularly repeated observations". Because of this extreme tilt, during the planet's summer the Sun shines nearly directly onto the north pole and never sets. It's now mid-summer at Uranus' north pole, resulting in the protracted white cap. But as time progressed, a reflective band-whitish against Uranus' blue hues-began to appear encircling the north pole.

NASA also points out the smaller white blob just at the edge of the blue region, which it says is likely a thick cloud of methane-ice. "It is a mystery how bands like these are confined to such narrow widths, because Uranus and Neptune have very broad westward-blowing wind jets".

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