Uranus is an ice giant 19 times farther from the sun than the Earth. It is one of the darkest planets in the solar system. The planet’s atmosphere consists mainly of hydrogen, helium and methane. Astronomers have spotted unexplained mega storms ripping apart its atmospheric cover. It has become so stormy that, for the first time ever, even amateur astronomers were able to see details in Uranus’ blue-green atmosphere.
Weather on Uranus is incredibly active now
A team of scientists led by Imke de Pater of the University of California, Berkeley detected eight giant storms on the planet’s northern hemisphere. The storms were spotted on August 5 and 6 while observing Uranus with the Keck Observatory. De Pater said at a meeting of the American Astronomical Society’s Division of Planetary Sciences that the weather on Uranus had become “incredibly active.”
Since it is so distant, scientists were unable to see details on the planet’s surface until adaptive optics on Keck Observatory telescopes revealed the features. Uranus doesn’t have an internal source of heat. So, scientists initially believed that its atmospheric activity was driven by sunlight, which is currently very weak in the northern hemisphere. That’s why astronomers were surprised to see such intense activity.
This kind of activity would have been expected in 2007
One of those eight storms was the brightest storm ever observed on Uranus at 2.2 microns, a wavelength that monitors clouds below the tropopause. This storm alone accounted for more than 30% of the total light reflected by the rest of the planet at 2.2 microns. Co-investigator Heidi Hammel said this kind of activity would have been possible in 2007, when the planet’s once-in-42-years equinox occurred. During the equinox, the sun shined directly on the equator.
But why these incredible storms are occurring now be “beyond anybody’s guess,” said Hammel. De Pater and her team have been studying Uranus for well over a decade. Larry Sromovsky, an astronomer at the University of Wisconsin, said that the storm might be due to a vortex in the deeper atmosphere. An expanded team of scientists used the Hubble Space Telescope to image the entire Uranus on Oct.14. Hubble revealed several storms extending over a distance of 5,760 miles.