Those white areas aren’t clouds; they’re aurorae—”northern lights”—around the poles of Uranus, captured by the Hubble Space Telescope in 2012 and 2014. (The image of Uranus itself was acquired by the Voyager 2 spacecraft in January 1986.)
“The auroras on Jupiter and Saturn are well-studied, but not much is known about the auroras of the giant ice planet Uranus. In 2011, the NASA/ESA Hubble Space Telescope became the first Earth-based telescope to snap an image of the auroras on Uranus. In 2012 and 2014 a team led by an astronomer from Paris Observatory took a second look at the auroras using the ultraviolet capabilities of the Space Telescope Imaging Spectrograph (STIS) installed on Hubble.”
Aurorae on Uranus are driven by the same process that creates them around Earth’s polar regions: charged particles from the Sun get caught in the planet’s magnetic field and are focused toward the poles, where they make ions in the upper atmosphere release energy—in these observations in ultraviolet wavelengths. Also, since Uranus orbits the Sun “tilted sideways” its polar regions are near the plane of its orbit.
Read the rest of this article from NASA here: Hubble Spots Auroras on Uranus
Voyager 2 may have been the second of NASA’s famous twin exploration spacecraft but it launched first, on August 20, 1977. Eight and a half years later it became the first (and last) spacecraft to visit Uranus, at 31,500 miles across the third largest planet in the Solar System. Voyager 2 made its closest pass by Uranus 31 years ago, giving us our best views to this day of the enormous ice giant and its moons.
The distant ice giant Uranus may not have been visited by a spacecraft since Voyager 2’s “Grand Tour” flyby in 1986 but the data gathered then is still being used today to make new discoveries. Most recently, researchers think they have found evidence of two previously unknown moons around Uranus, potentially bringing the planet’s count up to 29.
People of past civilizations had their own ideas of what the stars in the night sky are… distant campfires, lights shining through holes in a vast blanket covering the Earth, deceased ancestors, countless and constantly-traveling gods… whether or not they really believed these stories or if they were just tales to inspire poets and provide entertainment on dark nights is hard to tell. But one thing is for certain: we now know what those points of light really are, thanks to the past several centuries of hard work by astronomers, scientists, and engineers, and although that may make ancient tales about the stars obsolete it certainly doesn’t reduce the inherent wonder and beauty of the night sky – if anything, it has increased it many times over.
Recently French cartoonist Boulet illustrated his own lifelong fascination with space in a webcomic published on his Bouletcorp.com site. In a Dante-esque fashion he takes the figure of French singer Georges Brassens on a trip across the solar system, showing him why science and rational thought have not chased away fascination and beauty along with “the old gods”, as Brassens sang in a 1964 song (which I was not familiar with.) “Eureka” was not a death sentence for wonder!
It’s a really beautiful comic, with brilliant timing and subtle animations to highlight keep points along the way. Don’t scroll too fast.
HT to Laurie C. for the link.
Out in the depths of our solar system, about 1.8 billion miles away from the Sun somewhere between the planets Saturn and far-flung Neptune, orbits the oddball ice giant Uranus – a frigid, thinly-ringed world tipped almost completely on its side and shrouded in both mystery and pale blue-green clouds. Aside from the occasional bright storm clouds spotted along the planet’s mid-latitudes and the even rarer darker blue storms, Uranus’ atmosphere has proven to be remarkably featureless… especially around its high southern latitudes.
Now, astronomer Erich Karkoschka from the University of Arizona has used imagery from Voyager 2’s 1986 visit to Uranus to bring out some visible features in the planet’s skies by using pattern recognition software to map out even the most subtle differences, and then boosting the contrast to make them more apparent. What he’s found are atmospheric anomalies that hint at curious structures in the planet’s dense core far beneath.
Watch a very cool animation below showing the new details Karkoschka has teased out of 29-year-old Voyager 2 data: