Astronomers have confirmed, for the first time, X-rays coming from the ice giant Uranus, NASA announced Wednesday. The results from the Chandra X-ray Observatory could help answer questions from the mysterious neighbor that has only been visited once by an Earth spacecraft.
Researchers used Chandra observations of Uranus in 2002, which showed a clear detection of X-rays that were only recently analyzed, and observations in 2017 which appeared to show a possible flare of X-rays.
In the composite image below, "The main graphic shows a Chandra X-ray image of Uranus from 2002 (in pink) superimposed on an optical image from the Keck-I Telescope obtained in a separate study in 2004," NASA said.
The sun is the most likely reason Uranus is emitting X-rays, according to NASA, similar to how there is X-ray scatter from Jupiter and Saturn. But NASA added there are hints that Uranus could have another source for its X-rays, which would be key to understanding the seventh planet.
One possibility, NASA said, is that Uranus' two sets of rings are sending out the X-rays, just as Saturn's rings do.
"Uranus is surrounded by charged particles such as electrons and protons in its nearby space environment," NASA said. "If these energetic particles collide with the rings, they could cause the rings to glow in X-rays. Another possibility is that at least some of the X-rays come from auroras on Uranus, a phenomenon that has previously been observed on this planet at other wavelengths."
Just like our planet and others, Uranus has auroras. But while those on Earth are caused by high-energy particles hitting he atmosphere, NASA said scientists aren't sure what causes the auroras on Uranus. The new observations could help answer that question.
Observations from Chandra and the Hubble Space Telescope are vital to better understanding Uranus. Only one spacecraft, Voyager 2, has ever visited the ice giant. It passed by in 1986.