Astronomers at NASA’s Chandra X-ray Observatory have detected X-rays from the planet Uranus for the first time.
Researchers used observations from the ice giant from 2002 and 2017 to detect the radiation as part of a new study published Tuesday in the Journal of Geophysical Research.
On a study and on further analysis, they saw clear X-ray detection from the first observation and possible X-ray burst from that 15 years later.
The scientists believe that the sun may be the driving force that causes Uranus to emit the X-rays.
Astronomers have previously observed that both Jupiter and Saturn scatter X-rays from the sun.
Although the authors of the study say they believe the X-rays detected are also from “scattering,” another source of X-rays is also likely.
Like Saturn, they say, the rings of Uranus could produce the X-rays themselves or even the planet’s aurora – a phenomenon that occurs when high-energy particles interact with the atmosphere.
“Uranus is surrounded by charged particles such as electrons and protons in its near space environment,” the Chandra X-ray Observatory wrote in a release. “When these energetic particles collide with the rings, they can cause the rings to glow in X-rays.”
X-rays are emitted in Earth’s auroras, and Jupiter also has auroras, although X-rays from auroras on Jupiter come from two sources.
However, a nearly identical NASA release notes that researchers remain uncertain about the cause of the auroras on Uranus.
The agency wrote that the unusual orientations of the axis of rotation and the magnetic field can cause the planet’s auroras to be “ unusually complex and variable. ”
Uranus’s axis of rotation is almost parallel to its orbit around the sun – unlike the axes of other planets in the solar system – and while Uranus is tilted on its side, its magnetic field is tiled to a different degree.
“Determining the sources of Uranus’ X-rays could help astronomers better understand how more exotic objects in space, such as growing black holes and neutron stars, emit X-rays,” NASA wrote.
Uranus is the seventh planet from the sun in the solar system. It has two sets of rings around its equator. Its diameter is four times that of the Earth.
Since Voyager 2 was the only spacecraft to ever fly past Uranus, astronomers rely on telescopes like Chandra to learn about the cold planet made up almost entirely of hydrogen and helium.