Researchers using a telescope on Hawaii in 2018 were able to determine that Uranus smells with an atmosphere rich in rotten egg smelling hydrogen sulfide; now another observatory on Hawaii combined with satellite data has confirmed that the mysterious planet also squirts x-rays.
Using technology made possible with a telescope on Hawaii’s Big Island, scientists have been able to identify the smelly gas there, setting the stage for other interesting discoveries in our Universe and beyond. Prior to this point, the composition of Uranus’ atmosphere has never been unambiguously identified. It was widely assumed to be composed primarily of either ammonia or hydrogen sulfide (H2S) ice. In a paper published in April 2018 in Nature Astronomy, scientists describe how they confirmed the hydrogen sulfide in the atmosphere there.
“If an unfortunate human were ever to descend through Uranus’ clouds, they would be met with very unpleasant and odiferous conditions,” study lead author Patrick Irwin, of Oxford University in England, said in a statement. “Suffocation and exposure in the negative 200 degrees Celsius (minus 328 degrees Fahrenheit) atmosphere, made of mostly hydrogen, helium, and methane, would take its toll long before the smell.”
Irwin and his colleagues studied Uranus’ air using the Near-Infrared Integral Field Spectrometer (NIFS), an instrument on the 26-foot (8 meters) Gemini North telescope in Hawaii. The Gemini North telescope is located near the peak of Mauna Kea on Hawaii; at nearly 14,000 feet, the telescope usually has a cloud and light-pollution-free view of space. NIFS scanned sunlight reflected from the atmosphere just above Uranus’ cloud tops and spotted the signature of hydrogen sulfide.
This week, in a new report published in the Journal of Geophysical Research, scientists have determined that Uranus is also emitting x-rays. In this new study, researchers used Chandra satellite observations taken in Uranus in 2002 and then again in 2017. They saw a clear detection of X-rays from the first observation, just analyzed recently, and a possible flare of X-rays in those obtained fifteen years later. Scientists were able to superimpose an optical image from the Keck-I Telescope, captured in another study in 2004, with the observations nearly at the same orientations as the satellite imagery, to help visualize what is happening. The Keck-I Telescope is located near the Gemini North telescope on Mauna Kea too.
NASA’s Chandra X-ray Observatory is a telescope specially designed to detect X-ray emission from very hot regions of the Universe such as exploded stars, clusters of galaxies, and matter around black holes. Because X-rays are absorbed by Earth’s atmosphere, Chandra must orbit above it, up to an altitude of 86,500 miles in space. The Smithsonian’s Astrophysical Observatory in Cambridge, Massachusetts , hosts the Chandra X-ray Center which operates the satellite, processes the data, and distributes it to scientists around the world for analysis.
Scientists aren’t completely sure why Uranus is squirting X-Rays. One possibility is the sun is responsible. Astronomers have observed that both Jupiter and Saturn scatter X-ray light given off by the Sun, similar to how Earth’s atmosphere scatters the Sun’s light. While the authors of the new Uranus study initially expected that most of the X-rays detected would also be from scattering, there are some hints that at least one other source of X-rays is present. If further observations confirm this, it could have intriguing implications for understanding Uranus. Another possibility is that the rings of Uranus are producing X-rays themselves, which is the case for Saturn’s rings. Uranus is surrounded by charged particles such as electrons and protons in its nearby space environment. 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.