Excitement and interest is building to probe Uranus, an icy, smelly, distant planet which appears to be squirting out X-Rays. This year’s decadal survey by the National Academies of Sciences, Engineering, and Medicine is suggesting that NASA’s main planetary science project of the next decade should be probing Uranus, using an orbiter and probe mission to unlock the planet’s mysteries. The survey report, prepared every 10 years, represents the culmination of six panels, hundreds of white papers, invited speakers, outreach to advisory groups and professional society conferences, and work with mission-design teams to understand what the priorities of the science industry should be in the coming years.
“This report sets out an ambitious but practicable vision for advancing the frontiers of planetary science, astrobiology, and planetary defense in the next decade,” said Robin Canup, assistant vice president of the Planetary Sciences Directorate at the Southwest Research Institute, and co-chair of the National Academies’ steering committee for the decadal survey. “This recommended portfolio of missions, high-priority research activities, and technology development will produce transformative advances in human knowledge and understanding about the origin and evolution of the solar system, and of life and the habitability of other bodies beyond Earth.”
In terms of priority flagship mission, the survey concluded that the Uranus Orbiter and Probe (UOP) should be the highest priority large mission. The UOP would conduct a multiyear orbital tour to transform knowledge of ice giants in general, and the Uranian system in particular, through flybys and the delivery of an atmospheric probe.
Little is known about Uranus. Last year, scientists determined Uranus smells and squirts X-rays. 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; an additional observatory on Hawaii combined with satellite data confirmed that the mysterious planet also squirts x-rays.
“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 at the time of the smelly discovery. “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.”
In 2021, scientists discovered the presence of x-rays coming from the planet. 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 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.
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.
Last year, scientists also determined there were slush balls moving about the atmosphere on Uranus. The slushballs, also referred to as mushballs, could contain ammonia in addition to water, and be carried about in the Uranus atmosphere through thunderstorms.
A non-NASA affiliated Twitter account, @ExploreIGO (Ice Giant Missions), asked the internet earlier this week what such a probe mission to Uranus be called. Hundreds of people replied, adding to the excitement of this possible planetary mission. While some suggested “Uranal Probe”, “Wandering Finger”, “Operation Butt Plug”, “F.A.R.T.” for Far Advanced Recognizance Team, and “Probbie McProbeface”, some offered more serious names such as “Caelus”, Roman God of the skies, “SE7EN”, referring to the it being the 7th planet from the sun and has an unusual axial tilt, and “Ten’nosei” which is Uranus in Japanese which translates to “Heaven / Sky King”.