NASA planetary scientist says Uranus upper atmosphere is likely cooler than Voyager 2 indicated

William Saunders is a planetary scientist at NASA Langley Research Center and Analytical Mechanics Associates who studies the upper atmospheres of Uranus and Neptune. In his PhD work he used dozens of Earth-based measurements and concluded that the Voyager 2 1986 results showing an extremely hot thermosphere were likely flawed and that Uranus’s upper atmosphere is likely cooler.

At Langley Saunders focuses on thermal structure and how energy is transported around ice giant atmospheres. The Voyager 2 flyby in 1986 showed Uranus to have an extremely hot thermosphere, which the source says cannot be explained by known sources of heating; Saunders’s analyses of Earth-based data led to revised temperature estimates for the upper stratosphere and lower thermosphere.

Saunders uses stellar occultations — observations of a distant star as a planet passes in front of it — to measure refraction of starlight through the atmosphere, infer density at various altitudes, and calculate temperature and pressure for detailed upper-atmosphere studies. His publications include 2023 and 2024 Planetary Science Journal papers on Uranus stellar occultations and a 2022 assessment of space-based occultation feasibility, as well as a 2021 paper on gravity waves in Mars’s middle atmosphere.

Key Topics

Science, William Saunders, Uranus, Stellar Occultation, Thermosphere, Neptune