Scientists who have been studying Neptune and Uranus believe they may have found a solution to a mystery surrounding the atmospheres of the planets. A new study from a scientist named Tristan Guillot suggests that mushballs could be responsible for carrying ammonia deep into the atmospheres of Neptune and Uranus. Mushballs are large hailstones made of a slushy mixture of ammonia and water.
The new theory could be an answer to why observations in infrared and radio wavelengths of Uranus and Neptune have shown that both planets lack ammonia in their atmosphere compared to other gas giant planets. Mushballs could be extremely effective at carrying ammonia deeper into the planet’s atmosphere, making it hard to detect beneath the dense clouds of the atmosphere.
The lack of ammonia in the atmospheres of the two planets has stumped scientists because the planets are rich in other compounds, including methane, typically found in the atmosphere of gas giant planets. Scientists believed that either Uranus and Neptune formed under special conditions using material that was poor in ammonia or another process is occurring on the planets.
Guillot used a discovery on Jupiter as a potential answer to the mystery of where the ammonia is on Neptune and Uranus. The Juno spacecraft in orbit around Jupiter found abundant amounts of ammonia, but the ammonia is much deeper in the atmosphere than expected, thanks to mushballs. Juno’s observations showed that ammonia-water hailstones form rapidly during storms on Jupiter because ammonia can liquefy water ice crystals even at very low temperatures.
On Jupiter, those ammonia-water hailstones are highly efficient at transporting ammonia very deep into the planet’s atmosphere, locking it away under the clouds. That process on Jupiter leads Guillot to believe mushballs are responsible for the lack of ammonia detected in the atmospheres of Uranus and Neptune. However, to fully understand the process, the researcher says more study is needed.