Mushballs inside Uranus and Neptune may solve an atmospheric mystery

By Leah Crane

Uranus and Neptune may be hiding slushy hailstones called mushballs deep inside them. These huge clumps of water and ammonia may explain why there is so little ammonia higher up in the ice giants’ atmospheres.

Compared to the other giant planets, Uranus and Neptune seem to contain surprisingly little ammonia – based on measurements of other compounds, all of the giant planets in our solar system ought to have about the same amount. Either these two formed in some sort …