Uranus and Neptune may be hoarding ammonia ‘mushballs’ deep within their atmospheres

Neptune and Uranus could be storing ammonia deep in their atmospheres as ‘mushballs’ – hailstones made of ammonia and water. The planets appear to lack ammonia compared to other planets, and Tristan Guillot from the Laboratoire Lagrange in Nice might have found out why in his latest study, which searched for the answer on Jupiter.

“The Juno spacecraft has shown that on Jupiter ammonia is present in abundance, but generally much deeper than expected – thanks to the formation of mushballs,” says Guillot.

These mushballs form in storms at high altitude, trapping ammonia inside. Weighing up to a kilo, they fall through the atmosphere carrying the ammonia with them. On Uranus and Neptune, the portion of the atmosphere that forms mushballs is much higher.

“Thus, ammonia is probably simply hidden in the deep atmospheres of these planets, beyond the reach of presentday instruments,” says Guillot. lagrange.oca.eu/en/welcome-lagrange

IMAGES: NASA/CALTECH