Huge chunks of ice like the ice cream smoothie made from a mixture of ammonia and water could be responsible for anomalies in the atmospheres of planets like Neptune and Uranus.
This icy object is likely to be highly effective at sending ammonia deep into the atmospheres of icy giant planets, causing the gas to be hidden under opaque clouds, according to research led by scientists. Tristan Guillot presented at the Europlanet Science Congress (EPSC) 2021.
Recently, distant observations at infrared and radio wavelengths indicate that, compared with other giant planets in the Solar System, Uranus and Neptune lack ammonia in their atmospheres. This is notable because the two planets are rich in other compounds, such as methane, in the primordial cloud from which the planets form.
Tristan Guillot is a researcher at CNRS, the Laboratoire Lagrange research institute in Nice, France. He turned to a recent discovery of Jupiter for a solution.
Observations by the Juno spacecraft at Jupiter indicate that ammonia-water hail can form rapidly during storms because ammonia has the ability to liquefy water ice crystals, even at temperatures very low about -90 degrees Celsius.
Models show that Jupiter’s ice balls can grow to weigh 1kg or more, bigger than the largest hailstones on Earth. As they plunge below, they very efficiently transport ammonia to the planet’s deep atmosphere, beyond the reach of existing instruments on Earth.
To accurately determine the depth to which icy bodies carry ammonia and water deep into the atmospheres of planets in space, humanity needs to wait for an orbiter with more modern instruments available.
“Neptune and Uranus are an important link between giant planets, like Jupiter and Saturn, and the icy giant exoplanets we’re discovering in the galaxy. the need for it,” said scientist Tristan Guillot.