A new experiment suggests that this exotic precipitation forms at even lower pressures and temperatures than previously thought and could influence the unusual magnetic fields of Neptune and Uranus.
An international team of researchers led by researchers from the Department of Energy’s SLAC National Accelerator Laboratory gained new insights into the formation of diamonds on icy planets such as Neptune and Uranus. Scientists believe that, following their formation, these diamonds would slowly sink deeper into the planetary interior in response to gravitational forces, resulting in a ‘rain’ of precious stones from higher layers.
The results, published today in Nature Astronomy, suggest that this “diamond rain” forms at even lower pressures and temperatures than previously thought and provide clues into the origin of the complex magnetic fields of Neptune and Uranus.
“‘Diamond rain’ on icy planets presents us with an intriguing puzzle to solve,” said SLAC scientist Mungo Frost, who led the research. “It provides an internal source of heating and transports carbon deeper into the planet, which could have a significant impact on their properties and composition. It might kick off movements within the conductive ices found on these planets, influencing the generation of their magnetic fields.”
Longer timescales
In earlier work conducted at SLAC’s Linac Coherent Light Source (LCLS) X-ray free-electron laser (XFEL), scientists were able to observe “diamond rain” as it formed in high-pressure conditions, confirming the possibility of diamond formation on icy planets, which are primarily composed of water, ammonia, and hydrocarbons. They later discovered that the presence of oxygen makes diamond formation more likely, allowing diamonds to form and grow at a wider range of conditions and throughout more planets.
Previously, the high pressures and temperatures were generated by shock compressing the hydrocarbons with high power lasers, which only allows the conditions to be maintained for a few nanoseconds. In this new experiment, conducted at the European X-ray free-electron laser in Germany, the team studied the reaction over much longer timescales than other experiments using a different approach.
Read more on the SLAC website