Follow us on Google News (click on ☆)
Scientists have long thought these planets were primarily composed of frozen water, but recent discoveries indicate their makeup could be more complex. Data collected by the Voyager 2 probe and Earth-based observations show these planets also possess significant amounts of oxygen, carbon, and hydrogen. This diverse composition raises questions about the formation of these giants.
Uranus shines amidst its luminous rings in this image from the James Webb Space Telescope.
Credit: NASA, ESA, CSA, STScI
Current models, based on measured physical properties, describe a hydrogen and helium envelope, an underlying layer of compressed ice water and ammonia, and a central rocky core.
However, new analyses suggest these models might be incomplete. These icy giants would have formed by the accumulation of planetesimals, similar to the current comets in the Kuiper belt, a region filled with icy bodies beyond Neptune.
Uri Malamud, the lead researcher of the study and planetary scientist at the Israel Institute of Technology, questions the possibility of forming a giant like Uranus and Neptune from construction blocks poor in ice. To explore this idea, the team constructed hundreds of thousands of models of these planets' interiors.
These models take into account various chemical compounds, including iron, water, and methane, and seek to determine which model best matches the observed characteristics.
The results show that models with a significant proportion of methane are the most conforming. Methane could appear in solid blocks or, given the pressure, in a paste-like state, forming a thick layer between the hydrogen-helium envelope and the ice water.
These discoveries could enlighten our understanding of these still mysterious planets, although verifying their methane richness poses a challenge. Malamud emphasizes that this could be a goal for one of the proposed missions by NASA and other space agencies aimed at exploring Uranus.