Scientists have discovered that clouds on distant planets may be doing much more than blocking our view.
New research suggests these clouds can trap heat so effectively that they may melt the rocky surfaces of some planets, creating giant oceans of molten rock.
The discovery could change how astronomers understand the most common planets in our galaxy.
The planets in this study are called sub-Neptunes. They are larger than Earth but smaller than Neptune.
Even though they are the most common type of planet found in the Milky Way, scientists still do not know exactly what they are made of.
Some may be rocky planets surrounded by thick layers of hydrogen gas, while others may contain large amounts of water or other materials rich in carbon.
The powerful James Webb Space Telescope (JWST) has allowed astronomers to study the atmospheres of these distant worlds. However, the telescope can only observe the upper layers of a planet’s atmosphere.
It cannot directly see what lies beneath the clouds or deep inside the planet. This makes it difficult to understand what these worlds are really like.
A new study published in The Astrophysical Journal Letters shows that clouds are not simply hiding information from scientists. They may also be changing the planets themselves.
Using advanced computer models, researchers at Arizona State University studied how clouds behave on sub-Neptune planets. They found that clouds made from vaporized rocks and salts can form deep inside the atmosphere. These clouds act like a thick blanket, trapping heat that would normally escape into space.
As a result, the lower atmosphere becomes much hotter while the upper atmosphere becomes cooler. In some of the planets studied, temperatures near the boundary between the atmosphere and the rocky interior increased by more than 1,000 degrees Celsius.
For two planets, called GJ 1214 b and TOI-1231 b, the extra heat was enough to melt the rocky surface beneath the atmosphere. Instead of solid rock, these planets may have enormous oceans of molten magma.
This finding is important because magma oceans can interact with the atmosphere. Just as volcanoes on Earth release gases, molten rock on these distant planets can also release chemicals into the air above.
The study found that gases such as oxygen, silicon hydride, and silicon monoxide are released more easily from the molten rock. At the same time, gases including methane, water vapor, and ammonia are absorbed into the magma instead of remaining in the atmosphere.
This means the atmosphere that JWST observes may not accurately represent what the whole planet is made of. Instead, the chemical signals seen by the telescope may have already been changed by the hidden magma ocean below.
The discovery makes studying sub-Neptunes more challenging, but it also gives astronomers a better understanding of how these planets work. Instead of treating clouds as something that simply blocks observations, scientists now see them as an important part of a planet’s evolution.
Clouds may influence how these planets cool over billions of years, how large they become, and even how their interiors develop. Since some sub-Neptunes are being studied as possible places that could support life under the right conditions, understanding how clouds affect their hidden interiors will help scientists build a more accurate picture of these mysterious worlds.
The new research brings astronomers one step closer to answering a long-standing question: what are the galaxy’s most common planets really made of?
Source: Arizona State University.
