SOME planets around other stars could have life hidden under layers of weird high-pressure ice, in oceans far deeper than Earth’s.
Extreme pressures can create unusual forms of ice rarely seen on Earth. To investigate what this means for other planets, Lena Noack at the Royal Observatory of Belgium and her colleagues modelled rocky worlds with very deep oceans.
They found that on a planet with Earth’s mass, a layer of high-pressure ice can form in oceans about 170 kilometres deep – more than 15 times the depth of the lowest point in Earth’s oceans.
Given ample heat from the planet’s interior, water can remain liquid under the ice long enough for life to take hold. The model works for planets up to 10 Earth masses (Icarus, doi.org/bjxk).
Such modelling is speculative, but could apply to worlds within our solar system. Noack notes that Jupiter’s moon Ganymede has a lot of water as a proportion of its mass, far more than Earth does. Depending on heat from the interior, it’s possible Ganymede could have high-pressure ice covering a liquid layer, and Noack plans to apply her models there.
This article appeared in print under the headline “Alien life could lurk under deep ice”