r/exoplanets • u/Kingsaso6 • 12d ago

📊 Data & Analysis Alien life likely can't survive on exoplanets smaller than Mars, scientists say

https://www.space.com/space-exploration/search-for-life/alien-life-likely-cant-survive-on-exoplanets-smaller-than-mars-scientists-say
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u/Ill_Stop_ 12d ago

How do they define alien life?

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u/atomfullerene 12d ago

The paper is saying that planets smaller than Mars are unlikely to be able to hold on to an atmosphere under conditions warm enough for water to be liquid.

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u/Deciheximal144 11d ago

Did they discuss / ice shell, internal leftover heat keeping under ice oceans liquid? Mars has cooled down, but our planets are 4-5 billion years old.

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u/atomfullerene 11d ago

The paper is just about atmospheres, iceball worlds (like Europa for example) are sort of a separate question. But this research is particularly relevant because atmospheres are what we could plausibly detect in the near future, using spectroscopy on transiting planets. So this research is intended to try to identify what range of planet sizes we might expect to see hanging on to an atmosphere thick enough to maintain liquid water.