Preliminary results from a study discussed at the European Geosciences Union General Assembly suggest Venus-like planets, characterized by dense CO₂ atmospheres and lethal surface conditions, may be twice as common in the galaxy as Earth-like planets. Presented by Sean Jordan from ETH Zurich, the research indicates that as rocky planets cool from a molten state, they tend to develop thick CO₂ atmospheres rather than those conducive to liquid water.
The study, while still unreviewed and based on models rather than direct observations, posits that the conditions for forming Venus-like atmospheres may be more readily achievable than those for Earth-like atmospheres. However, confirming the presence of such atmospheres on exoplanets remains a challenge due to uncertainties around atmospheric retention influenced by host stars’ radiation.
Jordan emphasizes that Venus, our closest neighbor, is critically underexplored, with no recent dedicated missions to study its atmospheric composition. This lack of exploration hampers our understanding of atmospheric processes that might be common on Venus-like exoplanets.
Looking ahead, Jordan predicts that understanding the prevalence of Venus-like atmospheres will take decades, especially with proposed NASA missions to Venus facing potential cancellation. The study highlights a shift in perspective regarding rocky planets, suggesting that Earth-like conditions may not be the norm, with Venus-type atmospheres possibly being the more common outcome of planetary formation.
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