Q&A WITH A PLANETARY RESEARCH SCIENTIST

Research into whether Venus had liquid oceans in its past is giving more insight into how Earth has so far avoided a runaway greenhouse effect

- Melissa Brobby

Considering how molten Venus's surface was in its past, how might it have formed a liquid water ocean?

When we think about the evolution of planets, we envision them beginning their life in a hot and molten state, and as they evolve through time, they emit radiation into space and cool down. So, the key question is whether or not by cooling down, Venus was able to condense the water it had in its atmosphere onto the surface. If the water did not condense, then it is unlikely that liquid water oceans would have formed. The current thinking is liquid water oceans might have formed from steam at an early point during Venus's evolution, the steam condensing on the planet's surface and turning from a vapour to a liquid. This is probably what also happened on Earth in its past.

What methods were used to find this out?