So we are getting close to the possibility of detecting (with some kind of specrometry) an exoplanet with an atmosphere with a chemical composition that is far from thermodynamical equilibrium.
It would be a thrilling feeling to know that there, maybe 20 or 100 light-years away, is such a planet, hosting at least microbial or algal life.
I'm not convinced we know enough to do this. A planet in the right temperature with a high-oxygen atmosphere might just be low-carbon and high pH, such that the entire surface is oxidized and glassy and the liquid water carries a pH in the 12s.
What's great is, we're about to get a whole lot more data with which to do astrochemistry.
It would be a thrilling feeling to know that there, maybe 20 or 100 light-years away, is such a planet, hosting at least microbial or algal life.