Comment #418143 by astroprof

...and environments where liquid ANYTHING is possible are relatively rare

That's just not true, at least in our solar system. Venus is shrouded in highly concentrated liquid sulfuric acid clouds; some have speculated that its clouds could host airborne extraterrestrials. Mars may very well have liquid water in the subsurface and almost certainly did in the past. Saturn, Jupiter, Neptune, Uranus, all have clouds made of liquids. Europa probably has a liquid subsurface ocean. Titan has organic lakes with spectral signatures of liquid methane and ethane and the same liquid in clouds. Titan may also have an ammonia-water liquid in the subsurface much like Europa. Enceladus has water vapor spewing out of the south pole. Io spews liquid and gas sulfur. Indeed, most of the planets and a not insignificant number of their satellites have liquids. Assuming we have a rather ordinary stellar system, the same probably holds true for extra-solar systems.