It's OK to pursue speculative ideas because we don't want to be too cozy and safe and assume that we know everything about life in the universe. However, we have to be rigorous and careful and honest and logical and scientifically meticulous when we speculate.

In environments that are energy-rich but liquid-poor, like near the surface of Titan, natural selection may favor organisms that use their metabolic heat to melt their own watering holes.

It's quite possible there's as much lightning on Venus as on Earth.

David Grinspoon Quotes