Astrobiologist David Grinspoon explains the significance of finding phosphine molecules on Venus. Grinspoon is a Planetary Science Institute senior scientist and author of ["Venus Revealed: A New Look Below The Clouds Of Our Mysteriious Twin Planet."](https://www.amazon.com/Venus-Revealed-Clouds-Mysteriious-Planet/dp/0201406551) [Strange chemical in clouds of Venus defies explanation. Could it be a sign of life?](https://www.space.com/venus-clouds-possible-life-chemical-discovery.html) Credit: Space.com / produced & edited by [Steve Spaleta](http://www.twitter.com/stevespaleta)