Hydrogen cyanide is one of the most reactive and toxic molecules we know, but astrobiologists view it with almost alchemical qualities for the origin of life.
Another epic photo of Earth from space was taken on July 19 of Earth from Saturn by Cassini, and released on July 22. From Mercury, the MESSENGER spacecraft also portrayed Earth as a small dot.
Some basic ideas about physics and astronomy remain so mysterious, and their explanations so flexible, they may lead some to question whether they should be called "hard sciences."
The search for extra-terrestrial intelligence is like a detective story without a body. All those new planets, but no signal—at least not one that most scientists will accept.