David Kaplan explores the best ways to search for alien life on distant planets.
Searching for signs of life on faraway planets, astrobiologists must decide which telltale biosignature gases to target.
Did the minerals on our planet arise in a predictable fashion, or did they result from chance events? The answers could eventually help scientists identify planets likely to harbor life.
Evidence from Southwestern deserts suggests that oxygen-breathing organisms arose on land rather than in the seas.