In the coming decades, new rovers will roam the sands of Mars. An orbiter will sample the seas of Jupiter’s moon Europa. A drone will grace the skies of Saturn’s moon Titan. Mission planners dream of equipping these mechanical scouts with instruments capable of scouring the unknown environments for signs of life, but the technology required to do so is deceptively complex.
Explorers seeking alien life must first grapple with questions of fundamental biology. What does it mean to be alive? What traits must all organisms share — even those that might inhabit methane lakes or ice-locked oceans? The burgeoning field of astrobiology seeks answers in the form of “biosignatures”— surefire signs of life that a simple experiment could identify, such as DNA or proteins.
Steven Benner, founder of the Foundation for Applied Molecular Evolution at the University of Florida and leader of a group of researchers, showed that the four-molecule genetic code that describes all known life on Earth isn’t the only group of molecules that could support evolution.
“You set these grand challenges to make a new Darwinian system,” says Benner. “That drags scientists kicking and screaming across uncharted terrain.”Learn more about How NASA Is Using Synthetic DNA in Its Search for Alien Life.