What Is Life? Carl Zimmer

Kate Adamala is a chemist at the University of Minnesota. In her Protobiology Lab, she is trying to build a synthetic cell from scratch.

Donato Giovannelli is an assistant professor at the University of Naples “Federico II.” He travels to acid lakes and other extreme environments that are the closest thing today to what Earth was like when life began.

All the life we know is the same: carbon-based, with DNA for genes. (Okay, except for RNA viruses.) But Steven Benner says it doesn’t have to be that way. Benner is a Distinguished Fellow at the Foundation for Applied Molecular Evolution.

Jeremy England is a physicist at MIT. He has developed an influential theory of life as a way for matter to dissipate energy.

We don’t know how life got its start. But as more evidence emerges, explains astrobiologist Caleb Scharf, only a few theories are emerging as leading contenders. Scharf is the director of the Columbia Astrobiology Center at Columbia University.

H. James Cleaves is a professor at the Earth-Life Science Institute in Tokyo and co-author of A Brief History of Creation: Science and the Search for the Origin of Life.