Decades of psychological research explains why.

There’s nothing revolutionary about being a middleman.

While we like to imagine little green men, it’s far more likely that life on other planets will be microbial. Planetary scientist Nathalie Cabrol takes us inside the search for microbes on Mars, a hunt which counterintuitively leads us to the remote lakes of the Andes mountains. This extreme environment — with its thin atmosphere and scorched land — approximates the surface of Mars about 3.5 billion years ago.

Four approaches that work.