For a long time, probably as long as we have been gazing up at the night sky, people have been asking ourselves: Are we alone? Is there life out there, anywhere else in the universe?

For modern Earthlings, our fascination with extraterrestrial life has focussed on one place in particular:

Mars.

The planet today is a forbidding, arid place. But billions of years ago, Mars may have had a gigantic ocean. It was, like Earth, just the kind of place you’d think life could get started.

Earlier this month, in the journal Science, NASA astrobiologist Dr. Jen Eigenbrode and her team published a stunning discovery. The Curiosity rover on Mars had found rocks that contain organic molecules — the building blocks of life.

On this episode of Orbital Path, Dr. Michelle Thaller sits down with Eigenbrode to understand what this discovery really says about the possibility of life on Mars.

This episode of Orbital Path was produced by David Schulman.

Our editor is Andrea Mustain. Production oversight by John Barth and Genevieve Sponsler.

Support for Orbital Path is provided by the Alfred P. Sloan Foundation, enhancing public understanding of science, technology, and economic performance.

Image credit: NASA