In 1950, the physicist Enrico Fermi is said to have asked “Where are they?” — that is, in a universe teeming with galaxies, and in a galaxy teeming with stars, why have we not yet seen clear evidence of extraterrestrial life? Are we alone, or are there other worlds out there harboring life? Is our universe itself special in some way that makes it conducive to life?

We have asked three scientists to discuss some of the latest research and scholarship regarding the place of life, including human life, in the universe. Sara Seager (below) describes the search for Earth-like planets orbiting distant stars and explains what led her to join the hunt. Marcelo Gleiser shows why the findings of physics should help ease our sense of cosmic angst. And Luke A. Barnes explains what it means to say that the universe appears “fine-tuned” for life.

Publication of this special section was made possible through the support of a grant from the John Templeton Foundation; the opinions expressed herein are those of the authors and do not necessarily reflect the views of the John Templeton Foundation.