Heartbeat at the Edge of the Solar System

The spellbinding tale of a hidden track on NASA's Golden Record, the recording sent into space in 1977 to explain life on Earth to aliens, and a profound exploration of what it means to be human in this vast universe.

More than 16 billion miles from Earth, beyond the edge of the Solar System, a message is waiting to be heard. It is a secret engraved on a phonographic record, preserved in gold and copper, and bolted to the side of a spacecraft. It is the brainwaves and heartbeat of Ann Druyan, a young writer who spent an hour reflecting on the entire history of life on Earth while hooked up to an EEG and EKG recorder.

She thought about human imagination and invention, but also war, poverty, and tyranny. What shaped that hour more than anything, though, was the fact that Ann had just fallen in love. And not just with anyone, but with the astronomer Carl Sagan, whom she would later marry. How, Ann wondered, could she convey how profoundly love shapes, and reshapes, a human life?

Recorded on a summer’s day in 1977, and launched into space a few months later, Druyan’s life signs make up a track on the famous Golden Record: a compilation of Earth recordings assembled on the slim chance that aliens might someday find it. That track is a message of love and loss. It is also the answer to a question asked by scientists and philosophers for centuries: what does it mean to be human?

Through the little-known history of physiological recording, from pulse-reading to cardiographs to EEGs, and the men and women who gave us new ways of knowing one another’s hearts and minds: the first to detect lovesickness through the gentle placement of fingertips to a wrist; the first to register the brainwaves of a dream; the first to record a fetal heartbeat, this book tackles the question of what it means to be human by telling Ann’s story, but also the stories of scientists, inventors, thinkers, and dreamers who asked it before her.

The result is a stunning work of narrative nonfiction, which weaves together science, history, and art, to chart our search for connection across time and space. It reveals that, underneath it all, we are a species defined by our hearts.