Ripples on the Cosmic Ocean: An Environmental History of Our Place in the Solar System

by Dagomar Degroot

The untold story of how environmental change throughout the cosmos shaped five hundred years of human civilization.

Our solar system is a dynamic arena where asteroids careen off course and solar winds hurl charged particles across billions of miles of space. Yet we seldom consider how these events, so immense in scale, influence our fragile blue planet: Earth.

In Ripples on the Cosmic Ocean, Dagomar Degroot traces the surprising threads linking human endeavor to the rest of the solar system. He reveals how variability in planetary environments has shaped geopolitics, spurred scientific and cultural innovation, and encouraged new ideas about the emergence and fate of life. Martian dust storms altered the trajectory of the Cold War and inspired fantastical stories about alien civilizations. Comet impacts on Jupiter led to the first planetary defense strategy. And volcanic eruptions spewed sulfuric acid into Venus’s atmosphere, exposing the existential risks of climate change at home.

As we stand on the brink of a new era of space settlement, cosmic environments are becoming increasingly vulnerable to human activity. They may also hold the key to slowing the destruction of environments on Earth. Ripples on the Cosmic Ocean urges us to develop an interplanetary environmentalism across a vast mosaic of entangled worlds and to consider the profound connections that bind us to the cosmos and each other.

Genres: Science, Nonfiction, Nature, Astronomy, History, Space, Environment

416 pages, Hardcover

First published October 28, 2025

About the author

Dagomar Degroot is an environmental historian, author, and professor at Georgetown University. He was the 2024–2025 Baruch S. Blumberg Chair in Astrobiology, Exploration, and Scientific Innovation at the Library of Congress.

Reviews

[John Kerl · Rating 5 out of 5]

If you read one popular-science book this year, this is the one.

I grew up on Carl Sagan's _Cosmos_ and have read a lot of popular science ever since. I go to a science center with the kids and I find a reassuring familiarity with things I see there, things which match what I already know.

Not so with Degroot's book. Thoroughly well researched, inquisitive, original, poetic -- Degroot digs deeper and reveals paths less well-trodden, but ever important. I particularly enjoyed how the author connects cutting-edge speculations in various decades and centuries to prevailing concerns of the time. For example, detailed Mars maps in an era when colonial European powers prized detailed maps of territories they were conquering. Or why the movie _Armageddon_ came out the year it did. I learned about things I'd never heard about before, such as TLPs on the Moon. (Still unexplained!)

Strong recommend.

[Judith · Rating 5 out of 5]

Very clear and readable Though I have read much about astronomy, I learned much from this book, including some historical developments (that I lived through when I was younger post 1950) and about current thoughts of astronomers re: the odds of asteroids (and comets) crashing into the earth and the effects thereof (including the dinosaur extinction). I highly recommend this book

[Riccardo Tedesco · Rating 3 out of 5]

Definitely an interesting book, but not exactly what I was expecting. I was hoping for more focus on contemporary theories and ideas, while a big part of the book leans into the history behind them.

The structure works well overall, but at times I found it a bit heavy to get through. Still, an interesting and worthwhile read.

[Andrea · Rating 4 out of 5]

An interesting trip through the intersections of astronomy with human politics and culture with lots of scientific information woven in.