In an era where news from beyond Earth frequently captures headlines, readers accustomed to following extraterrestrial developments might recall recent reports of potential life on distant planets or a Mars rover’s discovery of compelling signs of ancient microbial activity. A year prior, public attention was also briefly fixed on the perceived threat of an asteroid impact. However, these cosmic curiosities often recede, overshadowed by more immediate earthly concerns such as ongoing conflicts or the escalating climate crisis. The abstract allure of distant microbes, for instance, while momentarily intriguing, raises a fundamental question: what is the tangible relevance of these astronomical findings to our lives here on Earth?

Dagomar Degroot, a climate historian, posits in his book, “Ripples on the Cosmic Ocean: How the solar system shaped human history – and may help save our planet,” that directing our gaze outward toward celestial phenomena has, in fact, exerted a significant influence on the course of human history.

Degroot, described as an interdisciplinary historian and currently an environmental historian at Georgetown University, approaches scientific progress from a broad perspective. His research draws from the archives of both renowned and lesser-known scientists. This extensive work underpins his central argument: that understanding our existence on Earth is fundamentally enhanced by observing the broader cosmos. As Degroot eloquently states, “We cannot pretend the ocean does not exist. It is not only because its waves will come whether we look for them or not; it is also because we can only understand our island by looking out toward the ocean.”

Throughout human history, the presence of neighboring planets in the night sky has significantly broadened our understanding. Without these celestial bodies, our comprehension of Earth’s climate, including past ice ages and projected global warming trends, would be considerably diminished. Furthermore, we would face a heightened vulnerability to existential threats, ranging from nuclear proliferation to catastrophic asteroid events. The historical development of our worldview, particularly the challenging religious frameworks surrounding the heliocentric model, would likely have evolved very differently.

Celestial Observations and Earthly Concerns

Degroot illustrates the profound impact a single celestial body can have. Consider Venus, a planet characterized by an inhospitable environment: scorching surface temperatures exceeding 460°C, driven by blazingly hot volcanoes that emit sulfur dioxide.

This understanding of Venus’s current state is a relatively recent development. Early astronomical observations were hindered by the planet’s dense atmosphere, a factor now understood to obscure its features. By the 19th century, however, most astronomers observed that Venus possessed a cloud cover.

This atmospheric veil gave rise to speculative notions about potential life forms existing beneath it. Such imaginative theories were instrumental in fostering the burgeoning concept of cosmic pluralism, which proposed that Earth was not unique as a habitat for life.

As observational technologies advanced and revealed the true, forbidding nature of Venus, a more pressing concern emerged: the possibility that Venus’s fate might foreshadow Earth’s future.

The realization that Venus’s extreme heat stemmed from a runaway greenhouse effect naturally led to questions about whether a similar phenomenon could occur on Earth. Prominent scientists who dedicated substantial research to Venus and its atmosphere, including astronomer Carl Sagan and climate scientist James Hansen, played a crucial role in sounding the alarm about the potential for Earth’s climate change.

Degroot’s book presents numerous examples of such connections. The dust storms that render Mars inhospitable prompted scientists to consider analogous scenarios that could be triggered by nuclear warfare. Similarly, the observable fragmentation of comet Shoemaker-Levy 9 as it traversed Jupiter’s atmosphere in 1994 served as a stark reminder to remain vigilant for similar cosmic threats to Earth.

Engaging with Scientific Narratives

“Ripples on the Cosmic Ocean” also offers engaging narratives drawn from the history of scientific thought, often featuring eccentric personalities. One such figure is Immanuel Velikovsky, a psychoanalyst of Russian-American origin who appears to particularly capture Degroot’s interest. Velikovsky, drawing upon ancient mythology, made a number of surprisingly prescient predictions regarding Venus, alongside many less accurate ones. From the 1950s through the 1970s, his theories presented a notable challenge to the scientific establishment.

Navigating the Future of Space Exploration

While Degroot effectively argues for the importance of observing space, his proposals for managing future observations and space exploration appear less certain. This is particularly relevant given the current era of unprecedented space exploration, largely driven by commercially funded ventures such as Elon Musk’s SpaceX and Jeff Bezos’s Blue Origin.

Degroot suggests the possibility of pursuing a different approach to space, one that avoids exploitation for the benefit of a select few. Historically, the study of the solar system has often been motivated by such desires, with colonial elites seeking knowledge to further imperial ambitions. Instead, Degroot advocates for enriching life on Earth, envisioning a future where humanity “build[s] in the water to support our home, for everyone’s collective benefit.”

One illustrative example he cites is space-based solar power, which could involve deploying solar panels on the Moon to beam energy back to Earth. However, given the nascent stage of current experimental efforts in this area, the argument lacks substantial persuasive power.

Despite this, Degroot clearly conveys that humanity faces a decisive choice regarding its engagement with the solar system. “Humanity’s past was influenced, in part, by ripples on the cosmic ocean,” he writes. “More will come, no matter what we do. Now we are gaining the capacity to make our own waves. Our future may depend on how we make them.”

Recommended Reading on the Solar System:

Pale Blue Dot: A Vision of the Human Future in Space by Carl Sagan. Inspired by an Earth image captured by NASA’s Voyager spacecraft, Sagan’s book contemplates what the solar system can teach us about our cosmic significance.
The War of the Worlds by H. G. Wells. Mentioned in Degroot’s main review, this classic highlights the historical impact of a convincing radio adaptation that led listeners to believe Earth was genuinely under Martian invasion.
A City On Mars by Kelly Weinersmith and Zach Weinersmith. The Weinersmiths, a cartoonist and biologist writing duo, present a scientifically precise and artistically illustrated account of the challenges associated with off-planet living, emphasizing the harsh realities of life on Mars.