Think of the most expansive question a popular science book could address. It might be: What are the parameters of life? If you envision life as a contained space, the center would be filled with organisms like humans, giraffes, carnivorous plants, and toenail fungus—very different in nature, yet all descendants of one common ancestor. At the outer edges of it would lie the extremophiles discovered by scientists in the ‘80s and ‘90s: bacteria that thrive in super hot hydrothermal vents, or subsist purely on caffeine (as microbiologists have recently uncovered). Everything outside of the space is what David Toomey explores in his ingenious new book Weird Life; it’s all in the realm of possibility—of shadow biospheres on our planet, extraterrestrial life, and even extra-universal life.

There are a few disadvantages to focusing a book on what life could be, rather than decidedly is. One is that unadventurous scientists—and readers—will dismiss what you and your subjects are doing altogether. When I ask Toomey what he thinks is the biggest misunderstanding about his subject, what he calls weird life, he replies: “the mere fact that there might be such a thing.” He explains that many microbiologists think that even if there were a form of life that does not come from our last universal common ancestor, it would look a lot like life that does. That our chemical pathways are so seemingly perfectly adaptable to our environment, and the chemicals present in it, is a good reason for thinking this. But it might also be a narrow way of thinking. “There’s another line of thought that says there are other chemical pathways and we simply haven’t discovered them,” Toomey says.

This line of thinking has fascinated scientists working in vastly different domains—from microbiology to theoretical physics. “My big challenge was finding out where to look and pulling together a narrative thread that wasn’t obvious or preexisting,” Toomey explains, describing another obstacle he faced in writing about a largely incipient field. “There are no weird life studies, no journal of weird life.”

As we discover in Toomey’s book, however, there are plenty of potential weird life candidates. Some are on Earth. For example, an oceanographer has tried to determine whether there are bacteria in Mono Lake, a closed basin in the California desert that has an extremely high concentration of arsenic, that could not only withstand but also incorporate the poison into its molecules. Unfortunately, a review board shot down her research. But after reading Toomey’s considered portrayal of her work, we can appreciate that it allowed the idea of weird life on Earth to enter public discourse in the scientific community.

A weird life species could end up being the aliens in our solar system we have been searching for. Toomey painstakingly details several scientists’ ideas about life that thrives on exotic sources—silicon and methane, among others—on Mars and Jupiter’s moons, and in Venus’ atmosphere. One of the most interesting research projects in the book belongs to Lou Allamandola, a senior researcher at NASA who is making a comet from scratch in order to study its properties, a discovery that might determine whether the environment could support life. “You couldn’t help but envy what he got to do every day,” Toomey remarks, “to come in and try to create an artificial comet in a chamber that simulated deep space and see what happened.” 

Creating an artificial comet is not the most esoteric project covered in Toomey’s book, though. That description belongs to the research of the theoretical physicists who are tackling the most seemingly distant possibility for weird life—in parallel universes. At this point, as he tries to explain models of particle physics and string theory, Toomey is on the brink of losing even the most patient, open-minded reader. 

But he soon puts his subject back into perspective. He reminds you that in many ways, the study of weird life may only matter in terms of getting us to celebrate the natural life that we do know exists. “During an age in which many are increasingly disconnected from the natural world, an appreciation of that world from a fresh perspective is no small matter,” he writes. Even if you put the book down still skeptical about the likelihood of weird life, Toomey will at least reignite your interest in biology and astronomy, and possibly spark daydreams about cloud aliens on Venus. For him, that means success.