How long do you think an organism can live? A hundred years? A thousand? What if I told you that there are creatures that can “breathe” metals, survive in pure acid, and stay alive for hundreds of thousands of years? I’m not talking about creatures from another planet (or maybe I am). The intraterrestrials, as the scientist named them Karen Lloyd, are organisms so strange and alien that they make us completely reconsider what it means to be alive.
You don't have to travel into outer space to find them: they are right here, on Earth, but in places so extreme and inaccessible that until a few decades ago we didn't even know of their existence (and even now we know very little about it).
A hidden and surprising world
While much of the public remains fascinated by the possibility of life beyond earth, there are already tiny organisms on our planet that are as alien as anything we have imagined. These microbes are found in places once considered inhospitable to life: inside volcanoes, beneath the Earth's crust on the seafloor, or in Arctic permafrost. They're not just surviving in these harsh environments, they're doing so in ways that defy fundamental biological principles we thought were set in stone.
In his new book (it comes out tomorrow, but I was privileged to check it out) “Intraterrestrials: Discovering the Strangest Life on Earth" Karen Lloyd, a microbial biochemist at the University of Southern California, takes us on a fascinating journey into the world of these extraordinary organisms. I confess that I really like this approach: instead of looking for alien life in space, Lloyd has dedicated her career to the study of life forms that, despite being terrestrial, are extremely “alien” compared to what we know. And what do these intraterrestrials look like?
Phone (under) house: creatures that defy the rules
The most surprising thing about these microbes is how evolutionarily distant they are from anything we see on a daily basis. Think of the differences between a cat and a snail; well, that evolutionary distance pales into insignificance when we compare these animals to intraterrestrials.
“There are things we could never have imagined: that life on Earth was as diverse as we now know it to be. They are simply so different evolutionarily from anything we see with our eyes.”
We already knew that there are life forms that do not require oxygen (think of the bacteria in our intestines). But the idea of entire ecosystems that never require oxygen or the influence of plant matter, which can exist only thanks to chemical reactions coming from inside the Earth… this is new. And that's what we're learning with these organisms.
Intraterrestrials: Fundamental Questions Still Unanswered
The biggest questions about these organisms still remain very basic. Who are they all? What are they doing? What do they eat? What role do they play on Earth? How do they interact with metals? What role have they played in the evolution of our planet over time?
Answering even a few of these questions is complicated, and I don't want to spoil future Italian versions of the book. And then, regardless, it's complicated because we can't simply observe them as we would a tree. It requires specialized technology and innovative methods.
Why look for aliens in space?
Interestingly, while we obsessively search for signs of alien life in space, the most “alien” organisms we have ever encountered are right here, beneath our feet. According to research by we were talking to you a while ago, 86,6% of astrobiologists are convinced that aliens exist, at least in a basic form. But perhaps we should pay more attention to what we have already discovered about our planet.
Lloyd recently spoke in an interview about his latest expedition to New Zealand, where he explored a subduction zone (where two tectonic plates overlap). This process creates volcanoes, but it also generates a sort of “alchemical mix” that allows these underground communities to establish themselves. His enthusiasm is contagious as he describes how much fun it is to do this work, “even on a human level.”
Life on other worlds?
Studying intraterrestrials could help us better understand the possibilities for life on other planets. If organisms can live in such extreme environments on Earth, perhaps similar life forms could exist in places like Europe (moon of Jupiter) or Enceladus (Saturn's moon), where scientists have identified oceans beneath the icy surface.
On Europa, specifically, scientists they identified some underground pools of salt water that could demonstrate the presence of life. NASA has even planned the mission Europa Clipper to investigate this possibility.
Intraterrestrials, a window to the future
I was particularly struck by the sense of hope and possibility that Dr. Lloyd conveys through her research. As she said:
“I hope people feel a sense of hope and possibility. There’s a whole world beneath our feet. We’re just beginning to explore it.”
There is still so much to discover, right beneath our feet. A whole world of living things that challenge our understanding of life itself, reminding us how little we still know about our planet and, perhaps, the universe.
