What does it mean to be “alive”? Astrobiologists such as Nathalie Cabrol must contend with the lack of a concrete answer as they explore the universe looking for something out there that can properly be called life. As director of the Carl Sagan Center for the Study of Life in the Universe at the SETI Institute, which focuses on the search for extraterrestrial intelligence (SETI), Cabrol avoids imposing strict limitations on where and how life has, could or will evolve. After all, we still don’t quite understand how life emerged on our own world.
In her new book The Secret Life of the Universe, Cabrol presents both a comprehensive guide to how life could have evolved across our solar system and a review of life’s own journey on Earth, using historical, scientific and even spiritual lenses. Cabrol grounds our quest to find and define “life” in the natural balance, the give and take, between the biological and its environment. In doing so, she highlights how unnatural humanity’s recent relationship with Earth truly is, emphasizing a need to restore balance with our home planet as we continue to explore other worlds.
Scientific American spoke with Cabrol about the field of astrobiology’s rapid growth, the ways we can prepare for the day we do find extraterrestrial life and the interconnectedness between the living and nonliving, between ourselves and the universe.
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[An edited transcript of the interview follows.]
Your book opens by calling the present the golden age of astrobiology, even though we have yet to actually find extraterrestrial life. What makes this the golden age?
The question of whether we are alone in the universe—this is not something new. What is really new is that our generation has the means now to [use] the technology and [explore] these worlds. We are discovering incredible things. We are discovering so many habitable worlds. We still have to figure out if “habitable” means “inhabited”—that’s a different question. But [there is] so much potential. It’s so very important to understand that first, our understanding of the universe depends on the technology we have at any given time..., and the more we look at it, the more we transform our questions [and our] perspective. We’re at the time where we are looking at what astronomy, astrobiology, environmental sciences, climate sciences, exoplanets [and] planetary exploration are telling us, and we’re starting to [make a] universal Venn diagram of what things are and where they overlap. And I think we’re starting to see something pop out of this.
How can artificial intelligence help in this search?
AI is a tool, and it has downsides, as we know, but ... it has this potential of seeing patterns that the human mind might not see. That allows us to listen to space now much faster [and] deal with so many more data. It’s really an incredible tool not only for the present data but also [to] look back at the archives and see if we missed something in the past. Although AI is built by humans, it has ... this ability to create new connections that were not necessarily put in there by humans. [AI] is our first and best chance to really be confronted with an alien language. Although it is designed by humans, it tends to take a life of its own sometimes. Our studies of how AI evolves are almost like trying to figure out what an alien language is going to look like. It’s certainly a way for us to be confronted with something different and something that we do not have control over..., something we still have to understand. This is our first training ground.
Can we ever be fully prepared for first contact?
Nothing can prepare us for the real deal, for one good, very scientific reason: the way we think, the way we look at our own world and the universe, is really very much dictated by our own evolution on this planet. And you can imagine that an extraterrestrial civilization is going to be just the same. They are going to be designed to respond to their environment, and they will perceive the world and the universe around them as a function of that. So we have no clue if they are even thinking like us, if they’re interested by the same things as us. The only thing we can be sure of is that if they are advanced enough and intelligent enough, they will already have picked up on the universal laws. When the Pioneers [missions 10 and 11] and the Voyager mission left [Earth], all of them had [diagrams] of some kind on them ... [showing] astronomical features such as pulsars, planetary alignment and things like that to try to convey a universal message and not something that comes from our own culture and evolution on this planet.
You address the dichotomy of spirituality and science in the book in a way that leaves the door open for these classically separated realms to merge. Can you talk more about that?
Especially in astrobiology, one of these universal things [is the] co-evolution of life and environment. This has to be universal because when life emerges, it changes everything. We’ve seen that on Earth: [life] changes the atmosphere, and then the environment changes life, and then life changes the environment. [There is a] back and forth all the time, and how does this translate in spiritual writings? In oneness—you see this in all these [religious texts], whether you are a Buddhist, you are Muslim or you are a Christian, or [in] Indigenous cosmogonies. This is probably the first foundation of spirituality: understanding the environment you are in and maintaining its balance, something that we have completely lost today. And so we are out of spiritual alignment with our planet, and we can measure that. So, you know, this opposition of science and spirituality is something I never understood. There is no way you can [put the two in opposition]. There is a quote I like that may relate more or less to what we’re saying right now: “We are not human beings having spiritual experiences. We are spiritual beings having a human experience.”
For me, one of the greatest achievements of astrobiology is not only this outward look that we have on the immensity [of] space but also this insider’s look of our place here on our own planet—and the place we should have not only as the apex species right now but our responsibility in this biosphere and our role to protect it.
What major questions are the field of astrobiology wrestling with these days?
I think that one of the great debates of astrobiology today is, is something alive? We don’t know. Is something intelligent? We don’t know. Is something conscious? We don’t know. If we’re starting to build organic robots and they are starting to act independently in a way that looks like they are living, then where is this frontier between living and nonliving? We search for life elsewhere starting with the premise that there is life and there is environment, right? It’s not a simple equation with two unknowns once life emerges on the planet. And I say emerge, I don’t say appear.... Emerge says more about a transition or a change. When [life] does [emerge], there is not such a thing anymore as environment and life. You have a living planet and you have a co-evolution, and from that point on, there is no separation.
You discuss the need for new frameworks for thinking about the search for and meaning of life as we amass more and more information. Can you give an example of one such framework?
Thermodynamics! [Life is] the best way to beat entropy. I love this because it gives us a handle on how to search for life in a universal way; [it’s] not something that is led by biochemistries. If the living process transforms its way of interacting with particles and energy and information, then we are onto something.
If you could change one scene in a movie about extraterrestrial life, what would it be?
I adore the movie Contact for good reasons: it’s both using [the] reality of the search we have right now and our limitations, and ultimately you see the alien taking a form that [Jodie Foster’s character Ellie] can recognize because they know otherwise that they are going to be scary. It’s a friendly approach. I always go back to that scene of when she’s floating in the spacecraft and all of a sudden she touches ... this ripple, kind of like there is a transparent sheet between her and space. That was [Contact novel author] Carl [Sagan]’s vision of it, and I found it beautiful. The more I advance in the field, the more I research, I would go one step further than this vision. Instead of putting sort of a separation [between us and the universe], I would love to see this being in fact a fusion, like there is no separation. When you move your hand in the universe, everything is moving with you.