Is Cosmic Life Mostly Underground?
In a public lecture that I gave last night at the planetarium of the Frost Science Museum in Miami, Florida, hosted graciously by Senator René Garcia and his Deputy Chief of Staff Lauren Pardo, I emphasized that settling on nearby rocks that are less hospitable for life than Earth, like the Moon or Mars, is not the best way to secure the long-term survival of humanity. Instead, it would make more sense to launch our technological ambassadors to space in the form of AI-guided robots, or perhaps even humans, on artificial space platforms that were designed specifically for long-term survival. Nature is under no obligation to make us happy and living in the natural environment of the Moon or Mars will likely be a nightmare to all humans involved.
But there is another survival mode. If surface conditions on Earth will severely deteriorate in our future as a result of a giant asteroid impact, a nuclear war or climate change, humanity might choose to go underground.
Nature may have made a similar choice billions of years ago. Most of the real estate of rocky material lies far from stars. It may well be the case that most life forms in the Universe thrive underground. Astrobiologists associate the habitable zone around stars with the region where the surface temperature of a rocky planet allows for liquid water and the chemistry of life-as-we-know-it (as reviewed in my textbook “Life in the Cosmos”). However, frozen worlds far from any star may host subsurface life under a thick surface layer of ice. In 2018, I co-authored a paper (accessible here) with my former postdoc, Manasvi Lingam, which demonstrated that energy supply from radioactive materials can sustain life in liquid water underground.
Some tech billionaires are already constructing luxurious bunkers to survive a societal collapse they helped create (as reported here). If we ever land a spaceship on the scorched surface a post-world-war exoplanet, we should search for billionaire bunkers with survivors.
But closer to home, most life forms on present-day Mars may have indeed survived underground. It would indeed be a good idea to send helicopters with cameras into lava tubes on Mars in search for life forms which were protected there from the harsh surface conditions of extreme temperature variations between day and night, lack of liquid water and bombardment by cosmic-rays. These helicopters could also search for prehistoric paintings on the walls of natural Martian caves. If intelligent life emerged on Mars a few billion years ago, then there might even be billionaire bunkers there before Elon Musk’s arrival.
***
Following clarifications from The Astrophysical Journal regarding editorial practices pertaining to three papers on interstellar objects, I would like to apologize to the Associate Editor, Maria Womack, who apparently followed the proper editorial procedures which my co-authors and I had misinterpreted. Here’s hoping for a constructive and purely positive relationship with all editorial staff in the future.
ABOUT THE AUTHOR
Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024.
Professional website:
https://lweb.cfa.harvard.edu/~loeb/
Social media:
https://avi-loeb.medium.com/
https://www.youtube.com/@ProfessorAviLoeb
https://open.spotify.com/show/1zhndXkvSY2b8FdjspFpCd
https://x.com/ProfAviLoeb
