Imagine a hypothetical reality in which life on Earth had been offered to us at birth as an optional package deal and we could have accepted or declined it. Given all I know today about terrestrial politics, I would have not taken the offer. However, if the package deal had included the option of transfer to another planet where there is no politics, I would have been thrilled to accept it.
Today, a few Harvard deans congratulated me for the fact that my recent podcast interview attracted more listeners than simultaneous interviews of U.S. Presidential candidates during an election season. One of the deans suggested that I use this popularity to get into politics. I clarified that my conclusion is exactly the opposite, namely that science is more inspiring than politics.
Given that terrestrial politics will not go away, is there a way to get away from it? Travel packages between planets are not hypothetical, but real opportunities that might have been offered to lucky organisms on Mars and Earth for billions of years.
Panspermia involves the transport of life from a parent planet to an adopting planet. It could have materialized for microbes or viruses in the interiors of rocks that were chipped off the surface of their birth planet. The promise of these trips depends on the ability of microbes to survive inside rocks for millions to billions of years. A research team from the University of Tokyo announced recently that a two-billion years-old rock had been home to living microbes on Earth. The team used an original technique to confirm that the microbes were native to the rock sample, by staining the DNA of the microbial cells and using infrared spectroscopy to look at the proteins in the microbes and surrounding clay. We now know that colonies of microbes live in rocks far beneath the surface of Earth for billions of years.
If microbes can feed for so long on rock, perhaps they can survive on journeys between planets. Analysis of future data sets with artificial intelligence (AI) can be used to check whether the Last Universal Common Ancestor (LUCA) born 4.2 billion years ago, was delivered to Earth from outer space. The latest AI analysis suggests that RNA viruses likely preceded the evolution history of cellular organisms on Earth.
The Nobel laureate Francis Crick suggested together with Leslie Orgel in a 1973 paper the concept of Directed Panspermia, that “organisms were deliberately transmitted to the earth by intelligent beings on another planet.” A much more likely possibility is that the transfer occurred in a natural rock. In 2018, I wrote a paper with my postdocs, Idan Ginsburg and Manasvi Lingam, that quantified the expected number of interstellar rocks that could have delivered life to Earth. We now know, based on the discovery of meter-size interstellar meteors like IM1 and IM2 over the past decade that there were a billion interstellar objects like them which collided with Earth over its 4.6-billion-years history. Even if most rocks followed an interstellar journey that lasted billions of years, as found in my recent paper with my student Shokhruz Kahkarov, some of them might have had shorter trips with better prospects for survival through freezing temperatures and bombardment by cosmic-rays.
In summer 2025, I hope to lead an expedition that will aim to collect large pieces of the interstellar meteor, IM1, from the bottom of the Pacific Ocean. Our research team will use a Remotely Operated Vehicle with a video feed. If we recover large pieces of IM1, I would be very curious to examine them for tiny interstellar astronauts in the form of viruses or microbes from outside the Solar system.
In a WORLD.MINDS forum today led by the brilliant Rolf Dobelli, the Princeton University sociologist Matt Salganik explained how difficult it is to forecast with AI the actions of humans based on data about their past life. I asked him: “Clearly, life is defined by the interaction of individuals with their environments. Is the unpredictability a result of the environments having unknown components or the individuals evolving over time?” Matt leaned towards the environmental possibility.
Altering the environment of a host planet could be a life-changing experience, literally speaking. In the case of Mars, which cooled before Earth and may have given rise to LUCA, the transport of life to Earth was a life-preserving experience. Since Mars lost its atmosphere and liquid water about 3.5 billion years ago, it is possible that it still hosts relics of microbial life in frozen ice or in the interior of some of its rocks. This is a reasonable expectation given the evidence for living microbes in the 2-billion-year-old terrestrial rocks.
NASA’s Perseverance Rover recovered Martian rocks that are billions of years old. The proposed Mars Sample Return mission of NASA and ESA aims to use robotic systems and a Mars ascent rocket to collect and send samples of Martian rocks, soils and atmosphere to Earth for detailed chemical and physical analysis. Finding life in Martian ices or rocks with the same genetic makeup of terrestrial life, would suggest common ancestry and possible panspermia between Mars and Earth.
As exciting as the discovery of microbes might be, I would be much more excited about the possibility that we might find technological debris from aliens among the vast population of interstellar rocks. The latter encounter could educate us about new alien technologies and inspire us to reproduce them. The discovery of new `Oumuamua-like interstellar objects will be facilitated by the Rubin Observatory in 2025. But even before that, the U.S. Congress will hold a hearing next month about Unidentified Anomalous Phenomena. Scientific curiosity is the only theme that brings Republicans and Democrats together. Even during an election season, terrestrial politics is of secondary importance when dealing with extraterrestrials.
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.
