Question of the week: Will astronomers ever find life elsewhere in the solar system?
My answer: I have been on public record since the 1980s that it is simply a matter of time before planetary astronomers discover the remains of life on another solar system body besides Earth. The reason why is that meteoritic bombardment of Earth has exported Earth’s microbes throughout the solar system. For example, astronomers calculated that meteoritic bombardment has delivered an average of 20,000 kilograms of Earth soil to every 100 square kilometers of the Moon’s surface.1 For Mars, the calculated delivery is 200 kilograms per 100 square kilometers. For the upper atmosphere of Venus, it is approximately 1,000 kilograms per 100 square kilometers. For all other solar system bodies, besides the Sun, the delivery rate is less than a kilogram per 100 square kilometers.
One ton of Earth soil contains about 100 quadrillion microbes. Given the 3.8-billion-year history of abundant microbial life on Earth, a lot of Earth’s life has been exported throughout the solar system. Given that Earth was bombarded much more heavily during the first billion years of life history than it is now, most of the life exported from Earth will be the first microbes that existed on Earth.
Back in 2007 and 2009 I wrote two articles, “Why We Need to Go Back to the Moon,”2 and “Where to Look for Earth’s First Life.”3 In those articles I cited research demonstrating that previous to 3.5 billion years ago most of Earth’s microbes delivered to the Moon as a result of meteoritic impacts arrived via low-velocity, oblique-angle trajectories.4 Hence, there is an excellent chance that future lunar explorer missions could capture pristine fossils of Earth’s first life and determine who got the origin-of-life model right: the theists or nontheists. These fossils will never be found on Earth. Earth’s geological activity has destroyed them. However, the lack of geological activity on the Moon implies that the fossils of Earth’s first life will be there in an undisturbed state.
I had the opportunity to speak to the astronomers and astronauts at NASA Houston shortly after I wrote my article in which I encouraged them to return to the Moon with a different mission—to find the fossils of Earth’s first life. I explained that public support for such a mission should be very high since 100 percent of the U.S. taxpayer base is either a theist or a nontheist.
Will we ever find viable Earth life on other solar system bodies? I am convinced the answer is no with the possible exception of the upper clouds in Venus’s atmosphere. The conditions in interplanetary space and on other solar system bodies, besides Earth, are extremely hostile for the long-term viability of any Earth microbe. We could be lucky enough to find microbes from Earth on other solar system bodies that very recently arrived there in such a very brief time period (less than several years) that they are still viable. However, the probability of this happening is extremely remote.
Will we ever find indigenous life on other solar system bodies? Here, I am even more confident that the answer must be no. I addressed the possibility of life originating on another solar system body besides Earth in the book Fazale Rana and I wrote, Origins of Life, chapters 14–16.4 In that book, I explain why it is not possible for life to originate and survive on any other solar system body besides Earth.