Are we alone in the universe? Could alien life exist, and if so, is there a reasonable explanation for why—scientifically speaking—we’ve never seen any evidence for it?
This is a question many have asked over time, although it is most famously attributed to physicist Enrico Fermi, for whom the so-called “Fermi Paradox” is named. The general premise has to do with what appears to be the contradictory nature of high probability for the existence of alien life, versus the paltry evidence to support it.
As the name suggests, the idea is famously attributed to Enrico Fermi, and was suggested under circumstances of such fame in the scientific literature that they border the mythical. As the story goes, Fermi was on his lunch break with fellow Los Alamos employees Emil Konopinski, Edward Teller, and Herbert York in 1950, when discussion about a funny little cartoon depicting dumpster-diving aliens returning from a visit to New York caught their imagination. Musing more broadly on the subject of aliens, Fermi is said to have asked, “where is everybody?”
It was a decidedly scientific question, despite its simplicity: where is the evidence of aliens, if it otherwise seems so likely that we aren’t alone in the universe?
Taking a stab at this famous conundrum, a recent paper published by a team of Oxford researchers with the University’s Future of Humanity Institute argues that the absence of evidence may, in fact, actually be evidence of absence: we may be alone after all.
The problem, researchers Anders Sandberg, Eric Drexler and Toby Ord argue, has a lot to do with human expectations, which build on earlier models for the likelihood of whether life exists elsewhere; namely the Drake equation, which supposes a decent probability that alien civilizations exist, which are technologically advanced to the degree they would be potentially observable to us.
As stated in a portion of the paper’s abstract:
We show that this conflict arises from the use of Drake-like equations, which implicitly assume certainty regarding highly uncertain parameters. We examine these parameters, incorporating models of chemical and genetic transitions on paths to the origin of life, and show that extant scientific knowledge corresponds to uncertainties that span multiple orders of magnitude. This makes a stark difference. When the model is recast to represent realistic distributions of uncertainty, we find a substantial ex-ante probability of there being no other intelligent life in our observable universe, and thus that there should be little surprise when we fail to detect any signs of it. This result dissolves the Fermi paradox, and in doing so removes any need to invoke speculative mechanisms by which civilizations would inevitably fail to have observable effects upon the universe.
As Vox reports, “the paper’s authors do not appear to be making any definitive claim about whether or not aliens exist; simply, our current knowledge across the seven parameters suggests a high likelihood of us being alone,” noting that with new forthcoming information, the Oxford team “would update that likelihood accordingly.”
Naturally, criticisms will arise from such a claim. To consider just a few of them here, it seems difficult (even in probabilistic terms) to suggest the unlikelihood of alien life elsewhere given the expansiveness of the universe, let alone the fact that so little of it has been explored by humans. Also, this isn’t the only solution to Fermi’s paradox that has appeared recently; there are constantly a variety of contrasting views about what might, or might not, explain it.
Sure, Frank Drake’s famous aforementioned equation also focused on the question of alien life, and more specifically, those civilizations which would be sophisticated enough that any evidence for their existence would be detectable by us. While we might expect that a significantly advanced alien civilization would leave an easily discernible cosmic footprint, it may just the opposite: what if our cosmic neighbors have advanced to the point that they employ what we might call “cleaner,” energy sources and other sustainable technologies… and thus, maybe they’re less easily detected, as well?
Bottom line, it’s nearly impossible to conceive of what alien life and their technology would be like without anthropomorphizing the argument (that is, projecting our own ideas, values, and expectations onto things). However, there are at least a few other problems with the Oxford study, one of which has to do with what Fermi actually said about aliens in the first place.
The paper leads off, naturally, with the famous story of the Fermi lunch at Los Alamos. “While working at the Los Alamos National Laboratory in 1950,” the paper reads, “Enrico Fermi famously asked his colleagues: ‘Where are they?’ ” Although it’s a famous and often-cited story, some have questioned whether it’s entirely true and accurate. Robert H. Gray, writing for Scientific American in 2016, noted that Fermi’s fellow diners at the famous lunchtime discussion had a pretty clear memory of the conversation when asked about it years later, and noted that Fermi hadn’t been merely discussing where all the aliens were. More specifically, they had been talking about interstellar travel, and why there was so little evidence in the specific form of alien spacecraft:
Both York and Teller seemed to think Fermi was questioning the feasibility of interstellar travel—nobody thought he was questioning the possible existence of extraterrestrial civilizations. So the so-called Fermi paradox—which does question the existence of E.T.—misrepresents Fermi’s views. Fermi’s skepticism about interstellar travel is not surprising, because in 1950 rockets had not yet reached orbit, much less another planet or star.
All discussion of UFOs aside (since, to date, there is nothing that conclusively proves that these objects are in any way related to alien spacecraft), the minor detail of what Fermi actually meant may not be enough to change the outcome of the Oxford study’s findings, which purportedly employed “millions” of logarithmic simulations to arrive at the mathematical conclusion that we’re 53 to 99.6 percent likely to be the only civilization in the galaxy. Further, we run a 39 to 85 percent chance of being the only intelligent life in the entire observable region of the universe.
However, if we consider that the basic averages of the Oxford study boil down to there being roughly a 50% chance that we’re alone in the universe, our potential desolation still amounts to a coin flip: either we’ve got some interstellar neighbors out there somewhere, or we do not. We simply don’t know yet.
So maybe it’s a little too soon to be cashing in on whether aliens exist or not; we still have an awful lot of the universe we’ve yet to explore, and innumerable scientific advances that will be required before we can embark on our ultimate journey. For the time being, maybe it’s best to keep an open mind, and see what the innovations of the coming years have to say about what may await us out in that great and final frontier.