It's Never Aliens (Until It Is)
On holding skepticism and hope at the same time, and: The Wow! Signal: Aliens premieres tonight!
Earlier this year, all eyes were on Venus: a team of scientists announced that they had detected a whiff of phosphine, a smelly gas that (when found on small, rocky worlds like Venus) is thought to indicate the presence of life. As I wrote then, the results are potentially exciting, but haunted by a lot of open questions that require further investigation. But even before the phosphine results were publicly announced, the space cat was very much out of the bag (which is reason #1 that no one is hiding aliens from you: astronomers and astrobiologists are constitutionally incapable of keeping a secret), and on social media, the evergreen rallying cry began to bubble forth:
"It's Never Aliens!"
This morning, "it's never aliens" is making the rounds again. Because of my peculiar choice of career, I awoke to a ~very casual~ email from some colleagues that (paraphrasing) said, "Hey, there's a signal that could potentially be coming from Proxima Centauri but probably isn't. Probably." I groggily reread it, and took a moment to savor the surreality of it being totally normal for me to get an email that says something like that (in addition to just being an astrobiologist, I am on the Breakthrough Listen Science Advisory Board, so the email was updating us on what's going on). The upshot is that the Breakthrough Listen team, which is a big search for SETI signals, has detected the kind of narrowband emission they are looking for-- but the catch is that they think it's probably from something on Earth. Which, actually, is pretty common-- they scan the skies all the time and get lots of detections of narrowband emission, but most are easily explained away as errant signals from Earth that happen to end up in the telescopes. Sometimes, though, it's harder to eliminate those signals as having come from space, and that's where things get tricky. What's trickier is then when the press picks up the story, and then: the chorus of It's Never Aliens begins again!
"It's never aliens" is, of course, something that few scientists mean literally-- in my experience, most astronomers are pretty optimistic that somewhere out there, there must be alien life of some sort. And of course we are: the subfield of astrobiology is dedicated to understanding and finding life in the universe, so if we all went into it utterly convinced it didn't exist anywhere, it would be one hell of a masochistic career choice.
Rather than being any literal declaration of disbelief, cries of "it's never aliens" encompass a wide range of social anxieties at work in how astrobiologists think and feel about their line of research. Some of these are just the healthy dollops of skepticism that scientists use to garnish just about everything: observational scientists (meaning those who work with data) are investigators, and our task is to follow every clue. We rest only after we have convinced ourselves that we've found an explanation that is the most likely, and that means that we believe our explanation is more likely than any other. One of the cultural norms that accompanies this approach is the belief that, as Carl Sagan put it, "extraordinary claims require extraordinary evidence", or in other words, that because boring things happen more often and usually explain the things we observe (e.g. probably a gust of wind blew your door shut, rather than a ghost) you need very strong evidence to claim something more exotic (you know, like aliens).
As I've written before, extraordinary claims in science are often a bit more complicated than that, but the Sagan Standard, as its known, is a well-loved bit of folk wisdom amongst scientists. So important is this cultural norm that extraordinary claims can be seen as a betrayal, and claims of "exotic causes" like aliens might be interpreted by one's fellow scientists as anything from stupidity, to treachery, to fatuous fame-seeking. Those interpretations can also be gendered, racialized, and otherwise infused with the dynamics of power that exist nearly everywhere in our culture-- e.g. in the case of the phosphine on Venus results, it's hard not to see some sexism in the outsized scrutiny a team led by several prominent women received, especially when compared with past outlandish claims regarding alien life (as I wrote about in the article linked above).
However, it would be unfair to locate the "It's Never Aliens" impulse solely within individual scientists, because there is some essential historical context here: the so-called "giggle factor". When SETI (the search for extraterrestrial intelligence) efforts were still in early days, it enjoyed at least modest government funding and support. But that didn't last-- and in fact, it was roundly mocked in Congress for being a ridiculous search for "little green men". Today, part of the reason that recent announcements come from groups like Breakthrough Listen (rather than NASA or the National Science Foundation) is that Breakthrough Listen is funded by billionaire Yuri Milner, rather than by the government agencies that support most scientific enterprises. To make things even more tangled, recent changes in what kinds of proposals can be submitted for government funding-- e.g. to allow agencies like NASA to fund searches for "technosignatures", or SETI signals-- have only happened because of the efforts of scientists involved in projects like Breakthrough Listen to convince Congress to include that language in the budget. So in short, someone had to spend a bunch of money to fund the science first, to make it possible for scientists to even ask for money from the usual sources without being laughed off Capitol Hill.
All of this is to say that for folks who have been working in astrobiology and/or SETI for a while, extraordinary claims also come with actual personal risk-- the gains made in support for our research over the past several decades have been hard fought and won, so any discovery announcement that looks sloppy or sensational risks undoing years and years of work. For these reasons, some astrobiologists don't even like the word "alien"-- to them, it conjures a bug-eyed green caricature that they feel undermines their scientific credibility-- so "It's Never Aliens" is a kind of evergreen "bah humbug".
But, not everyone feels that way: I certainly don't. I think in part because of my role as not just an astronomer, but someone who talks a lot about science with people who aren't professional scientists, I am pretty comfortable holding healthy skepticism and outlandish optimism at the same time. Outside professional astrobiology circles, people's curiosity about life in space isn't really divided between "serious astrobiology" things like looking for biosignature gases in the atmospheres of planets around other stars, and little green men aboard flying saucers. That divide is a cultural one, one that astrobiologists often ascribe great importance to because of its historical and potential future impact on their livelihoods and self-perceptions, but honestly for most people it's on a continuum of possibility, and there's a lot more nuance in what people believe might be out there than scientists often give non-scientists credits for.
In the case of the signal making the rounds in the news today, the team doesn't seem to think this particular signal is aliens, and they know the data and software better than anyone-- so while I look forward to hearing more details, I'm inclined to trust their intuition while they figure it out.
But, while you're waiting: tonight at 8pm CT we have a new episode of The Wow! Signal out, and it is (coincidentally) all about aliens! I even wrote a song for this episode called "It's Never Aliens (Until It Is)", which is all about the balance of skepticism and optimism that characterizes so much of science, but particularly the search for life beyond Earth. If you watch live with us, there will be a chat with myself, Meredith, and Chris from our quarantine stronghold in the belly of the Adler Planetarium-- and if you're in Chicago, you can also pick up a specially-brewed beer collaboration with the Adler called Space for Everyone!
I hope you love the episode, and remember: hopefully one day-- probably not today, but someday-- it WILL be aliens.
