‘Oumuamua, SETI, and the media

Avi Loeb

Avi Loeb is the chair of the astronomy department at Harvard, a distinguished and well cited astronomer (he has an h-index of 87), and the chair of the Breakthrough Starshot initiative. He’s a strong proponent of making sure that science doesn’t succumb to groupthink and champion of outré ideas.

He also has been making headlines recently for articles he has co-authored, interviews he has given, and popular media columns he has written about the possibility that fast radio bursts, and now ‘Oumuamua, are artificial in origin. This has created a great deal of buzz in popular culture and a lot of hand-wringing and criticism on social media by scientists who find his actions irresponsible. Many have asked my opinion, so I’m collecting my many thoughts on the topic in this post.

I am happy to defend Avi on these grounds:

  • He is driving us to have an important conversation about what “acceptable” SETI research looks like, and in this conversation I’m mostly on his side. He’s essentially moving the scientific equivalent of the “Overton Window” towards SETI, and that’s a good thing. These are exciting and interesting questions and we should not let the face-on-Mars/Ancient-Aliens/UFOlogy types prevent us from discussing them.
  • He is using tenure and his stature the way we all imagine it’s supposed to be used: as a shield so that he can explore potentially unpopular research avenues without fear of retribution or ostracism. We all imagine that’s what we would do in his position (I hope!) but too often it ends up just being a club to get junior scientists to conform to one’s vision for what “proper” science looks like and what “good” problems are.
  • The papers he and his postdocs are writing are important first steps in making Solar System and other forms of SETI a serious academic discipline.
  • He is being a role model for how scientists can explore outré ideas and spend an appropriate amount of their time on potential breakthroughs.
  • He is putting SETI in the public eye and doing a lot of outreach.

Avi wouldn’t be pushing the envelope hard enough if he weren’t getting some pushback, and indeed there is plenty of fair and good-faith criticism that can be made about his approach (not all of which I agree with):

  • The degree of certainty he expresses in ‘Oumuamua being artificial does seem unwarranted to me (though to be fair I’ve always been an ‘Oumuamua-might-be-artificial skeptic.)
  • Given the way we know the press (especially the yellow press) will handle any story about “aliens”, one can argue that the “extraordinary claims require extraordinary evidence” maxim is especially applicable to SETI (I’ve made this argument strongly when discussing my own research in the press.) Avi could hew more closely to this maxim.
  • The tone of his papers and his public comments are quite divergent. The body of the paper on ‘Oumuamua-as-lightsail, for instance, has a brief mention about the potential of the artifice of ‘Oumuamua at the end, but most of it is about the perfectly general problem of thin objects in interstellar space. Snopes highlights this divergence well pointing out that the paper is quite sober and restrained compared to some of the media coverage. (It’s true that the title and abstract of the paper are about ‘Oumuamua specifically, and that it serves as the case study for the whole analysis.) Avi’s public statements are much less conservative and equivocal.
  • He is not just quietly following the evidence; he is using his platform to have a very public and high-visibility discussion about his research. I will concede that Avi is an exception to my earlier (somewhat petulant) protest that SETI scientists are not in it for the attention. That said, I will object to anyone who would claim Avi is only in it for the attention, or that such attention is inherently a bad thing.
  • Many of his papers are de novo explorations of topics like the fate of comets in interstellar space, with little connection to the substantial amounts of work that has already been done on the topic, and his papers would be better and less naive if they had a closer connection to this prior work rather than starting from scratch.

More broadly, let’s look at two threads on Twitter criticizing Avi. I’ll start with this one by Bryan Gaensler:

Bryan makes the rather Popperian argument that if your model is too flexible then it can’t be falsified, so you’re not doing science.  The implication is that since we don’t have a good model for aliens, we can always play the “aliens of the gaps” game and so SETI isn’t good science unless it’s looking for unambiguously artificial signals like narrow-band radio waves.

This argument isn’t as tight as it seems. Most interesting new theories start without concrete predictions—General Relativity was so hard to use that even Einstein wasn’t sure what it predicted (he got the deflection of starlight wrong the first time he calculated it; he wrote a paper saying gravitational waves don’t exist). Theories don’t spring fully-formed from theorists’ heads; many important breakthroughs start with something less than quantitative or precise (“maybe we need to modify gravity”; “maybe there is a new subatomic particle involved”) and let the data guide the theories’ details.

This is the normal progression of science. SETI is no different, and so no less scientific.

Then there is this one, by Eric Mamajek, which I mostly agree with:

It’s mostly fine through tweet #9, but then he conflates things in the last tweet using an unwarranted leap of logic.

Up until then he had been criticizing the Holmesian logic of how ‘Oumuamua must be alien because we had ruled out natural explanations. I quite agree with him.

But in the last tweet he jumps to criticizing even bringing up the hypothesis of ETI’s in general, implying that scientists who do are pulling a Giorgio Tsoukalos. (There’s also the assertion at the end such anomalies will “inevitably” turn out to be not just natural, but mundane, which is obviously not strictly true.)

But Tabby and I weren’t pulling a Tsoukalos when we submitted our proposal with Andrew Siemion to NRAO to study Tabby’s Star. We really weren’t. I have clarified the actual events with Eric, so I’m pretty sure that’s not what he meant to imply here, but that is how this tweet reads.

Bryan makes a similar (but softer) implication in his final tweets:

We all would! Indeed, Avi Loeb suggested that Breakthrough Listen point Green Bank at ‘Oumuamua1 because he understands very well that the proof of alien technology is something like the bullets on Bryan’s list.

But the implications of these tweets aren’t just wrong, they’re harmful to the field of SETI. A very plausible path to SETI success will be that we will see something strange (not “Eureka!” but “That’s funny…” as the old fortune quip goes) and eventually, after lots of follow up, we might find the smoking gun, or perhaps it will just end up being a proof by exclusion.  As I wrote in 2014:

Artifact SETI can thus proceed by seeking phenomena that appear outside the range that one would expect natural mechanisms to produce. Such phenomena are inherently scientifically interesting, and worthy of further study by virtue of their extreme nature. The path from the detection of a strange object to the certain discovery of alien life is then one of exclusion of all possible naturalistic origins. While such a path might be quite long, and potentially never-ending, it may be the best we can do.

Communication SETI, on the other hand, shortcuts this path to discovery by seeking signals of such obviously engineered and intelligent origin that no naturalistic explanation could be valid. Together, artifact and communication SETI thus provide us with complementary tools: the most suspicious targets revealed by artifact SETI provide the likeliest targets for communication SETI programs that otherwise must cast an impossibly wide net, and communication SETI might provide conclusive evidence that an extreme but still potentially naturalistic source is in fact the product of extraterrestrial intelligence (Bradbury et al. 2011).

Bryan’s thread and Eric’s final tweet could easily be read to foreclose this sort of research, essentially saying “it’s not worth thinking about the aliens hypothesis until it’s so unavoidable that you’ll get no flak for it” (radio signals à la Contact, the proverbial saucer on the White House lawn, etc.). They certainly make it clear that they won’t hesitate to chastise you on Twitter for going down this road.

But if we want to get to the end of that road, we’ve got to start walking down it at some point, and when the media very reasonably asks what we’re doing so they can report on it to a very understandably curious public, we should be allowed to answer their questions without having our motives (or scientific credibility) questioned by our peers.

In short: your mileage may vary on Avi’s particular style of public communication and conclusions on ‘Oumuamua, but when making your critique please be mindful that you are not slamming the whole endeavor. SETI as a serious science will make hypotheses, explore anomalies, and discuss the possibility of alien technology as the cause, and we need to be able to do so without obloquy from our peers, and without them policing which kinds of SETI we’re “allowed” to work on or talk about in public.

If I seem touchy about this, it’s actually not because I’m smarting from these Twitter threads or anything like that (which I don’t actually disagree with much—in particular I’m friends with Eric and I know I have his respect). As I wrote at the top, I’m glad we’re having this conversation and I hope it continues!

But another purpose of this post is that Avi and I (and other SETI researchers) have advisees that work on SETI and these sorts of messages are not lost on them: these tweets imply that senior people in your field will disapprove of you because of the topic of your research, and they will police what you’re allowed to say to the press, regardless of how good a scientist you are. Keep in mind, “Avi’s” paper on ‘Oumuamua that is being criticized has a postdoc as first author.

So in closing: I pledge to keep the SETI real and well grounded in science, to be responsible in my interactions with the media about it, and to train my students to do the same.

And, I hope my peers will pledge to create a welcoming environment for my advisees as SETI (hopefully!) comes back into the astronomy fold (even when—especially when—they are complaining about Avi).

[Updates: Bryan responds in this thread (click to expand):


1= privately, Bryan clarified to me his tweet was referring to his team’s MWA search for signals, not the search by Green Bank, as I suggested in my post. I should have read Bryan’s tweet more carefully and followed link before critiquing his tweet.

Also, I’ve changed the language about who suggested that GBT observe ‘Oumuamua; Joe Lazio informs me that the observations were made with WVU time following discussions with Breakthrough Listen that preceded Avi’s recommendation. In spite of both errors on my part in the original post, my point that Avi appreciates the importance of dispositive evidence stands.

Also, Avi touches on his motives in this interview:

But the search for intelligent life remains outside the mainstream. I am trying to change that in two ways. First, by speaking out in the way that I did on ‘Oumuamua.



12 thoughts on “‘Oumuamua, SETI, and the media

  1. James Ramey

    Dear Dr. Wright:
    I posted a longish comment a few days ago, but did not get a response and do not see it posted here. Has it been rejected?
    James Ramey, Ph.D.
    Universidad Autónoma Metropolitana, Unidad Cuajimalpa

  2. James Ramey

    I love this discussion, thank you. I am another member of the “understandably curious public” and have found this conversation to be extremely stimulating. Although Loeb’s press-mongering throws down a heavy gauntlet, I have yet to see a plausible alternative explanation for ‘Oumuamua that elegantly addresses the six or seven anomalies he and his postdoc lay out. A few considerations:

    1) If the object is artificial, and is not debris but rather an active probe sent intentionally to the habitable zone of our solar system, the two strategic reasons for this that immediately spring to mind are, on the one hand, altruistic scientific curiosity, and on the other, exploitative (possibly hostile) intentions. Biology and human history favor the second reason, but do not rule out the first.

    2) If serious astrophysicists (and astrobiologists, like Caleb Scharf) think there is a nontrivial chance that the object is an active probe, and if we recognize that such a probe could plausibly have been sent with hostile intentions, then we should be having a conversation about what intelligence it might have gleaned, and how that information could be used to our detriment. Catching up to the object becomes more urgent if it represents a potential threat.

    3) The speed with which we overtake such a probe would be a significant indicator of our civilization’s technological prowess. Several commentators have mentioned that it would be difficult but not impossible to overtake the object with chemical rockets, but we have another, far more powerful propulsion technology: nuclear thermal rockets. Although research was discontinued in the 1970’s, in part because they pose significant environmental hazards, they were brought to a high degree of development by both the USA and the USSR. If revived and implemented, this technology would offer a much faster option for overtaking the object, cutting many years off the timeline.

    4) Another reason to go after the object as quickly as possible, one perhaps more likely to influence government policy in the USA, would be the fear that rival governments could seek to overtake the object in order to exploit it for technology that could confer a major military advantage (this logic was in play during the Cold War). If this were to ignite a new kind of space race (a literal one), then nuclear thermal rocket technology might come to be seen as indispensable. It would be a moonshot with a potential prize much more tempting than moonrocks: unimaginably powerful technology. Even if the object were to turn out to have what Mr. Perry refers to as the equivalent of the Voyager’s Golden Record, would the United States want the Russians or Chinese to obtain that, or vice versa?

    5) And this brings us to a final worry, the possibility that an artificial probe’s main function may NOT be to collect and transmit data directly about our civilization, but rather to act as a kind of technological “alarm”, one which would only send a signal to its makers if a local civilization has reached a the level of sophistication necessary to catch up with it. Thus, in an act of cosmic irony, by competing to chase down the technology contained aboard the probe, the winner of the race could cause it to send a signal leading to an extraterrestrial intervention that otherwise would never have occurred. That signal could activate a possible “array of buoys that serves as a network of relay stations or road posts”, as Loeb puts it, all of which are camouflaged by moving at the Local Standard of Rest (such camouflage could exist for scientific or military purposes). The signal might also take the form of a self-destructing explosion that would both prevent us from obtaining its technology, and alert this camouflaged network to our presence, and our capabilities.

    Loeb may be right (my much maligned gut says he is), but is it wise to publicize the likelihood of advanced technology being aboard ‘Oumuamua? What consequences might that have, here on earth, and beyond?

    I thank you for your time in reading these reflections.

  3. Don C.

    Being overly dismissive of any object as alien would be a mistake, because any alien intelligent enough to send a probe here would certainly know how to fool us by making it look natural. Why would they do this? So that we don’t launch probes at it and possibly damage or destroy it along with the data it is storing on board. So there are a lot of reasons that it could be alien even though the creators didn’t put a billboard on it advertising as much. Keep up the good work Avi.

  4. Tom Perry

    If I may make one more comment (from John Q Public)…and I apologize if this is not original.

    I made a comment somewhere -Twitter, Reddit?- that if -and a very very big IF- `Oumuamua is artificial, what if -another huge IF- it carried with it the equivalent of the Voyagers’ Golden Record?

    Maybe the radio silence of `Oumuamua argues against that.

    The comments suggesting a spaceshot to catch up with `Oumuamua and determine its origin are really interesting but who would justify and sign off on a project of that magnitude? And put their reputation on the line?

  5. Marshall Eubanks

    I think that Avi is trying to justify (and possibly find funding for) a Breakthrough Starshot mission to 1I/’Oumuamua. 1I is not out of reach; for decades and centuries to come it will remain roughly 3 orders of magnitude easier to reach than any star system. A Starshot mission to it would be difficult, but useful. Even if we decide to send a “heavy” probe (i.e., New Horizons size) to 1I (as is discussed in the Project Lyra paper), we won’t know where it is to within maybe a few million km and the probe won’t be able to detect 1I much more than a few million km away. Even if all the Starshot “chiplets” can do is locate 1I, that would be a great help for a future heavy mission.

  6. John Davies

    Three key points about Oumuamua –
    * This is a very odd object
    * We don’t know how often such objects come close to the Sun since we have only seen one
    * Its reachable by a (big) existing chemical rocket (see i4is Project Lyra*) if we launch in the next few years
    If we don’t chase this object and no others appear then we will look like a very stupid species in 10-20 years time.
    See also – i4is.org/what-is-oumuamua-the-loeb-bialy-conjecture-and-i4is-project-lyra

    Note the above is a personal view, not an official view of i4is.org

    * en.wikipedia.org/wiki/Project_Lyra

  7. Tom Perry

    I am a member of the “understandably curious public“. Your blog post was very thoughtful, reasonable and middle of the road, in my humble opinion. It provided a clear rationale for SETI in the Scientific Method. I hope that holds true cause SETI needs both rigorous science and outside-the-box curiousity.

    Regards, and thanks

  8. Tom F.

    It seems difficult to communicate scientific progress to a wider audience. Ideally, there should be a knowledgeable journalist that can translate these findings to others, such as the scientific questions around this asteroid-like object. I read Dr. Loeb’s article (and co-author) which included a SETI hypothesis, but as mentioned above, it did not detract from the theoretical framework of the paper so as to guide others in constraining which models fit the observations.

    The fast radio bursts are also interesting and raise similar questions. Even though there is reporting that these are a single category of events, including in some spoken interviews with experts, the literature generally does not agree with this. It is unknown how many populations of objects are creating the radio bursts. It is parsimonious to at least suggest there are two, but one expert suggested two or three.

    Staying with a Popperian style of science, then continued measurements, as mentioned above for Oumuamua, seems best for falsifying the models proposed for the radio bursts. I see now that these questions may be partly answered via private funding sources, so the typical peer review process is now replaced or mixed with a different communication approach to appeal to these donors.

  9. Paul Gilster

    Jason, a fine article, and I appreciate your concern for your advisees and their reaction to some of the ‘Oumuamua backwash. A welcoming environment within the context of rigorous science seems the least we could ask for as people enter the field. Well stated.

  10. Jim Franklin

    Very well said. I think Avi Loeb should be applauded for sticking his neck out on this. There is nothing wrong with discussing such topics. A lack of radio transmission from Oumuamua does not prove the argument either way.

    I do not hold much faith in Oumuamua being artificial, although it is intriguing on a personal level ( nothing weird or wackey involved) but having an adult debate is healthy snd overdue.

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