[Programming note: We have a newly extended list of options for labeling our blog items. After the old standard categories of “news" and “opinion," we also have the categories of “analysis," “perspective" and “review." For some reason my blogging software defaults to “perspective," which sounds to my ear like “opinion lite." No raving allowed. No promiscuous opinionating. I will continue to lobby for a “blather" category. And “drivel."]

Thursday, the inbox featured a bulletin from Harvard, saying scientists think the Fast Radio Bursts from deep space could conceivably be coming from aliens zooming around the cosmos in laser-powered light-sails. I think I am summarizing this accurately and without exaggeration. Hang on, let me call up the news release. Oh, yeah, here it is:

Frowny-faced skeptic though I may be, one can make the case that the detection of alien civilizations would involve something like this — anomalies picked up by telescopes for which there is no obvious natural explanation. That’s what Freeman Dyson told me something like 20 years ago: Someday we’ll see something. The something in this case are the FRBs, first detected in 2007. They’re very brief flashes of light in the radio portion of the spectrum. There may be hundreds of thousands of them pinging the Earth every day from all points of the heavens. If the FRBs are artificial in origin, the implication is that the universe is lousy with alien light sails. From the news release:

To power a light sail, the transmitter would need to focus a beam on it continuously. Observers on Earth would see a brief flash because the sail and its host planet, star and galaxy are all moving relative to us. As a result, the beam sweeps across the sky and only points in our direction for a moment. Repeated appearances of the beam, which were observed but cannot be explained by cataclysmic astrophysical events, might provide important clues about its artificial origin.
[Harvard professor Avi] Loeb admits that this work is speculative. When asked whether he really believes that any fast radio bursts are due to aliens, he replied, “Science isn’t a matter of belief, it’s a matter of evidence. Deciding what’s likely ahead of time limits the possibilities. It’s worth putting ideas out there and letting the data be the judge.”

I did what I always do in a situation like this, which is write to Seth Shostak, ace astronomer at the SETI Institute. Seth has spent his career looking for signals from advanced civilizations, so this is right up his alley. Seth quickly wrote back, saying this was “a neat idea” but expressing a fair bit of skepticism:

So … could it be that we’re looking at Klingon Cape Canaverals?  That we are occasionally catching the flash of the mother-of-all-lasers as they boost alien craft to speeds that would allow them to travel from star to star quickly enough that the passengers who boarded would still be alive to get off at the other end?  Yes, that’s possible.  But on the other hand, it’s just about always possible (and inevitably tempting) to ascribe puzzling astronomical discoveries to the work of advanced beings.  It was much more exciting to think that pulsars might be messaging apparatus used by extraterrestrials, or that flickering quasars were just another effort by cosmic company to get in touch.  But in the end, it turns out that Nature is both ingenious and full of surprises, so I’d keep the “alien explanation” for FRBs at the bottom of the drawer for now.
In addition, the repeated nature of at least one of these FRBs would require a fairly specific (and therefore, suspect) geometry as well as a busy schedule on the part of the supposed alien launch team.
Never say never, of course, and this is an appealing idea.  But my first reaction is to bet on the workings of Nature, rather than that of aliens with a hankering to roam.

So let’s go with that for now.

Further reading: