March 7, 2021

Oumuamua – picking through the aliens’ trash.

Recently, Harvard Professor and astrophysicist Avi Loeb has been granting a number of interviews in support of his latest book, Extraterrestrial. While Loeb’s impressive list of credentials spans many decades across numerous countries, he most recently gained international attention for his theories regarding Oumuamua, the interstellar traveler that passed through our solar system in 2017.

One of the aforementioned interviews Loeb granted was with Ryan Sprague on his Somewhere in the Skies podcast. It’s a fascinating discussion I would definitely recommend if you missed it. But to modify a classic premise in the field of ufology, extraordinary theories require extraordinary evidence or you leave yourself open to competing ideas.

You’d obviously be forgiven to ask whether or not I would use my barely literate educational background (at least by comparison) in opposition to an intellectual giant like Avi Loeb. But… of course, I would. I’m paid to be a cantankerous generator of opinions for a living. So let’s look at a couple of the main premises that Loeb brings up and consider what the possibilities might be.

Loeb further concluded that it might be nearly paper-thin. And if so, it seemed unlikely to be some normal “rock” hurtling through the blackness of space and it might be some form of a solar sail.

Loeb’s primary contention is based on the limited amount of data we received in terms of the sunlight reflected from the object. This datum indicated that the object was very long and narrow. Adding in the unusual “push” the object appeared to receive from the light of the sun, Loeb further concluded that it might be nearly paper-thin. And if so, it seemed unlikely to be some normal “rock” hurtling through the blackness of space and it might be some form of a solar sail.

Fair enough, I suppose. We never obtained any direct photos of the object due to how late in its transit Oumuamua was discovered. In an infinite universe, anything is possible. But this isn’t a shape we normally observe in the flotsam and jetsom we’ve found drifting around in our own solar system. Perhaps it’s true. It could have been a remnant of an alien probe that had died at some point during its journey through the cosmos.

The larger point I wanted to address is the viability of looking for examples of potential “alien trash” that comes careening through our own solar system.

The larger point I wanted to address is the viability of looking for examples of potential “alien trash” that comes careening through our own solar system. Astrophysicists described it as the “first” such object we’ve observed. But it appears obvious that this is only because we’ve just recently deployed the sort of technology capable of detecting such interstellar visitors and separating them from the rest of the leftover debris circling the sun since the formation of our solar system. Such items have likely been zooming past us undetected for the entire history of the sun and its various orbital bodies.

Further, physical objects fly through space in a relatively straight line, subject to the gravitational influences of the bodies they pass. Radio transmissions spread out in all directions, albeit decreasing in strength as they disperse. The number of radio waves we receive must be vastly greater than the number of physical objects that just happen to zoom through our neighborhood.

In his interview with Ryan Sprague, Loeb suggests that looking for alien technosignatures in the form of such galactic wanderers might be one of the better ways of detecting fingerprints of alien civilizations. Is that a reasonable premise? Up until now, such searches have relied on the radio emissions we detect from around the galaxy through the work of groups like SETI.

If we were to detect anyone, it would likely be through their broadcasts of the Proxima Centurian version of I Love Lucy.

To date, I’ve not seen much promise in detecting alien technology by listening to radio waves. I’ve written about this in other forums, but there seem to be multiple shortcomings in the idea that a potential extraterrestrial intelligence is conducting all of their communications business via the same technology we use today. It’s problematic at best. I’ve long assumed that a sufficiently advanced species would be conducting most of its communications via some form of ansible, undetectable by any snoops listening from points in-between. If we were to detect anyone, it would likely be through their broadcasts of the Proxima Centurian version of I Love Lucy.

So Avi Loeb is right, yes? Pawing through the aliens’ junk as it drifts through our solar system could be a prime way of finding at least remnants of their technology. Well… maybe. I’m not saying we shouldn’t be keeping our eyes on (and above) the skies and everything streaking through our galactic neighborhood, if for no other reason than to avoid being struck. Who knows? We might strike gold.

But given the size of the galaxy, the number of times that any bit of junk blows past us is likely rather rare. And how many of those bits of debris might turn out to be alien technosignatures? It just seems as if the vast majority will be actual rocks and other debris such as the clutter that fills our own solar system.

To be sure, we should be looking. Why pass up an opportunity? And we should keep listening as well, though nearly all of the signals we’ve detected thus far have at least some plausible, natural origin. But until we can vastly extend our reach into the cosmos with our technological ears and eyes, we might want to focus more on whether or not an intelligent non-human civilization has saved us the trouble and is leaving signatures here on our own planet even as we debate these larger issues.