Faster than a speeding light sail: a note on Avi Loeb’s thesis concerning the artificiality of ‘Oumuamua

In a recent discussion with a friend about Avi Loeb’s hypothesis that the object ‘Oumuamua displayed behaviours consistent with its being an artifact of nonhuman technology, namely a light sail, one problem with the consistency of his thesis struck me.

A root problem with Loeb’s thinking that I have noted at length here is the unproblematic spontaneity of the very idea of nonhuman, extraterrestrial technology of the kind Loeb proposes ‘Oumuamua might be. It’s precisely the way the idea seems unquestionable, even as a speculation, that I argue is a mark of its being ideological and calling for scrutiny. (Interested readers are encouraged to click on the ‘Avi Loeb’ tag to access previous posts on this topic).

However, aside from “merely” philosophical reflection if not critique of Loeb’s thesis, one might propose a problem with its internal consistency. If we suppose ‘Oumuamua to be a light sail, then it must have originated, however long ago, from a relatively advanced extraterrestrial civilization. If said civilization were sufficiently sophisticated to imagine, design, and manufacture a light sail, is it not likely the same civilization had at the same time if not earlier developed a form of artificial communication that employed some frequency of the electromagnetic spectrum, e.g., radio? If this same civilization were to possess some such communications technology, then it seems arguable that signals from this civilization would have reached earth long in advance of a light sail, given their relative velocities. In the same way, long before any light sail or subluminal spacecraft from earth will reach another solar system, all the EM emissions from our communications technology will have reached that solar system long in advance. Therefore, subject to a whole raft of assumptions, admittedly, imagining a light sail arriving in our solar system suggests that signals, intentional or otherwise, from the home civilization of said light sail will have alerted us to that civilization’s existence long in advance of the arrival of their spacecraft.

Just a thought, and one I doubt is original to me. (Nor should the implications of this argument for the Extraterrestrial Hypothesis for the origin of UFOs/UAP be underestimated…).