The question asked in the title of this post is one I have been pondering for the most part of a decade now, ever since I saw the image, shown in Figure 1, of the galaxy PGC54559 (popularly known as Hoag’s Object) in 2010, following several months of thinking about what Kardashev Type III civilisations might look like.

I had seen it before, of course, as it is one of the most striking of the many superlatively beautiful and photogenic images that the Hubble Space Telescope has made available to humanity as part of its astounding legacy. But when I saw it again on NASA’s Astronomy Picture of the Day on that day in late August 2010, I saw it in a quite different context – one prompted by having thought deeply for some months about what galaxy-scale macro-engineering might look like. And so, picture it: that idea, coupled with that image, and you can see, I hope, how the question asked in this post’s title would come immediately and insistently to mind (at least, for me!). As I thought about it even more for a few weeks, I even ended up tweeting about it – so strongly had the idea installed itself into my head! – https://twitter.com/JosephVoros/status/26173613969 (see Figure 2).

In fact, there were five tweets in all (first, second, third, fourth:shown here, fifth) which, fortunately, were so far in the distant past of the tweet-stream that when I decided to delete thousands of tweets as a precursor to getting off social media entirely a couple of years ago (well, it worked, for a while…), they were no longer easily accessible, and so survived the bulk-cull. Thus, luckily, they still exist as an historical record of what was at the time an hysterical time of intense SETI-focussed cogitation!