So, high-powered satellite with hyper-precise hyper- powered long-range laser etching capability... nah, scratch that, the comet is probably rotating in some random fashion that'll make the writing a scrawl.
Maybe there's a way to figure out its rotational axis and speed so that the laser can do some dot matrix style letters.
Yeah okay so the Comet's surface will burn it off as it gets closer to the sun. Maybe we can zap it as it's getting further away...?
Too bad we missed Neowise. An Oort cloud wanderer would've been the perfect candidate.
I suppose we could just spell it out on Mars with a rover. But where's the challenge in that?
Maybe we could just build a comet? Glue together some space junk onto an engine that we lift?-- RayfordSteele, Jun 21 2021 CHA https://the-tick-an...andom.com/wiki/MoonNow HA [AusCan531, Jun 22 2021] "Kilroy was here" is a bit... common. Needs to be something at least a little mysterious, like (perhaps) half a croissant?-- neutrinos_shadow, Jun 21 2021 Partially baked on the animated series "The Tick". The villian Chairface, started writing his name on the moon using a laser before he was interrupted by the hero. The moon said "CHA" for awhile until The Tick arranged for the "C" to be erased. As far as I know, it's been "HA" ever since. [link]-- AusCan531, Jun 22 2021 Common for a particular planet in the unfashionable portion of the galaxy, perhaps. But not for comets on their way to the Oort cloud.-- RayfordSteele, Jun 23 2021 Good call, a1. I was thinking of that myself. Also, with an orbital period measuring in the millions of years, there has to be a good science fiction story in there somewhere, surely?-- DrBob, Jun 27 2021 Any such plaque must include the classic nose-over-the-wall image.-- pertinax, Jul 04 2021 random, halfbakery