I had great hopes for this guy, but after some reflection, I'm starting to think its just an ordinary piece of space debris. The only reason we haven't seen one before is that we only just recently developed the technology, and since we deployed that tech, we've already found two interstellar interlopers. Look up 2I/Borisov. Both of these visitors have definitely been identified as extrasolar by their orbits, but neither is behaving like an alien spacecraft. They move like ordinary space junk would be expected to.

It seems reasonable that the galaxy is littered with planetoids, meteors and comets that have been ejected from their parent star systems, far away and long ago. And now that we can find them, they will start turning up more and more often. The only thing about this one that is really remarkable is its long, skinny shape--no natural process that we know of could produce an object with this aspect ratio. But we don't really know that, do we? The only evidence we have for its shape is a light curve, and that could be the result of some unusual set of surface markings or blotches that reflect sunlight that way as it tumbles through space. As for its unexpected acceleration, we've seen that behavior in comets, caused by outgassing. 2I/Borisov was a comet, not just a rock, but associated volatiles, too.

Still, the idea that we are visited periodically by extraterrestrial objects is fascinating. Perhaps someday we may travel to one and take a good look at it. And maybe the next one won't be just a lump of ET slag or a drifting iceberg. Maybe it will be a whole planet. We already have evidence that there may be multitudes of rogue planets, cold solitary worlds, prowling around the yawning darkness between the stars.