Interstellar object may have been alien probe, Harvard paper argues, but experts are skeptical

What's really fascinating about Oumuamua is that experts have no fucking idea what it is. It's the first confirmed object to have entered our solar system from another solar system, and the jury is out on what it is. It's been a comet, an asteroid, a planetary fragment, just a big rock, maybe a light sail... Nobody can say for certain. I think that's exciting. We're not even sure where it came from, though we have a few candidates.

I hope we launch something to catch up with it someday to figure this one out. That's not a trivial exercise, but I'd love to see it done.

Here's a pretty interesting article about this paper from last week: ‘Oumuamua, Thin Films and Lightsails