I agree it's very unlikely that it's something of artificial origin, but if it's just a rock it's far from uninteresting. It would be the first material recovered from outside our own solar system. It could be surprising in all kinds of ways.

Positive confirmation that physics and chemistry works similar elsewhere to how it does in our solar system is a big deal.

We suspect it does, but having material in hand from somewhere else is a huge additional data point.

Why would physics be different in a neighboring system? Are there theories here? And if it enters our system, wouldn’t it be bound to our physics? How could you even know it was different before?

That’s something I hadn’t considered. Quite valuable understanding!

Yes, it would be very interesting if there was a material in it that hasn't been discovered yet. I imagine there are conditions out there, way out there, that bring forth conditions that aren't available here that could create new things not seen here.

This is a fascinating area. Of we do have "materials" here that came from outside of our solar system because we all contain atoms with higher atomic numbers than helium, like carbon, oxygen etc, that have been through multiple solar "cycles" that gradually make higher atomic number atoms as stars go through the ages. So you and I are both made of matter that came that way, from outside the solar system.

Of course it's different if we have rocks or some such that we could tell came directly out of the solar system, and not assembled directly here.

Well no gold was formed on earth. It all comes from stars. I'm more meaning things that would be uncommon in the universe, like perhaps being very close to a pulsar for millions of years.

It seems to me that we know so little about the universe that we can’t say if it’s likely or unlikely.

We don't know much, but I do think we know enough to say it's unlikely. We've never seen any evidence for intelligent life outside of Earth. Using Bayesian logic, that gives pretty good odds in favor of it being of natural origin.

Not that I think an alien artifact is likely either but an interesting question is whether we could recognize such an artifact if we found - especially if we found nothing but basically twisted wreckage.

Let's suppose we shoot a piece of steel in space and after one billion year it splashes into an alien ocean. Natives take it ashore. Would they be able to understand that after all the exposure to radiation and possible collisions it's not only a lump of iron, carbon and a few other elements but something made by people somewhere else? Would it look like a normal meteor or its composition and structure is different?

Not an expert but I'm pretty sure it'd be easily identifiable as artificial because of the uniform composition and regular grain structure in steel. I think it would not only be clear that it was refined because of purity but also that it was far more regular than something natural. [1]

1. https://youtu.be/uG35D_euM-0

Some crystals are very regular.

https://en.wikipedia.org/wiki/Crystal#/media/File:Ho-Mg-ZnQu...

There might be a different isotope signature, that might give its origin away.

If it appeared worthy of analysis.

It will certainly look unusual. It's not clear to me that it will look artificial (we are pretty bad at deciding that one), but it won't look like anything else around it.