Astronomical distances, light speed, and uncertainty

[longship]

4. Well, a couple of assumptions help.

First, the Copernican assumption that there's nothing special about our location, or at least not extraordinary. That the universe out there resembles the universe here.

Second, that nature doesn't have a separate version of reality in different places in the universe. The scientific principles active here equally apply out there. We can test this by our distant observations. The fact that we can make sense of what we see out there with the models that work here attests to the probability that it's true.

But Brian Green talks a lot about multiverses. I would say that that is mere speculation, as is the String Models that predict it. But Green is invested in Strings too, so that's not surprising. No comment on that other than to state that I am not a very big fan of Strings. I do like Brian Green, though. Funny about that.