is that, despite what some experiments have reported, that the space we live in isn't Euclidean (it just appears so on sufficiently small scales (as in a durned sightlarger than galazies 'small') and that some of the oddness we are trying to grapple with comes down to the effect that has on how things like gravity and electomagnetic radiation interact with the universe about it.
It seems to me that we ought to be in a universe with elliptic geometry*, which implies that if you model the universe as being Euclidean, your calculations fail over large distances, because ther eisn;t as much 'there' 'Out There' as you think there is. With interesting possible consequences for how gravitation behaves over large distances. Which, sadly, I'm not up to working out (or haven;t managed to yet, anyway).
But I'm strictly an amateur, that simply enjoys thinking about this stuff for fun. I look forward to finding out what the active scientists find out over the next few years..
*because, for various reasons, I'm convinced that what we consider to be the universe must be the inside of something that is, functionally, a humungous black hole. Let's not go into whether that may be part of a larger 'multiverse' just now, or we'll be here all weekend, and there's a bottle of wine at home with my name on it!