How big is the universe?

[PsychoSerenity]

I watched this episode of Horizon the other day, and there's a bit near the end (starting about 45 minutes) where some scientists are actually trying to measure the size of the universe beyond the observable universe. They do this with some sort of geometry, looking for curvature in triangles between the most distant reference points possible i.e the microwave background. They come to the conclusion that the universe is infinite (or just so big that curvature was undetectable), but I really don't understand what they've actually done.



The explanation given seems kind of simplified, with not much detail on what they were actually measuring or how they were trying to detect curvature. But I don't even understand the geometry of it. In what way would they expect to see curvature? If they're looking directly at the other points then obviously it's going to be straight lines, isn't it?

I had always got the impression that, assuming the universe was curved, that the curvature would be in another dimension. Is that what they're checking for here?

If anyone can give a more thorough explanation, I'd really appreciate it.

[Gawdzilla Sama]

It's big enough for all your stuff.

[Rum]

It's fuckn' HUGE!

[Gawdzilla Sama]

Almost Douglas Adams huge.

[Audley Strange]

Not having watched horizon I cannot say what they were on about. However from what I'm aware of the curvature represents the gravity field and by measuring a proportion of that curve they could calculate it's distance from the plane which would then give distance to perimeters of space/time.

A bit light light curving round our atmosphere, we can measure the curve to find out how photons are slowed and bent.

The thing is that this "curvature" seems to be so huge as to be neglible. Given that and that some think our cosmos is only part of a multi-dimensional froth of multiple domains, the universe is always going to be infinite.

[FBM]

I've been driving for over 30 years and I still haven't found the end.