You people are making my head hurt Stop making me think so hard

Still, I figured we'd had enough debates along these lines recently and decided it'd be more fun just to "roll with it."

I'm glad to hear it. If this sort of untestable "science" had turned up in a certain other thread, it would have put a big hole in my (and, frankly, Karl Popper's) exposition of science as being all about demonstrability and falsifiability...

I hadn't heard the result mentioned in the article, that microwave anisotropy statistics rule out a closed spherical universe -- I thought this was still a very contested issue. And there's a big step between ruling out closed spherical, and ruling in infinite. But anyone whose head isn't messed-up enough by this yet should go and read Borges' The Library Of Babel, which was written (I think) during an earlier period when science suspected the universe of being infinite.

Peter

I hadn't heard the result mentioned in the article, that microwave anisotropy statistics rule out a closed spherical universe

My limited understanding was that the microwave stats ruled out a closed universe of any topology. But I could be wrong.

My limited understanding was that the microwave stats ruled out a closed universe of any topology. But I could be wrong.

Have you got a reference? I'm annoyed to have completely missed a result of this import...

Peter

I don't remember where the theory was from, but I remember my junior year in high school someone proposed a theory that the universe was finite, but looked infinite because it exists in the shape of a mobius strip. I know that made my head hurt at the time.

Sort of like Combat.

it would have put a big hole in my (and, frankly, Karl Popper's) exposition of science as being all about demonstrability and falsifiability...

I disagree, I think it's a great example. Here is a pure theory, it's got ideas that are mostly untestable. Astrophysics and particle physics are at the bleeding edge of our learning, and have many facets which are untestable. We're working toward ways of testing many of these things, but until we do, it's still theoretical if it hasn't been tested. We've never sent a probe to the edge of a black hole and observed what it's like, we can only theorize that a black hole exists because of the x-ray radiation emitted near its event horizon. We can observe with a spectrometer that the universe is expanding, but can only guess as to why or when the expansion started.

It's very important to understand that some theories are more theoretical than others, and this is the root of what science is about. A discussion like this is a great example. You can't put finite vs. infinite universe theories into the same boat as things that are testable like elementary biology. They're both science, and they both can be proven wrong and thrown out if we find evidence which contradicts the theory, it's just that one of them's got a lot more evidence backing it up than the other.

My limited understanding was that the microwave stats ruled out a closed universe of any topology. But I could be wrong.

Have you got a reference? I'm annoyed to have completely missed a result of this import...

Okay, I'm obviously not an astrophysicist, and my knowledge of this stuff is far from expansive, so I may be (read: ``probably am'') misinterpreting this, but, from http://www.discover.com/mar_01/featdark.html:

Recent studies of microwave background radiation had hinted that the universe is flat. But last spring, data from balloon-borne instruments lofted over Texas and Antarctica supplied convincing evidence. Minute fluctuations in the radiation were the expected size. The most precise measurements available revealed that the shape of the universe is flat; it has the critical density and omega equals one.

My understanding is that the universe would have to be closed for it to be finite. Then again, my understanding is that would imply a spheroid universe, yet I've also heard theories of a toroidal or moebius-like universe. I don't know how to rectify all that information. Regardless, I'm pretty sure that flat is flat. But I could be wrong.

Also check out the press release for the balloon experiment mentioned, MAXIMA. Apparently there was another one called BOOMERANG, too.