Atheist

[siti]

Nuff said

Clearly not! Though I do agree it is nothing to do with atheism. But all that apart, I am still trying to get what it is that is measured to 5dp to establish the flatness of the universe - and the supplementary question - that means flatness in how many dimensions? Clearly, 4d spacetime is not flat - and all the illustrations you have provided so far are 2-dimensional surfaces aren't they? - as is @Polymath257 's triangle on the surface of a cylinder. So OK - I can grasp that one might prove that we are - in fact - observing the universe across flat (rather than curved) n-dimensional planes - and that this means we would never - no matter how long we we kept going - get back to the same place if we keep going in one direction - but that could just as easily be true even if the universe has a boundary - couldn't it? (I might not be well up on modern cosmology, but I am at least as up to date as Archytas). It really means that universe is potentially, rather than actually, infinite - doesn't it? Assuming that whatever 'n' is used is the right 'n'? OK - so I've probably committed a dozen misconceptions to writing in this post - I'll stop and wait for more knowledgeable input at this point (not there really are any 'points' - if you get my point).

 

[Polymath257]

So assuming a.multiverse, where are the other universes?

That very much depends on *which* multiverse model you are using. The Everett style has all existing along side each other simultaneously and in the same location (it is quantum mechanical, though). Others have an infinite space that has a type of hyperinflation with regions that are flat and don't expand as fast. Still others have 'infinite' universes pinching off the overall multiverse.

 

[ChristineM]

Clearly not! Though I do agree it is nothing to do with atheism. But all that apart, I am still trying to get what it is that is measured to 5dp to establish the flatness of the universe - and the supplementary question - that means flatness in how many dimensions? Clearly, 4d spacetime is not flat - and all the illustrations you have provided so far are 2-dimensional surfaces aren't they? - as is @Polymath257 's triangle on the surface of a cylinder. So OK - I can grasp that one might prove that we are - in fact - observing the universe across flat (rather than curved) n-dimensional planes - and that this means we would never - no matter how long we we kept going - get back to the same place if we keep going in one direction - but that could just as easily be true even if the universe has a boundary - couldn't it? (I might not be well up on modern cosmology, but I am at least as up to date as Archytas). It really means that universe is potentially, rather than actually, infinite - doesn't it? Assuming that whatever 'n' is used is the right 'n'? OK - so I've probably committed a dozen misconceptions to writing in this post - I'll stop and wait for more knowledgeable input at this point (not there really are any 'points' - if you get my point).

How was it measured? The CMB is 360 degrees, two arbitrary points are chosen on the CMB the angle of each point from an observer on earths viewpoint is precisely known. The observer becomes the 3rd point, he will precisely measure the angle between the 2 points.

Simple addition sums the 3 angles to 180.00000 degrees.

This can be done in any dimensional plane from any point on or close to earth the same result so being a 2d triangle makes no difference.

 

[ChristineM]

That very much depends on *which* multiverse model you are using. The Everett style has all existing along side each other simultaneously and in the same location (it is quantum mechanical, though). Others have an infinite space that has a type of hyperinflation with regions that are flat and don't expand as fast. Still others have 'infinite' universes pinching off the overall multiverse.

So the answer to what our universe is expanding in to is really unknown but has more hypothesis than universe models. ;-)