Shape of Universe

[efanton]

Wow, thats a serious bit of software.

 

Thanks for posting the Vid. From what they mapped it does appear that the universe is spherial and that you get a good idea of where our galaxy the milky way is situated in relation to others. I will keep my eyes open for updates on this.

 

Thanks for the link, better than what I was expecting.

 

the software can be downlloaded here

http://www.amnh.org/our-research/hayden-planetarium/hayden-planetarium-promos/download-files

[Chrispen Evan]

What I am looking for is the actual phyiscal shape of the universe not the theoretical shape.

 

the shape of the observable universe is spherical. the universe that this bit is embedded in has no boundary so has no "shape".

[efanton]

the shape of the observable universe is spherical. the universe that this bit is embedded in has no boundary so has no "shape".

 

The universe is expanding and by definition must have boundaries.

Otherwise the Universe would be infinite and therefore incapable of expanding.

 

Agreed what is observable is not the limit of the univserse, but within that visible limit it might be possible to decern the physical shape of the universe.

[Chrispen Evan]

The universe is expanding and by definition must have boundaries.

 

the universe, the big one not just the observable, according to theory, doesn't have a boundary. this would imply that there is an "outside". for example, and as much as i dislike the balloon analogy, a balloons suface when being inflated gets larger but has no boundary. we must be careful to consider only the surface.

[MigL]

Is that so, Efanton ?

 

Consider the set of real numbers extending to infinity. Now consider a second set of only even numbers also extending to infinity. Each number from the first set can be placed in a one-to-one correspondence with a number from the second set, ie second set members are first set members doubled. Both sets are by definition infinite, yet the second set has doubled the spacing between members, ie it has expanded by two.

 

Your notion of infinity and its consequences is flawed.

[EdEarl]

My feeble brain is befuddled by the idea of infinity and gods. Just because I can consider whether a god or gods exist neither confirms nor denies their existence. Just because I can think of doubling an infinite set of integers, does not confirm that the set of infinite numbers actually doubled or not. Do alternate universes branch off from ours as we encounter alternatives in our lives. Do numbers only exist when someone thinks of them or do they always exist. How many angles can dance on the head of a pin?

 

Forgive my babble, I think I'll move on to a subject that is easier to resolve...maybe climate change.

[efanton]

the universe, the big one not just the observable, according to theory, doesn't have a boundary. this would imply that there is an "outside". for example, and as much as i dislike the balloon analogy, a balloons suface when being inflated gets larger but has no boundary. we must be careful to consider only the surface.

 

But you are wrong. A balloons surface has an area which can be measured and therfore can be considered bounded.

Now I would agree that a path across that surface is effectively infinite.

 

As I understand the big bang theory space and therfore the universe is being created as iflation continues.

The universe cannot be infinite unless you wish to discount totally Alan Guth's theory of inflation as with inflation space, time and the universe are growing. Something thats growing cannot be infinite.

[pwagen]

 

But you are wrong. A balloons surface has an area which can be measured and therfore can be considered bounded.

Now I would agree that a path across that surface is effectively infinite.

 

In 3D, the balloon has a measurable bound. But as a 2D area, the surface does not. Yet it increases in size if the balloon is inflated. Why can't this be translated into our 3D universe, which would then be boundless yet able to increase in size?

[MigL]

Wether finite or infinite we have to assume the universe is unbounded. This is simple to see in the case of an infinite universe as no boundary or 'edge' would ever be reached. A finite universe without a boundary or 'edge' on the other hand, would have to close in on itself. This is easy to picture in the case of a 2D surface embedded in 3 dimensions, such as a sphere, but I assure you it is possible in higher dimensions without embedding.

 

The reason for the unbounded nature of the universe is, of course, to avoid explaning what's on the other side of the boundary, and if you can keep going, is it an actual boundary or just another part of the universe ?

[SamBridge]

There's different models for shapes of the universe. Currently cosmologists most likely suspect it is merely an indefinitely large flat plane due to no measurements of any visible boundary as well as an inconsistent and nearly immeasurable curvature that so far suggests the observable universe does not close back in on itself in a relative 5 dimensional sphere shape or saddle shape. Theoretically, if the universe is a single bubble of existence, there cannot be anything outside of it by it's own definition, so there must be either a closure or it is infinitely large, and it looks like we have more evidence against it being closed.

Perhaps the infinitely large property would explain why we see the universe bigger than it should be if our age for it is correct, or how it could have "expanded" faster than light. Of course the spherical model offers a much simpler explanation for this expansion, but as I said before we just can't seem to find any evidence of any curvature.

Edited June 11, 2013 by SamBridge

[BrightQuark]

Travelling over the flat-plane of the universe is one of most difficult concepts to conceive, well for me at least, because you naturally begin to add in dimensions, if you pass over a surface, and ask - but what is above, why can't you penetrate it, and go straight down and through it, we seem to be limited by our ability to visualise in only 1, 2 or 3D perhaps?

 

Enjoyed watching the TED lectures in here.

Edited June 27, 2013 by BrightQuark