What shape is the Universe?

Factual Questions
1

If the universe has a shape, what is it?
Why?
Help…
I’m drowning in my own cranial plasma.

2

No one knows for sure, and it’s a large topic. (Well, of course it’s a large topic, it’s the Universe!) Briefly, there are only a few models under consideration as possible (and I’ll use descriptors of two dimensional surfaces, because they’re easier to imagine than three dimensional objects):

  • Infinite and unbounded: like a geometric plane, just extending forever in all directions
  • Finite and bounded and oriented (sphere): for two dimensions, think of a sphere or globe – a two-dimensional bug travelling in one direction will eventually wind up where he started from.
  • Finite and bounded but unoriented (Moebius strip) – if you don’t know what it is, forget it, but the idea is that if you travel around the universe in a “straight” (geodesic) line, you wind up back where you started but with right/left reversed.

Then, you add to that, the question of the expansion of the universe (regardless of its shape):

  • expanding forever, without limit
  • expanding until it hits a maximum dispersion and then stabilizing
  • expanding until it hits a maximum dispersion and then collapsing

That about summarizes it, I think, except for the people who think the universe is shaped like a film strip, with separate (parallel) universes on each slot.

But the bottom line at the moment is that no one knows for sure.

3

Some think the universe is curved. I think it’s totally bent! :slight_smile: :slight_smile:

4

I personally have no idea. The Scientologists do though. Seeing as how the evil interstellar overlord won the universe in which we live and was then able to cram it into a jar. The universe must be cylindrical. However, you must take into account that it came from the Bjork galaxy on the back of the omnipotent pet jackass Henry. So the contents may have shifted a little on the ride there leaving it in any possible shape. So I guess the Scientologists can’t explain it then. Oh well.

(If I have offended any Scientologists in my postings I am truly sorry. I am after all just kidding, but seriously, get a real religion for God’s sake.)

Za’an kho’ku na tenshi no teeze. Kyoko Baby!

5

It’s shaped like a really big dough-nut.

6

It’s an oblique rhombus. I though everyone knew that ;).

“I had a feeling that in Hell there would be mushrooms.” -The Secret of Monkey Island

7

I kind of approached this topic in the “Is the Universe Shrinking” thread, which you may want to refer to. I was wondering what was beyond the “edge” of the universe. Nickrz recommended some very good resources which of course, I haven’t bothered to read or even look for yet. If I understand his post (I don’t but if I did…) the universe can’t really have a shape. If it does, I’d like to resubmit my original question.

8

There is no edge of the universe. The image of the universe as an expanding balloon is meant to be taken as what a 2D universe would look like viewed from a 3D vantage point. The image of an expanding 3D sphere is easier for some people to visualize than the image of an expanding (4D) hyper-sphere. You must be careful with the image, however. There is nothing inside or outside the (hyper-)sphere. If you were a two dimensional creature on the surface of a sphere, you would go off in any direction without coming to the edge. For creatures in the universe there is no inside, outside, or edge to the universe.

I would also like to note that the sphere and the plane are not the only two shapes that the universe could have.

Virtually yours,

I J Matrix
“Lies, lies, lies, spam and lies” - Konrad

9

No, no. A hypersphere has a positive curvation, i.e., convex (there are extra points squeezed in between all the regular Euclidian hypercubic spatial points). The universe is a hyperhyperbola with a negative curvation, i.e., concave (there are points missing in between the regular Euclidian hypercubic spatial points).

Here’s a way to visualize it: Take a map and lie it out on a table on a flexible piece of plastic. Grab the top and bottom (north and south) and pull up, curving the map so that any longitudinal line is a hyperbola rising off the table.

Now, grab the east and west sides and bend them downward so that any latitudinal line is a hyperbola that extends down below the table.

Your map should be the shape of a horse saddle. It can continue in all directions infinitely without curving in on itself.

Now do the same thing again, but instead of doing it to a map, you do it to a four inch slab of gelatin with raisins. As you bend the sides up and down into their hyperbolas, you will notice the raisins getting a little bit closer to each other because you’re compressing space. That’s space with a negative curve. That’s home.

Empirical proof? In a negatively curved space, the three angles of a triangle always equal less than 180[sup]o[/sup], and that’s what’s been measured. (In positively curved space, the angles are always more than 180, and in Euclidian space, they = 180).

Now that you have the saddle shaped hyperhyperbolic space in your mind, now picture it expanding. Wow.

Peace.
Peace.

10

Does somebody claim to have made this measurement in our universe? How would it be done?

11

The question of wheither the universe is positively curved as a sphere, negativly curved as a saddle, or flat is still open. Near massive objects the curvature is negative, but overall space appears flat or very nearly so. If the total mass of the universe is less than some critical value then space is negatively curved or open. Above the critical value space curves in on itself and has positive curvature or is said to be closed. At the critical value it would have no curvature or is flat. A closed universe is finite but unbounded. Open and flat cases are infinite and unbounded.

12

The Universe is a very puzzling place (VERY puzzling from what I’ve read here). Although there are some interesting ideas about the SHAPE of the universe, it is only possible for an object existing in 3-dimentional space to have shape (as we perceive it).

If the Universe is expanding, however, and hypothetically it is expanding into nothingness, then it has no shape as nothing must be a zero dimensional entity occupying no space in any dimension.

Also, the ‘interior’ of the Universe is not merely 4-dimentional as is believed by a great many people, but a growing number of physicists and astronomers (including lots here as I have seen) are beginning to accept that it is necessary for the Universe to be TEN dimensional in order to properly explain the phenomena that surround us (like light, gravity, magnetic fields etc.). Therefore, if the Universe consists of 3 spatial dimensions, 1 temporal dimension, and 6 other dimensions then it’s ‘shape’ would be so obscure that it would be impossible for the human mind to conceive it.

That’s what I think, anyway…

“Now be quiet before I rather clumsily knight you with this meat cleaver” - Edmund Blackadder

13

I believe it was the great philosopher Groucho Marx who, when asked “what shape is the world”, did reply “terrible”

I’ll be there
Where I’ll teach what I’ve been taught
And I’ve been taught…

14

I vote for a triskaidekahedron.

15

I’m sorry, a regular triskaidekahedron.

16

Quote:
I’m sorry, a regular triskaidekahedron.

What the hell IS a regular triskaidekahedron (if it even exists), much less an irregular one???

“Now be quiet before I rather clumsily knight you with this meat cleaver” - Edmund Blackadder

17

Pretty bad, but reparable. Now, here’s a detailed estimate…sign right here, please. :wink:

18

LOL, Polycarp

19

moriah said:
Empirical proof? In a negatively curved space, the three angles of a triangle always equal less than 180o, and that’s what’s been measured.

I second AuraSeer: What are you referring to here? I’ve come across the other references in this thread in my (albeit limited) reading on the subject. This is a doozy-- where does it come from? I’d be interested in reading further.

Thanks in advance.

Never murder a man when he’s busy committing suicide.

  • Woodrow Wilson
20

Sorry, BIGmatt, it’s a joke. There is no such thing as a regular triskaidecahedron (a solid with 13 identical faces) in 3D. Plato proved long ago that there are only 5 regular polyhedra: the tetrahedron, the cube, the octahedron, the dodecahedron, and the icosahedron.

TheDude