Is the Universe Shaped Like a Funnel?

DrMorpheus writes "A new theory of the shape of the Cosmos posits that the Universe may be shaped like a medieval horn, according to Frank Steiner at the University of Ulm. This theory, if true, could explain several strange observations about the microwave background radiation. The Universe would be stretched out at one end into a long tube and flared out into a bell at the opposite end. The technical name for this shape is a 'Picard topology'. To quote the article, '...our Universe is curved like a Pringle, shaped like a horn, and named after a Star Trek character. You could not make it up.'"

Comments

Of course, Monty Python reference.

[The I Shing]

I just have to jump in and be the first one to make the reference to Sir Bedevere's remark at the end of what could only be assumed to be a lengthy explanation to King Arthur, "...and that, my Liege, is how we know the earth to be banana shaped."

Imagine if he'd said, "...and that, my Liege, is how we know the universe to be shaped like a trumpet." Terry Gilliam and Terry Jones might have been Nobel Prize candidates.

Re:Of course, Monty Python reference.

[fshalor]

Maybe that's why music soothes the soul. I mean, if the whole universe has the shape of a sound producing "horn".. (I know, the subject said "funnel" but the body says "horn" and I'm a brass player)

My only next question is has anyone determined the resonant frequency set fot it? It's have to be almost imperceptable in the low end. Jeeze. We're talking about pico Hz here.

Wasn't discovered a few years ago that there was a prevailing low Bb (lots of octaves below the tuba range) sounding through the universe?

"Good Night..." dingdingdingdingding

Re:Of course, Monty Python reference.

[Warpedcow]

Wasn't discovered a few years ago that there was a prevailing low Bb (lots of octaves below the tuba range) sounding through the universe?

Many electronic appliances and lights give off a very low db B-flat hum (at least in the US) because of the 60hz frequency in the electricity here (60hz = Bb). I suppose in Europe it's a different pitch (50hz).

Anyway, because of this constant Bb that we're all subconsciously bombarded with, most people, when asked to hum ANY pitch, will hum a Bb!! (Learned this in a music class at college)

Re:Of course, Monty Python reference.

[ThosLives]

The interesting thing is that in the US things are emitting tones at 120 Hz, not 60. (however, there is a Bb at ~116Hz and a B at ~123 Hz, so calling this a Bb is still pretty close). Since the current reverses direction *twice* per cycle, metal in transformers, etc. expands and contracts *twice* per cycle, generating sound at twice the current frequency. For more information, see this link on magnetostriction

Re:Of course, Monty Python reference.

[Mateito]

> Maybe that's why music soothes the soul. I mean,
> if the whole universe has the shape of a sound
> producing "horn".. (I know, the subject said
> "funnel" but the body says "horn" and I'm a
> brass player)

I am also a brass player*. But that doesn't stop me imagining that the Universe is the shape of an erect penis.

Adds a whole new meaning to the "big bang".

Also explains what the unverse was created in 7 seconds.

*Technically not, I play Sax, which any Trumpet playing purist well tell you is a woodwind instrument, even though its not made out of wood.

Re:Of course, Monty Python reference.

[Xilman]

such a calculation would be meaningless. whereas the space inside an instrument horn is filled with air and is where the sound comes from, the "space" in the model-universe horn is completely unaccessible.

Not entirely. The universe may be empty to a good approximation, that doesn't mean that it can't support standing waves.

Spacetime itself is elastic (assuming that you believe in General Relativity or something similar to GR) and so can distort in a periodic manner. These distortions are called gravity waves and there's some indirect evidence that they exist. Searches for direct evidence are underway.

Similarly, any other long-range field can support standing waves. I see no a priori reason why electromagnetic waves can not exist which have wavelengths which are integral fractions of twice the universal scale.

Likewise, I can see no a priori reason why any of the possible standing waves should not have observable consequences.

Paul

Re:Of course, Monty Python reference.

[red floyd]

When you double the frequency, it's the same note - just one octave higher.

i.e. if 60Hz is Bb, so is 120, 240, 480, etc....

Re:Of course, Monty Python reference.

[Anonymous Coward]

>My only next question is has anyone determined the resonant frequency set fot it?

42Hz.

Uhm, that explains a lot!

Re:Of course, Monty Python reference.

[The Only Druid]

I'm just asking for an offtopic mod here, but I'd just like to chime in on something:

A sax is a woodwind, as I'm sure you know, because its sound originates in the wooden reed in the mouthpeice (just like other woodwinds like clarinets and oboes, both of whose bodies can be wood, plastic or other materials), whereas all brass instruments have their sound originate in a brass or otherwise metallic mouthpeice.

This is the same reason that a piano is considered a string instrument (since the sound originates in the vibrating string) as opposed to a percussion instrument (due to the hammers inside that hit the strings) even though it mechanically seems similar to the xylophone.

Re:Of course, Monty Python reference.

[fatphil]

Close, but no cigar.

It's 120Hz in the US, and 100Hz in Europe.
The sound is based on the _amplitude_ of the signal, and there are two peaks and two zeroes for each cycle, hence the hum has twice the frequency of the mains source.

Ask any geeky guitarist/bassist.

FP.

Re:Of course, Monty Python reference.

[seanmeister]

Back in the navy, I spent many-a-midwatch on an aircraft carrier standing next to 60Hz, 4160V power panels, playing slow harmonica melodies on top of that 60Hz hum. :-)

Re:Of course, Monty Python reference.

[nexthec]

still wrong, but closer with the 120 Hz, at 60 Hz most people have hard time hearing the sound. The noise is created by the real power (p=v*i) the multiplication of the voltage and the current both 60 Hz waveforms. When you multiply two sine waves together you get a doulble frequency and a half frequency component. That is what you are hearing

Re:Of course, Monty Python reference.

[DavidTC]

Sound waves are displacement of matter, not just air.

Re:Of course, Monty Python reference.

[C0rinthian]

*Technically not, I play Sax, which any Trumpet playing purist well tell you is a woodwind instrument, even though its not made out of wood.

And they would be right, as a piece of wood (the reed) is what produces sound. The saxophone itself (metal) is simply an amplifier. (albiet an amplifier that alters pitch and refines tone)

What shap haven't we had

[twanvl]

Last year it was a dodecahedron, this year a funnel, what's it going to be next year?

Re:What shap haven't we had

[mog007]

Next year the scientists of the world will get together, and agree that the Universe was created from a giant sneeze, BEWARE THE COMING OF THE GIANT WHITE HANKEY!

Re:What shap haven't we had

[Ralph Wiggam]

Something else that makes no sense but is going to get someone a research grant.

-B

Re:What shap haven't we had

[maxwell demon]

I've got the solution:

The universe is universe-shaped!

Re:What shap haven't we had

[divisionbyzero]

A Klein bottle? If you took the end of the funnel and passed it back through itself it would look just like a klein bottle:
http://mathworld.wolfram.com/KleinBottle. html

Re:What shap haven't we had

[buckeyeguy]

An hourglass... two funnels connected together.

Re:What shap haven't we had

[SmackCrackandPot]

From Professor Simpson on donutology

Donuts most definitely. There are two things to note. The first is that we don't know what's at the end of the horn. For all we know, there could be another horn facing in the exact opposite direction. The other is that we don't know what's outside the open end either. But it must wrap around and go somewhere. If there are two horns end-to-end and they wrap-around, you've got a bagel or donut depending on what's filling the universe. Then the galaxies are like raisins in a raisin donut, and the remnants of the big bang are like the icing on the top of the donut or sesame seeds on the top of a bagel. Either way the universe is a yummy place to be.

Re:What shap haven't we had

[Rufus88]

Future headlines:

"Soccer balls are universe-shaped!"
"Funnels are universe-shaped!"
"Scientists believe waffle-fries are universe-shaped!"

Someone enlighten me....

[rdsmith4]

How can the universe, the sum of everything which exists, have shape? What, then, is outside this funnel? Isn't it infinitely large by definition?

Re:Someone enlighten me....

[Linux-based-robots]

I assume by shape scientists mean the curvature of the space-time topology, outside of which nothing exists. Kinda like a quake map, where you turn off clipping and go outside of it nothing exists but you can still say what the map is "shaped" like.

Re:Someone enlighten me....

[harks]

From what I've read, the universe is in three dimensions what the earth is in two: It is finite in size but has no boundary. Going in one direction long enough will bring you back to where you started.

Re:Someone enlighten me....

[GuyinVA]

I thought the same thing. I think this was theorized by someone looking to make theories.

If there is a finite line between the universe and whatever else is out there, what is it's shape?

Re:Someone enlighten me....

[cybermace5]

How can the universe, the sum of everything which exists, have shape? What, then, is outside this funnel? Isn't it infinitely large by definition?

It might be seemingly infinite in three dimensions, but imagine two-dimenional topology mapped onto a ball. You could go seemingly infinitely in a single direction. Yet the ball has a finite volume. Now apply this to dimension over three....

As for what's outside the universe, there can be only one answer:

Lost socks.

Re:Someone enlighten me....

[Torgo's Pizza]

So that big old guy dressed in white with the beard turned on "God" mode? It's all beginning to make sense now...

Re:Someone enlighten me....

[hcg50a]

"What is the universe" and "What is the shape of the universe" are two different questions.

I don't think the universe being discussed is "everything that exists".

The shape being discussed is more technically the shape (or topological character) of the geometry of the universe we find ourselves in.

There are many kinds of shapes that are possible, some "space filling" and some not. (I am sure there is a more correct technical term from topology to describe "space filling".)

The question of shape does not address what's in the gaps if it's not space-filling.

In the Star Trek, Euclidean world, the universe is flat, the speed of light appears to be essentially infinite and there is also no physical limit to speed, and simultaneity holds.

This is clearly not the case in our universe, and locally, it's not even flat, but positively curved.

The overally curvature has been debated ever since Einstein released General Relativity, and the answer seems to vacillate between flat and negatively curved.

The article is discussing the simplest kind of negative curvature, but it is taking the discussion to extremes that I have not seen discussed before.

The trumpet shape being discussed is a two-dimensional analog of the actual case in our universe, and is clearly not space-filling.

Re:Someone enlighten me....

[IndependentVik]

We may just be in some huge omniscient being's snow-globe paperweight sitting on a stack of his tax papers.

Well, jeez, if an omniscent being can't get out of taxes, I guess the rest of us schmoes don't have a chance :(

Re:Someone enlighten me....

[NoMoreNicksLeft]

So, to build a time machine capable of traveling into the past, I need only surround the "vehicle" with an incredible mass worth of unmated socks?

Is it dangerous, do I risk tearing a hole in the very fabric of spacetime itself?

Re:Someone enlighten me....

[dcsmith]

For enlightenment, please read Flatland by Edwin A. Abbott. A very interesting way to conceptualize life in one, two and four-dimensional worlds.

Re:Someone enlighten me....

[stevelinton]

You can determine the "shape" of a piece of space from inside it. Let me drop down one dimension and consider the shapes of surfaces. We all know that the angles at the corners of a triangle add up to 180 degreed. This, however is only actually true, when you draw your triangle on a truly flat surface. On a curved surface such as that of the Earth, the angles will add up to MORE THAN 180 degrees. Consider, for example a triangle with one vertex at the N pole, and two 90 degrees apart on the equator, with its edges made of great circles (the appropriate analogue of a straight line). All THREE angles of this triangle are right angles.

In fact, on a sphere of radius R, the sum of the angles exceeds 180 degrees by 180/pi * A/r^2, where A is the area of the triangle.

On a saddle-shaped surface, the angles of a triangle are always LESS THAN 180 degrees in a similar way.

Building on these ideas, you can define a precise notion of the shape of a surface entirely from INSIDE the surface, and extend it up to three dimensions (or more) dimensions. This is what the cosmologists are talking about when they talk about the "shape" of the universe.

Re:Someone enlighten me....

[call -151]

A good parallel to understand is if you were an ant living on the surface of a basketball. Your travels can go in any direction at any point, as if you were on a plane. If you had no memory, you may not noticed that when you travelled you were visiting places you had already been and you might think that you lived on a plane. In fact, the outside observer can see that your universe is curved.

If you haven't read Flatland it is a gem that illustrates these notions of higher-dimenstional space wonderfully. It was written in 1888 and is in the public domain now, availble free online through Project Gutenberg or for a buck or two as a physical book.

A wonderfully-done video is The Shape of Space, produced at the Geometry Center and uses nice animations to make these points. If you haven't see the Shape of Space or two of its Geometry Center sibling videos (Not Knot and Inside Out) you are seriously missing out.

Re:Someone enlighten me....

[SilverSun]

I don't think the universe being discussed is "everything that exists".

Oh yes, that's what they talk about indeed.

..some "space filling" and some not..

No, there is no "space outside the universe" that
migt get filled. It is a question of space-time
"curvature". A manifold does not need to be embeded
in a higher dimensional space to have a curvature.

The question of shape does not address what's in the gaps if it's not space-filling.

there are no "gaps"

The article is discussing the simplest kind of negative curvature

...which is still possible in the light of WMAP
measurements. The simplest form of negative
curvature is the "pringle" (or more common: "saddle")

The trumpet shape being discussed is a two-dimensional analog of the actual case in our universe, and is clearly not space-filling.

because it is a two-dimensional shape embeded in
a three-dimensional space. The universe, i.e. space-time is (most likely) not embeded in a higher dimensional space. (That is even true if
your name is Witten and your space-time has 11 dimensions, still, it is not embeded somewhere)

Cheers

Re:Someone enlighten me....

[PetWolverine]

To make this explanation less confusing, you might say the Universe is in three dimensions what the Earth's surface is in two. I don't mean to be a pedant, it's just your explanation might not have made sense to someone unfamiliar with the idea, since the Earth is a three-dimensional object.

Re:Someone enlighten me....

[lildogie]

Basically, the shape of the universe determines what happens to "parallel" lines as they stretch across huge distances.

The universe is not infinitely large by definition. General relativity describes how the size and age of the universe are related and quite possibly finite. This relates to the "big bang" and the question of whether it will be followed by a "big crunch."

Inside and outside are terms that only have meaning when you divide the universe into parts. When talking about the universe, as you point out, there is no sense in speaking of that which is "outside."

Now, write a book.

Re:Someone enlighten me....

[ph43thon]

But when you are making your triangle on the surface of the earth, you know where to place the vertices. Just put them on the ground. "Where" do we "place" the "vertices" of the "triangle" in our Universe? Or, what other technique would we use? As it stands now, don't they just look for repeating patches of background radiation and things like unexpected shapes of galaxies?

Also, how does a being in a 2-D world measure the angles? The best I can figure is by using time, but we just do it by stepping back and looking down from the next dimension up where we can compare ratios and thingies.

p

Re:Someone enlighten me....

[Eil]

Or, in other words, space is curved.

Re:Someone enlighten me....

[tyler_larson]

By and large, science is all about making conclusions about what something is by observing how it behaves.

Whether or not the universe actually is curved or flat or banana-shaped is really immaterial. All we really care about is what we can observe, and more importantly, what we can expect to observe in the future. If rules and laws and principles we come up with accurately predict how objects, forces, etc. will interact in the future, then those laws are "correct" as far as we know and as far as we care. Newton's laws of motion and Einstein's laws of relativity are both considered "correct" even though they contradict eachother. They're correct because they can be used to accurately predict the future.

After all, when you drawing out your calculations for how to send a monkey to Mars, it really doesn't matter what shape the universe is if you know for certain that it at least behaves as if its shaped like a donut. Your donut-based calculations will still get chimpy to Mars--and it's the results you're after.

As our perception increases, we notice that our existing models do not adequately describe the reality we observe. So we come up with another (probably much more odd) model that describes the results we see, but that still agrees with the results we've previously attributed to the old model. The new model is considered "correct" and the old model is still considered useful.

Re:Someone enlighten me....

[serano]

To make this explanation less confusing, you might say the Universe is in three dimensions what the Earth's surface is in two.

This might be getting at what I don't understand. On the surface of a globe, if I travel along the x-axis long enough I come back to where I started. In space though, the surface of the globe does not stop me from going into the volume of the object, so that would imply I could get to a point on the other side of the structure in two ways: either travel along the x-axis long enough or, the quicker route, cut through the middle. Is this correct?

It also seems like if I stand on the surface of the globe and stretch my hands straight up and start flying in that direction, that I would head infinitely away from the globe. That suggests the globe space-topology is itself in a space-topology, because I'm leaving the globe topology behind and entering another space. Is this a logical outcome of the 3-d topology model that's being discussed? If so, how is the infinity problem this implies handeled?

Re:Someone enlighten me....

[The Unabageler]

incorrect. In this analogy you cannot cut through the middle because you are limited to traveling on the surface. When things like this are spoken of, the earth's surface is 2 dimensions only, you cannot leave the spherical plane into a third dimension. Likewise, with the 3d universe as the surface of a 4d sphere, you cannot leave the 3rd dimension and "cut through the middle."

Re:Someone enlighten me....

[SilverSun]

this is an artificial concept brought from mathematics

from math, yes. artificial, no.

I have yet to see an actual demonstration of something been bended without been embedded into space of large dimensions

you can see it everywhere. I'll try to explain
something that would be easy to show in a classroom.

Imagine a piece of cloth lying on a table. the threads from which the cloth was woven define 'straight'. they form rectangular shapes.
Now, draw a triangle on the cloth. if you
add up all the angles, you will get 180 (if you
did draw correctly). Now, let's say the cloth
is a little elastic so that you can strech it
with your hands while it is lying on the table.
With two hands you will stretch the cloth more at
some points and less at others. Now measure and add the angles in your triangle again. The result
will in general be different from 180. if it is
higher than 180 you have created positive curvature, if less, negative. All that while the cloth is still lying flat on the table.

could anyone please present any evidence that there is nothing outside of Universe

I hope you realize yourself, that this is a preposterous demand.

Even if our four known dimensions would be embedded in, say, 11 dimensions
and we just see a brane in this space. The 11-dimensional space would be what we call universe.

Cheers

Re:Someone enlighten me....

[SilverSun]

Then how do you explain that the universe is expanding?

imagine you are an ant standing on an infinite rubber plane. every 2 meter there is a pole. now someone streches the rubber plane. the poles will be farther appart from each other. The plane didn't expand or bend in any other dimension as the two dimensions it already occupies.

Now you are asking "How do you stretch a plane that is already infinite"... errr well... ;-)
After a couple of semester in math your brain is so fried that you don't try to think about that ;-)

Cheers

Re:Someone enlighten me....

[SilverSun]

Your example with peace of cloth does not hold water because it is clearly embedded into out 3D world.

No it is not. it stays completely in two dimensions. the complete chain of arguments holds in absence of a third dimension. Thus it can be genralized to curved three-dimensonal spaces in absence of a >=four dimensional 'surrounding'

What you fail to realize is, that "curvature" in a mathematical and thus physical/cosmological sense does NOT mean something is "bent". It exclusively means, that the sum of angles in a triangle is tno 180. This and (almost) only that.

Cheers

Re:Someone enlighten me....

[markh1967]

Or read Flatterland " which extends Flatland with more than 100 years of topological research and brings it up to date with present-day thinking.

A fascinating and eye-opening book.

If it is shaped like a funnel

[Tibor the Hun]

If it is shaped like a funnel, does it point up -- like a Dunce Hat, or down -- like a toilet bowl?

Um

[Anonymous Coward]

...our Universe is

As opposed to the other universe that somebody else owns.

Re:Um

[spellraiser]

Sorry - I just have to cut in here.

It's actually our universe. The rest of you will need to pay $699 to live in it.

- Darl McBride

Picard topology

[dmccarty]

Does that have something to do with the shape of Patrick Stewart's bald head?

Called Pringle. ..

[Anonymous Coward]

I guess this gives a whole new meaning to the words "Big Crunch".

Picard topology?

[KevinKnSC]

Clearly, what the universe needs is an Elizabethan adventure on the holodeck!

cool, duuuude

[WormholeFiend]

more stuff to ponder during stoner trips...

"hey man, did you know the whole universe is shaped like my bong?"

"no waaaaaaaaay! does that mean you could use it to get high?"

The Picard Topology

[base_chakra]

...is of course named for the pointy hats Picard used to wear to crack up Wharf.

Well then

[FS1]

If the universe is shaped like a horn, curved like a pringle, and named after Jean-Luke Picard.
Then it is all my favorites rolled into one.
The universe blows, is made out of mashed potatoes, and is named after someone i look up to.

Sorry couldn't help myself.

Re:Well then

[FS1]

Might I suggest that your universe blows because you look up to a Star Trek character?

Not that kind of blow.

Re:Frist psot

[Metryq]

The universe is a music instrument.

Be sure to pull that spit valve once in a while.

And because it is "expanding," it is getting bigger. When the universe reaches the standing wave frequency of the Great Superstring, it will all vibrate apart.

Re:Sounds

[WwWonka]

No, the sounds come from your head being shaped liked a Pringles can and God shaking it looking for those last few elusive chips.

Kirk vs Picard

[CaptnMArk]

Eat your heart out Kirk!

Re:Kirk vs Picard

[Tibor the Hun]

You bring a good point.
No one mentions that the theory was postulated by a relatively unknown graduate student Mr. Khaaan!

Kirk by the way is a much better captain than Piccard. No-nonsense "let's all just get laid" kinda guy.

Re:Kirk vs Picard

[Psmylie]

That entirely depends on your viewpoint... if you want a captain who is very capable and will most likely get you out of any dangerous situation, go with Picard. If you want a "party" captain (bring on the green alien chicks!) go with Kirk. Up to you, really. Kirk is much more likely to throw a ship-wide kegger than Picard, but Picard is a little less likely to make you wear a red shirt, beam you down to an unknown alien world and send you off to investigate behind that big pile of rocks while the officers all chat a safe distance away.

Why Classify?

[Sentosus]

Why do we continue to classify the shape of the Universe? Realistically, if we can not define the shape by placing it within a totally viewable package, it because useless to define it by something that we are unable to classify. Funnel? We see the outside of the funnel so that we can define the shape, but from the interior, it is just a curved or flat plane that we can only recognize by viewing from an all emcompassing view external.

Since we have no proof of anything beyond the Universe, this is just a chasing of a simple definition. Without the Universe in a 3D viewable environment and being just IT, then we can't define the shape meaningfully.

Think of it like this, we could say the work was flat, but it was not till we were able to look at it from an external view. Think being about 4 miles deep in the Earth and attempting to define the shape of the Earth.

Anyway, I shall crawl back in my hole and wait for those much smarter than me to put me in my place. :-P

Re:Why Classify?

[TwistedGreen]

Why couldn't an object have only one side?

Re:Why Classify?

[tommck]

We see the outside of the funnel so that we can define the shape, but from the interior, it is just a curved or flat plane that we can only recognize by viewing from an all emcompassing view external.
...

Without the Universe in a 3D viewable environment and being just IT, then we can't define the shape meaningfully.

Umm... we proved that the world is round based on an "internal" view...

Do you think Ptolemy went up in a space capsule to see the shape of the earth before he told everyone it's round?? In 250 BC, Eratosthenes had calculated the size of the earth to within 10% of its actual size.

None of that was done "externally".

Anyway, I shall crawl back in my hole and wait for those much smarter than me to put me in my place. :-P

I like to think that I did just that ;)

Re:Why Classify?

[theLOUDroom]

Think of it like this, we could say the work was flat, but it was not till we were able to look at it from an external view.

But, that's the thing, scholars knew the earth was round long before were able to see it from space, and long before Colombus made his first voyage. They were able to observe the effects of its shape.
They noticed the horizon, celestial activitiy, etc.

The same types of observations we would use to determine the shape of the universe.

For a geometrical argument:
Say you were able to precisely measure your own motion relitive to a starting point. As you traveled around the earth you would realize you were traveling on a curved surface, and after one trip around the world, you would decide it was a sphere. After two different trips, an oblate spheroid.
At the end of this, you've determined the shape of the earth without ever leaving it.

Re:Why Classify?

[TALlama]

Think of it like this, we could say the work was flat, but it was not till we were able to look at it from an external view.

Ah, that fateful day when Columbus climbed into the Nina, the Pinta, and the Santa Maria and blasted out into orbit to observe the world's shape.*

* Substitute Leif Erikson if you prefer. **
** Substitute Various Mathemeticians if you prefer. ***
*** Substitute Cowboy Neal if you prefer.

Re:Why Classify?

[lone_knight]

Developing a Theory on the shape of the Universe may help explain questions in other Theories, such as "strange background radiation" as mentioned in the original post.

It also helps explain why Captain Picard got laid so often. "Hey, baby, your talkin' to the guy they named the Universe after..."

As to your example about being 4 miles deep in the Earth, even though you may not be able to "see" the outer surface of the planet, you could still use seismic observation to map the size and shape of the earth from the inside. By observing radiation and light-shifts we now have the new and improved "shape of the Universe".

If you still think that knowing the shape of the Universe is useless, men have been searching for useless explanations to equally useless questions since the dawn of man so there should be no surprise there.

Re:Why Classify?

[Anonymous Coward]

Why do we continue to classify the shape of the Universe?

Because knowing more about the universe allows us to narrow down the possibilities of existence. For instance, if this new story is actually the case, it means that the universe is finite. So far there has been no real evidence that the universe is finite, leaving open the possibility that the universe is infinite. (i'm talking the universe here, not just our hubble volume)

If the universe is infinite, you necessarily have an infinite number of identical copies of you, living exactly the same life you are. You can even make a rough estimate about literally how far you are away from your nearest "twin". (s/he is 10^(10^28) metres away from you) Read the article at scientific american. It is online somewhere, but here is the abstract

See how physics is so closely tied to philosophy? That's why physics used to be called "natural philosophy". Knowing more about the universe allows us to...well, know more about the universe, and hence, the philosophical implications.

Knowledge is good.

cheers!

Re:Why Classify?

[bradkittenbrink]

Since we have no proof of anything beyond the Universe, this is just a chasing of a simple definition. Without the Universe in a 3D viewable environment and being just IT, then we can't define the shape meaningfully.

I'm not a mathematician, but my roommate was and he explained this to me once. These descriptions do not require anything beyond the observable universe to exist, they are merely technical statements comparing the characteristics of our universe to a flat euclidean universe, which are conveniently (confusingly) worded to sound like visual descriptions. The statement "the universe is shaped like a funnel" is still meaningful in that sense, even though no one can ever view the universe from the 4 dimensional perspective that would be required to actually see a funnel shape.

Re:Why Classify?

[merlin_jim]

Since we have no proof of anything beyond the Universe, this is just a chasing of a simple definition. Without the Universe in a 3D viewable environment and being just IT, then we can't define the shape meaningfully.

Contrarily, there are simple experiments we can do (and have done) to determine the shape of the universe. For instance, let's assume that you and I are two dimensional creatures living on the surface of a sphere. The sphere is very large, and you and I believe it to be infinite in all directions, and flat. We are in the profession of being surveyors, and we survey a few small triangles. A little known fact is that on the surface of a sphere all triangles have angles that add up to greater than 180 degrees; in fact if you measure a triangle that is proscribed orthogonally, it's angles are 270 degrees; to understand what I mean by orthogonal, I mean a triangle that has as its sides, if we were on the earth, the equator, the prime meridian, and 90 degrees longitude.

As we start measuring larger and larger triangles we find that our error increases more and more until we must assume that something is strange with the shape of our space; this is analguous to what our scientists have done. For more details, I highly recommend Sphereland...

Knowing the shape of the universe can be useful as we search for the Grand Unified Theory - the Theory that unifies gravity with the other fundamental forces, and reconciles macroscopic general relativity with microscopic quantum mechanics, and is therefore able to predict very precisely the outcome of any event at any scale.

By knowing the multi-dimensional topology of the universe, we can determine what the GUT may look like, and we can positively rule out GUT's that don't predict that the universe will have a specific topology that we have measured it to have.

Re:Sounds

[rootofevil]

no, but im sure theres a joke about a horny universe in there somewhere.

Are we inside a black hole?

[SmackCrackandPot]

If you turn the picture sideways, it really looks like the space-time distortion caused by an extremely massive object, like a black hole. This reminds me of the theories that the universe is inside a black hole. The apparent expansion of the universe would be caused by the stretching of the space-time continuum.

So, could you have black holes embedded inside the distorted space of another (huge) black hole (almost fractally?).

Re:Are we inside a black hole?

[Tibor the Hun]

Your theory, while thought-provoking, is totally wrong.
Everyone knows that we are inside a fingernail.

Thank you for your time and efforts.

Out side the horn

[Simon Lyngshede]

Good, now that we got that in place, could someone then please tell me what is outside the horn. I really don't care about the shape of the univers, it could be in the shape of a giant moose for all i care, but I what to know what's outside the univers.

Re:Out side the horn

[maxwell demon]

According to current theory, there is no outside of the universe.

That is, it's not just, that there is nothing outside of the universe, but "outside of the universe" itself doesn't exist.

And of course you have the obligatory Homer quote

[Glamdrlng]

"So we have determined that the universe is actually shaped like a giant cosmic donut."
"Mmmmmmm, universe..."

sceptical about all such theories

[wjzhu]

While I respect all the hardwork at detecting various scientific evidences and dreaming up models to fit the data, there is always the reality that, upon finding a tooth, people will glamorize the whole enterprise by drawing up a whole mammoth, and tell you the entire history of that mammoth and what color its eyes are, ... Then the public will be so enamor with the whole story that they forgot what part is fact, what part is fiction, and what part is marketing techniques.

My God

[BigBadBus]

This explains why the Universe has turned out the way it has - its shaped like a rectum!

Symmetry

[eclectic4]

"At the other end, the horn flares out, but not for ever - if you could fly towards the flared end in a spaceship, at some point you would find yourself flying back in on the other side of the horn."

and... "At an extreme enough point, you would be able to see the back of your own head."

This is an example of symmetry, something that is paramount in keeping when explaining shapes of the Universe. Just had to point this out...

A funnel now?

[FreeLinux]

Slashdot loves these guessing games, doesn't it?

Slashdot says; the universe is shaped like a doughnut
Slashdot says; universe is shaped like a soccer ball

I say; the universe is shaped like a /. Prove me wrong.

Re:A funnel now?

[Feanturi]

The article made me think of this gem:

'Alright,' said Ford, 'imagine this. Right. You get this bath. Right. A large round bath. And it's made of ebony.'
'Where from?' said Arthur, 'Harrods was destroyed by the Vogons.'
'Doesn't matter.'
'So you keep saying.'
'Listen.'
'Alright.'
'You get this bath, see? Imagine you've got this bath. And it's ebony. And it's conical.'
'Conical?' said Arthur, 'What sort of...'
'Shhh!' said Ford. 'It's conical. So what you do is, you see, you fill it with fine white sand, alright? Or sugar. Fine white sand, and/or sugar. Anything. Doesn't matter. Sugar's fine. And when it's full, you pull the plug out... are you listening?'
'I'm listening.'
'You pull the plug out, and it all just twirls away, twirls away you see, out of the plughole.'
'I see.'
'You don't see. You don't see at all. I haven't got to the clever bit yet. You want to hear the clever bit?'
'Tell me the clever bit.'
Ford thought for a moment, trying to remember what the clever bit was.
'The clever bit,' he said, 'is this. You film it happening.'
'Clever,' agreed Arthur.
'You get a movie camera, and you film it happening.'
'Clever.'
'That's not the clever bit. This is the clever bit, I remember now that this is the clever bit. The clever bit is that you then thread the film in the projector... backwards!'
'Backwards?'
'Yes. Threading it backwards is definitely the clever bit. So then, you just sit and watch it, and everything just appears to spiral upwards out of the plughole and fill the bath. See?'
'And that's how the Universe began is it?' said Arthur.
'No,' said Ford, 'but it's a marvelous way to relax.'

mmm, donuts

[gobbo]

Whatever happened to the theory (IANAP) that the universe, at least as described by our limited understanding of dimensions, was shaped like a toroid? I seem to recall this as a popular (as in popular science) theory a decade ago.

At the University of Umm

[stratjakt]

STUDENT: Professor, what is the Universe shaped like?

PROF: Ummm, a big horn. Next question.

STUDENT: Professor, what causes cancer?

PROF: Umm, breadsticks.

STUDENT: Professor, is Linux going to take over the desktop this year?

PROF: Umm, yeah sure.

DONT YOU BELIEVE IT!

Yes, it is.

[wramsdel]

The universe is shaped like a funnel, and my desk would seem to be located at the pointy end.

infinitely long and yet finite volume?

[John_Sauter]

One end is infinitely long, but so narrow that it has a finite volume.

Could someone who is mathematically-inclined help me with this? How can comething be infinitely long in one of its dimensions without having an infinite volume?
John Sauter (J_Sauter@Empire.Net)

Re:infinitely long and yet finite volume?

[call -151]

There are plenty of ways that something can be infinite in extent yet have finite volume. The point that just because you are adding up infinitely many things, you do not necessarily get an infinite sum. For example, 1/2+1/4+1/8+1/16+... is an infinite sum which converges to 1, or a repeating decimal like .33333 can be thought of as 3/10 + 3/100 + 3/1000 + ... which converges to 1/3. For volume, we can imagine a horn-shaped region which gets skinnier as we move along, so the first meter of length may have volume 1/2, the next meter may have volume 1/4, and so on. It will be infinitely long yet have a finite total volume of 1.

There are plenty of examples of phenomena such as this illustrated in a standard calculus text, so you can look for more details there.

Re:infinitely long and yet finite volume?

[maxwell demon]

Well, it's quite easy. Let's go one dimension lower, and think about an in one direction infinitely long strip of paper (like an toilet paper strip that begins somewhere but never ends), which is getting narrower fast enough.

On the first meter, it has, say, an area of one square meter (yes, that's quite large for toilet paper :-)). But since it's getting narrower, on the next meter, it just has an area of 1/2 square meter. On the next meter, it's area is just 1/4 square meter, and so on, on each meter half the area of the previous meter.

Now, how large is the total area? Well, let's look at it (I'm ommiting the square meter unit for brevity):

The first meter has, as I said, an area of 1.
The first 2 meters have an area of 1+1/2 = 1.5.
The first 3 meters have an area of 1+1/2+1/4 = 1.75. ...
The first 10 meters have an area of 1+1/2+...+1/512 = 0.998046875. ...

As you see, as you add up the area meter by meter, the total area gets arbitrary close to 2, without ever reaching it. Therefore the total area is just 2 square meters.

Or to see it differently: When cutting the first meter off, the resulting strip looks exactly the same, just half as narrow. Therefore it has half the area of the original strip, the other half being the cut off first meter, which, as we know, has one square meter. Therefore the whole area is 2 square meters, which clearly is finite.

Re:infinitely long and yet finite volume?

[doublebackslash]

Two words from calc Two: Gaberiel's Horn.
Rotate f(x)=1/x around the y-axis and x between 1 and infinity is the horn. Finite volume (Pi something), infinite surface area. It could never hold enough paint to cover the insidde of the can =).

intuition

[Anonymous Coward]

It is considered more philosophically pleasing for the universe to have finite volume (rather than infinite)?
The concept of a universe with no beginning in time might be un-pleasing because it could mean an infinite amount of time has passed until this moment, which seems absurd. But I don't see any similar paradoxes with infinite volume. Nothing has to travel an infinite distance to get where it is. Nevertheless, it seems the finite volume aspect of this model is one of its proposed selling point. Can anyone explain?

Re:intuition

[PepsiProgrammer]

Infinite time and space produces a parodox, dont remember the name of the parodox at the moment, but basically it goes like this.

If the universe is infinite in size, and has been around infinitely long, then it would stand to reason, that when one looked into the sky, every line of sight in the sky would lead to a distant star that has been around long enough for its light to reach us, and if this were the case we would all fry.

Re:intuition

[WoodenRobot]

Olber's Paradox.

Check out the entry in E2.

It's not necessarily a problem, though and may have various solutions - some of which are mentioned in the write up and the accompanying links. Of course the Big Bang has its own fair share of paradoxes, since it's basically creation ex nihilo. Now that's a philosophical no-no if ever there was one.

Look at the data

[Effugas]

Hmmm. The big bang posits a long period of time where everything is compressed, followed by an explosion which flares stuff out in all directions.

A long thin period, followed by a huge flare...that is sort of the shape of a trumpet. These are the guys who tell us that distance equals time, too...not to pretend to be a cosmologist, but isn't it possible that we're seeing a trumpet shaped universe because our input data (i.e. energy) followed a trumpet-shaped distribution curve over time?

Re:Look at the data

[Surazal]

Not quite... they're talking in strictly spacial terms. When they say the Universe is shaped like a trumpet, they mean literally like a trumpet.

Yours was my first impression too until I read the first few paragraphs.

Re:Look at the data

[Captain_Chaos]

Hmmm. The big bang posits a long period of time where everything is compressed, followed by an explosion which flares stuff out in all directions.

Actually, the big bang theory doesn't say anything about what happened "before" the big bang, and there's no reason to assume that the universe already existed, only scrunched up into a little ball.

Also, the "flare" caused by the big bang probably isn't shaped like that of a trumpet. According to recent theory, there was a very short period of enormous expansion in the beginning, followed by a long period of much slower expansion. Not the kind of exponential expansion that you would associate with the shape of a trumpet.

So, I think it's unlikely that this new theory and the theory of the big bang have much to do with each other, at least not in the sense that the big bang would explain the shape of the universe in this other theory.

Re:

[farmy4700]

I have actually used the hum of the florecent lights to tune my banjo before.

Klein Bottle

[jmpoast]

Maybe the universe is shaped like a klein bottle? The curvature at the end would be similar to the 'horn' model and it would explain the 'turning around' that allegedly occurs at the edge of the horn. Just trying to imagine traveling in a klein bottle is making my head hurt though.

So much for the Big bang

[MouseR]

Must have been something more like a "Big Hoot".

In the begining...

[WoodenRobot]

In the model, technically called a Picard topology, the Universe curves in a strange way.

In the begining was the words, and they were "Make it so"...

A "Picard topology", eh?

[HorsePunchKid]

I've ranted here before about the shoddy reporting that the New Scientist does. It's very curious to me that the only matches on Google for "Picard topology" are from this article. Can anyone shed some light on this situation? Picard groups are certainly well-known enough. If nothing else, it's something to be skeptical about. Is this really so new that nobody has ever mentioned in on the web, or is it just poor terminology? (Note that one of the scientists is quoted as using that term, but it's phrased in a way that makes it sound like the reporter put words in his mouth.)

Re:A "Picard topology", eh?

[Anonymous Coward]

Here is the original paper.

Re:A "Picard topology", eh?

[Anonymous Coward]

Check out the actual article, the "Picard" topology is named after E. Picard who proposed it (presumably in 1884, ref 18).

http://arxiv.org/PS_cache/astro-ph/pdf/0403/0403 59 7.pdf

Re:

[Anonymous Coward]

Evenings kinda slow down on the farm eh?!

Re:Frist psot

[Lumpmoose]

When the universe reaches the standing wave frequency of the Great Superstring, it will all vibrate apart.

I personally hope it will reach that frequency before it reaches the "brown noise".

Re:

[WinDoze]

A banjo is better tuned with a hammer. (Sorry... my wife plays banjo)

Re:

[clarkcox3]

Then your banjo was out of tune. 60Hz is actually closer to B-natural, the B-flat in that octave is actually 58.27 Hz (assuming a tempered A 440 tuning), while B-naturral is 61.74 Hz.

Picard

[tverbeek]

named after a Star Trek character.

This is just a hunch, but I bet "Picard topology" is named after Emile, not Jean Luc.

Re:Sounds

[SunPin]

No, those are the prophets of Mount Rushmore. The chip in your head is malfunctioning.

Ah the geeky irony.

[BobRooney]

If they are, then our Universe is curved like a Pringle, shaped like a horn, and named after a Star Trek character. You could not make it up.

For those who didn't RTFA, the name for the topological structure suggested is the "Picard Curve". Its no Dyson sphere, but it is the universe...

Brown Noise

[damiena]

Scientists believe it to be 92 cents below the lowest octave of E flat.

Temptation

[Alsier]

At an extreme enough point, you would be able to see the back of your own head.


In this situation, am I the only person that would be tempted to reach out and slap the back of my own head? "You idiot, look where you got us now."

Re:

[IsaacW]

actually, 60 Hz is closer to B-flat... 60 - 58.27 is 1.73, while 61.74 - 60 is 1.74.

of course, he never said that he tuned the B-flat on his banjo to exactly 60 Hz... he could have known about this discrepancy and tuned from the low end until the beat frequency produced by the combination of his B-flat and the 60 Hz was approximately 1.75 Hz.

A downward spiral

[tid242]

My universe is shaped like a downward spiral, i expect that given enough research, others will come to surmise that their universe is similarily shaped.

-tid242

Re:

[daeley]

A banjo is better tuned with a hammer.

Are you referring to a tuning hammer or to one you might find in, say, a hardware store? I guess it depends on how good a banjo player your wife is!

(Sorry... my wife plays banjo)

Ooooh, so much for that.

Explaination from an ast101 prof...

[prof_bart]

So here is the deal:

What do we mean by the topology of the Universe?

We sort of mean the 'shape'. It is easy to talk about 2 dimensional surfaces in a three dimensional universe - planes, spheres, funnels, etc. But the Universe has 3 (large) dimensions, not 2, so it is much harder. Normally, we think of the universe as a 3 dimensional equivalent to a plane - that is, in space, straight lines are straight, never curve back on themselves, and go on forever. Another common topologies which arise naturally from gravity theory are 'spherical' - where parallel lines eventually cross, and you can see the back of your head. The group in questions is proposing that the Universe is a 3d analog to the surface of a horn. Others have proposed 3d analogs to the surface of a doughnut....

How can one possibly determine what this shape is?

If the Universe is actually curved in some way, then light coming from distant objects will be bent on its way to us, distorting the images. For the global topology of the Universe, one wants to use the largest, most distant thing you can look at. The Universe is expanding and cooling. Light takes time to travel, so if you look far enought away, you can look far enough back in time to when the whole Universe was filled with a hot H-He plasma. This is called the Cosmic Microwave Background (CMB). Most recent topology studies have looked at the statistics of the fluctuations of this distant plasma for distortion in the image from what is predicted.

So, is this true?

Could be.... but the evidence is not compelling. The anomalies they are looking at are of rather low statistical significance, and the idea that the universe is just 'straight/flat' and boring still fits pretty well. And unfortunately, for the large scale stuff, the data isn't going to get any better. The problem is, we only have one Universe, and COBE and WMAP have measured the large scales as well as can be measured. The small scale distortions have more potential given upcoming experiments like Planck, and the WMAP year2 data.

Are we inside a black hole? I doubt it.

[Genady]

Remember though that the arrangement inside a blackhole is that of maximal entropy. No matter how you shake a blackhole it can't get any more disordered. Looking around the universe over time it's obvious that it is not in a state of maximal entropy, if it were time wouldn't appear to flow.

Now... our Universe could be just another 3brane in a larger multi-verse of multi-branes. There's nothing that says that a braneworld has to have a certain level of entropy, or that the levels of entropy can't change over time.

In other words...

[Ragnarok21]

...the universe is shaped like water in flushing toilet. Ok, that explains a lot of things.

Nemory

[Doc Ruby]

Of course, that's the threshold crossed by the "output" of a black hole, which appears in the next universe as a "deja vu". The black hole's input universe arrives in infinite subsequent universes, each separated by a single iota of information. That iota is recieved as the smallest, infinitesimal information change in the subsequent universe: in that universe's model of itself, in a mind, there is one extra metadatum flipped to "this exists".

Investigating this infospace led our schneidics lab to a vast, uncharted category of information science. We all know "memory": you know something that happened. And, unfortunately, "forgetting": you don't know something that happened. And "deja vu": you know something that *didn't* happen. We've planted the schneidics flag in "nemory": you *don't* remember something that *never* happened. We now believe that this "cold, dark information" composes the vast majority of information in the universe. We are currently investigating its application to the rest of the emerging field of schneidics. If you have experimental nemory data, please report it to our lab.

Re:Nemory

[Craig]

We've planted the schneidics flag in "nemory": you *don't* remember something that *never* happened. We now believe that this "cold, dark information" composes the vast majority of information in the universe. We are currently investigating its application to the rest of the emerging field of schneidics. If you have experimental nemory data, please report it to our lab.

Suggested sources:

• Federal Government's Press Release Archive.
• Lecture notes from any history course at Columbia.
• CBS Evening News.

... just for starters...

Here is original paper

[abomb77z]

Already posted by someone, but in an obscure place.

http://xxx.uni-augsburg.de/abs/astro-ph/0403597

Shows you that you really need to know what you are talking about if you want to make an intelligent comment about this paper.

Primal hum of the electrical grid

[Bikku]

Interesting side effect of the difference in AC power frequencies between US (60 Hz) and Europe (50 Hz). I recall reading about a study that asked groups of participants to mediate and then collectively hum a tone of "primal unity"

The USian group centred on a B-flat (multiple of 60 Hz), while the Europeans centred on an A-natural (multiple of 50 Hz).

Hardly qualifies as a controlled study. But still suggestive that the background EMF frequency and device hum has some unconcious influence on the psyche?

Laboratoire Emile Picard

[Ra5pu7in]

How very strange - my Google search came up with several references to the Picard Theorem's from Laboratoire Emile Picard. Of course, these were in French, so perhaps filtering is to blame.

Re:

[IsaacW]

actually, (61.74/60) is less than (60/58.27), not the other way round, but you are right to say that this makes 1.74 a smaller percentage of 60 than 1.73 is of 58.27.</nitpick>

frequency is a continuous property of a wave... whether you choose to select linearly or logaritmically spaced points is up to you. over large scales (i.e. multiple octaves or decades), it is generally more useful to choose logarithmically spaced points, because you want to treat low octaves with the same number of points as high octaves. over small ranges (here only 3.47 Hz or about 5.78% of the nominal 60 Hz), it makes sense to deal with linearly spaced points, because the imbalance between octaves cannot come into play. in this case, if you played the B-natural against 60 Hz and then played the B-flat against 60 Hz, the resulting beat frequency signals would sound essentially the same, as the difference between them would be only 0.01 Hz.

Re:That's ridiculous

[Jim Starx]

Your taking the map analogy a little too far. The point is some believe that the universe has a finite size but is without bounds. Like the surface of the earth is finite in size but without bounds. If you continue in a straight line starting at one point on the earth you'll eventually end up in the same spot. In the universe it's believed that if you keep going in a straight line in any direction you'll eventually end up where you started. Of course it's also been shown that if relativity holds true (meaning you can't travel faster then the speed of light) the amount of time it would take to do that would exceed the lifespan of the universe.

I've read one to many Hawking books.....

This explains the question.

[Zapdos]

Why are we always so horny?

Hasn't it always had that shape????

[spectecjr]

Take the big bang. Infinitesimal point.

Explode that shape over time.

Now look at it four dimensionally...

Surely you end up with an r^2 curve rotated through 3 dimensions, with r on the time axis... ... which looks exactly like a horn.

Greg Bear beat them to it

[ralphclark]

In "Eternity", the sequel to "Eon", Ser Olmy returns to 21st(?) century Earth having taken a *very* long round trip via the opposite end of the universe - which turns out incidentally to have been be horn shaped - in the traditional sense of a curved or rolled up tube with a wide bell-like flaring at one end.

So there.

Lost guide

[Tablizer]

At an extreme enough point, you would be able to see the back of your own head. It would be an interesting place to explore

"Hey you! I'm lost. Can you tell me where I am?....Why won't you face and answer me?....Face me like a man, you balding fat-ass bastard!....Hey! Isn't that my same jacket you have on? It looks a lot better on me, shy Dickhead. Maybe a little phaser blast will bring you out of your shell. *ZZzzaap!* Ow! Fuck! Where'd the hell that come from? Make them stop or you'll get another one..."

Paper Reference

[SiliconEntity]

The scientific paper is available from the physics e-Print archive. According to the abstract:

We analyse the anisotropy of the cosmic microwave background (CMB) in hyperbolic universes possessing a non-trivial topology with a fundamental cell having an infinitely long horn. The aim of this paper is twofold. On the one hand, we show that the horned topology does not lead to a flat spot in the CMB sky maps in the direction of the horn as stated in the literature. On the other hand, we demonstrate that a horned topology having a finite volume does explain the suppression of the lower multipoles in the CMB anisotropy as observed by COBE and WMAP.

And by the way, it's named after Emile Picard from 1884, not Jean-Luc from the 25th century.

But that means

[Golobarti]

That faster then light travel is possible. All you have to do to achieve it is jump from one loop of the horn to another outside of the universe. The tighter the loops the more shortcuts are possible. Problem solved. Now if I can only get this antigravity module to start working....

Imposssible

[jetsfandb]

All evidence clearly points to Homer Simpson's doughnut shaped universe theory!

geometry versus "dark energy"

[peter303]

Some physcists such as Alan Lasserby suggest mysterious forces can be explained by slight pertubations of Euclidean geometry on a universe-size scale. This could explain the anti-gravity force called "dark energy". Its thought to compromise 70% the "stuff" in the universe, but obliviated by a geometric explanation.

Gabriel's Horn

[Zen Programmer]

The Picard topology sounds like what was referred to in my math class as Gabriel's Horn.

An apparent paradox concerning this shape's infinite interior surface area and finite volume is that one could never paint the entire surface area, but could simply fill it paint, thus painting it. However, the resolution to this paradox is that since the horn's diameter eventually becomes smaller than that of a paint molecule, that part of horn could never be painted.

Curved isn't necessarily finite

[billstewart]

There have been lots of discussions since General Relativity came out about what shape the Universe has. Many of the models have a curvature parameter that's more than, equal to, or less than the value for a flat universe.

• Some of the models are closed curves that are finite in size - the typical analogy is a 4-space hypersphere with a 3-d surface that the Universe maps onto, similar to the way the 2-d surface of the Earth is wrapped around a 3-d sphere and doesn't have edges. But that's not the only model. (The string-theory and membrane-theory folks add another half dozen dimensions to the mix, but the big dimensions can still mostly follow that model.)
• Some of the models say "no, it's not curved, it's flat, maybe a bit bumpy but it's really infinite".
• Some of the models say it's the opposite of a closed curve - these typically look saddle-shaped or horn-shaped, because instead of the curvature in the x direction and the curvature in the y direction both going the same way, they're going the opposite way.

A lot of this stuff tends to be related to models about how much matter and energy the Universe has - is there enough mass to make it close in on itself or not, and do we need to postulate lots of as-yet-undiscovered "dark matter" to make it heavier, or enough even-less-defined "dark energy" to blow it apart?

Universes Behaving Badly

[billstewart]

Sure, science cares about observing how things behave, but it does that in the context of making hypotheses about what's really going on, which go way beyond what we expect to actually be able to observe.

Sometimes the universe just misbehaves and fails to cooperate with your theories, which is when science gets to be fun - either your theories are thoroughly bogus, or they're slightly incorrect approximations, and this influences whether your previous models are or are not useful.