Assuming the universe was created in a big bang, would it not manifest in the form of a sphere, rather than being flat or, as you suggested, hyperbolic? It seems that all matter would spread outward equally in every direction.

Assuming the universe was created in a big bang, would it not manifest in the form of a sphere, rather than being flat or, as you suggested, hyperbolic? It seems that all matter would spread outward equally in every direction.

It's talking about the geometry of it.

The universe is Euclidean meaning the lines won't intersect like you can see in the picture above the laser beams will just keep going.

"when we say the universe is flat it is not in the same sense that a piece of paper is flat, but rather means that the geometry of the universe is such that parallel lines will never cross, the angles in a triangle will always add up to 180 degress, and the corners of cubes will always make right angles. We call this kind of geometry (the kind you learned in school) Euclidean geometry.

It's easy to make examples in 2D space (ie. a flat piece of paper vs. a curved piece of paper, or the surface of a balloon). It's not so easy to illustrate flat 3D space - since we are 3D! So it's totally understandable that the concept is confusing" -source

More on Euclidean space.
http://en.wikipedia.org/wiki/Euclidean_space

Depending on how old the physics book you are reading is, i guess 10 to 15 billion years old.

Also several scientists argue that there are in fact a lot of alternative universes (~10^500) who could either be equally old or can be "seen" at different stages. Each of these "realities" have different amount of dark matter, so that just a part of them are like ours (mass, gravity, stars).

For geometry: The hypothesis of SuperStrings states that or basic three dimensional macrocosmos is expanded by 6 more dimensions in quantum mechanics. Those build up very complex orbitals (like those of an electron in an atom) that on theirselves build the enviroment to create the subatomic particles that forms mass and matter.

can be "seen" at different stages.

show me plz.

The universe is Euclidean meaning the lines won't intersect like you can see in the picture above the laser beams will just keep going.

same whit the open picture right?

the geometry of the universe is such that parallel lines will never cross

still going by the laser pictures. this is the case for all of them.

as for the last picture on page 15:
the view we have now is our sky (our point of view)
(it's looks kinda like a flat earth. but you gotta see it like a flat sky.)
you can see on the sides that there is beside the plane also a big "cloud" (they cut right through it)
if our point of view would be 90 degree to the left or right. then we would see a complete different picture. one where the "cloud" is in the middle. what would suggest a sphere shape universe.

(i still have no option to go search tho.)

still going by the laser pictures. this is the case for all of them.

In the open universe the two lines will curve away from each other, in this scenario a triangle wouldn't always add up to 180 degrees. The lines wouldn't remain parallel.

With the closed universe you can have parallel lines cross.

As seen here how parallel lines can cross on a sphere.
 

as for the last picture on page 15:
the view we have now is our sky (our point of view)
(it's looks kinda like a flat earth. but you gotta see it like a flat sky.)
you can see on the sides that there is beside the plane also a big "cloud" (they cut right through it)
if our point of view would be 90 degree to the left or right. then we would see a complete different picture. one where the "cloud" is in the middle. what would suggest a sphere shape universe.

The three dimension we move around in doesn't determine the geometry of the universe. Also there really isn't anything particular about our location in space. What we are looking at is going to be the same no matter where we are in the universe.

do we have the same definition for parallel?

the lines in that picture do not look parallel to me.

the lasers that the alien shot would not cross. =S

there really isn't anything particular about our location in space.

if the universe has a shape then there must be locations in this form.
like that star creating cloud, there must be something on the other side of that cloud that can see the cloud from a other perspective. maybe actually seeing the birth of stars in masses.

What we are looking at is going to be the same no matter where we are in the universe.

how can you be so sure that a other galaxy can't have a other perspective on the background radiation? their position in the universe is waaayyy off from ours.

Okay I think I woke myself up enough to try and answer.

the lines in that picture do not look parallel to me.

They are parallel when they are apart at the top right of the picture.

if the universe has a shape then there must be locations in this form.
like that star creating cloud, there must be something on the other side of that cloud that can see the cloud from a other perspective. maybe actually seeing the birth of stars in masses.

how can you be so sure that a other galaxy can't have a other perspective on the background radiation? their position in the universe is waaayyy off from ours.

What we are looking at is essentially the four walls in a room. We could use the room you're in. You as observer A at the computer and another person, observer B. They could be standing across the room. You both will have two separate perspectives of the room. You could see things in the room from different angles, but if you were both asked to create a geometric representation of that room, you would both end up with the same diagram. A room with the walls X far apart and Y high.

Another thing to note is our perspective in relationship to this permeating background radiation is changing. Not only are we moving around the sun the sun is in turn moving around the galactic center and the whole galaxy is also moving through space.

Some rough numbers the Earth spins about 1,00mph, which orbits the sun about 66,000mph which the sun orbits the galaxy at about 483,000mph and the galaxy is moving through space at about 1,300,000mph.

They are parallel when they are apart at the top right of the picture.

i think we have a other idea of parallel. i'm not seeing them in this picture.
except for the dot lines forming the open cube in the background.

you would both end up with the same diagram. A room with the walls X far apart and Y high.

i should learn more about the CMBR picture 1st.
sucks that my comp is gone atm.
is the red-ish  part of the picture part of the walls/universe? or only the blue-ish part.

the galaxy is moving through space at about 1,300,000mph.

maybe we get a other pics over 3 billion years or so. when we actually are in a other part of the universe. i dont think 1.3mill mph matters much in the universe.

i think we have a other idea of parallel. i'm not seeing them in this picture.
except for the dot lines forming the open cube in the background.

Would you say these two lines are parallel to each other?

is the red-ish  part of the picture part of the walls/universe? or only the blue-ish part.

The whole thing is, what we are looking at in that first picture is the heat from the microwave radiation. The density is what allows us to determine the shape of the universe.

maybe we get a other pics over 3 billion years or so.

That would be like you giving  different geometry of the room you're in than a person standing in the opposite corner. You're perspective of the "walls" from inside the room isn't going to change depending on where you stand in the room.

Look on some religious books and average all of the dates of how old the universe is is a good way to find out.