If Space Wasnt Infinite

Yeah, yeah I have this great book called the Fabric of the Cosmos by Brian Greene and he was comparing the universe as a Balloon, and the galaxies as dimes placed on the balloon. As the balloon expands the dimes expand with the balloon but dont actually move away from each other. So basically our galaxy sits on top of the expanding universe (balloon) we're just along for the ride.

 

The shape of the universe - according to the most recent experiments - is flat. There's an outside possibility that it could be spherical or saddle-shaped, but a flat universe appears to be the most likely.

I think the doughnut-shaped universe has been out of fashion for a while now, but can't be completely ruled out yet. Kudos for knowing that Pacman's universe is doughnut-shaped by the way.

 

Arent those the 3 shapes that represent the 3 types of topological surface in a 3D space as opposed to the shapes of the universe. The universe being one of those 3 covers every possible 3D shape I believe.

 

so Kandahar, in the beginning, there was a single pint, and that was it? and out of that point came space as well as matter? where do scientists believe the point was before all of this happend?

 

That point began as a theoretical point- not height, no length, no width. A virtual point, if you will.

That point still exist. It's the universe itself. The apperent "difference in size" is more accurately a "distance in time". Hence, to say we are 15 billion years in time away from the big bang is much more accurate than to say we are 15 billion light years distance away.

 

It wasn't anywhere specifically. Asking "where" implies that space existed outside of that point, which it did not.

I think you're visualizing the Big Bang as a little dot of light, and you're "looking at it" from some other spot in the void. There were no places outside of that point where it could have possibly existed. It's like asking where our present-day universe is located.

 

so, where was all of this energy stored if it wasnt an actual point?

 

yeah, its kind of hard to not look at like that. its hard to imagine everything starting at just one point.

 

You are correct, my mistake.

I don't think there's really any 3D shape that can accurately describe the shape of the universe. Since it is boundless (but not infinite), in all three-dimensional directions, you can call it any shape you like.

 

At the moment of the big bang the universe was a singulairty. This is a theoretical entity to describe something of negligabe dimensions, in reality it would have dimensions of less than the planck length (1x10^-35m). Traditionally it made no sense to talk about before the big bang however higher dimensional theories can describe the big bang as an event within a higher space. However no theory can describe the conditions in our universe before 10^-43 seconds before the big bang as no theory exists to describe the interactions of forces at this time, the theory of quantum gravity is still at an early stage.
At 10^-43 seconds (the plank time) the universe had a temperature of around 10^32K. After this time gravity separated form the other forces and modern theories can begin to make realistic predictions as to what happened. The general trend is that it got bigger, colder and the forces separated. Now we have 5 forces gravity, electric, magnetic, strong and weak. Theoretically we are trying to work backwards and unite them all again. Electricity and magnetism were united back in the 19th century. The weak force has now been more or less united with electromagnetism and the strong force is making progress. All of these are explained by quantum theory however gravity is explained by general relativity. So far general relativity and quantum mechanics will not unite until this or something equal to it can be achieved then the very first stage of the big bang will remain a mystery.

 

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I was talking mathematically. I think its classifying by the divergance of the surface. Taking any function describing a surface taking div(func) if div is 0 then you get a flat surface the the saddle and sphere are positive of negative I cant remember which. I could do div(sphere) but its half 11.

 

what does it mean when people say "flat model of the universe"? is this flat as in just a black "sheet" that spreads in all directions forever?

 

http://map.gsfc.nasa.gov/m_uni/uni_101shape.html Try this website, its hard to explain divergence without maths. This website explains how it applies to the shape of the universe and the diagrams are very good as well. As well as the consequence of the different shapes.

 

Flat with ripples.

"Scientists found the universe is flat, with ripples that began as the tiniest variations in radiation left over from the Big Bang, which many cosmologists believe gave birth to the universe.
As it cooled after the giant explosion, the infant universe was actually making a sound and those waves produced the ripples.

The way galaxies are scattered across the sky now corresponds to the sound waves in the early times of the cosmos, researchers have found."

-http://www.theage.com.au/news/Science/Universe-is-flat-with-a-ripple/2005/01/12/1105423539638.html?oneclick=true

 

More or less, yes. Space can be considered a 3-dimensional black "sheet." A flat-shaped universe (as opposed to a spherical or saddle-shaped universe) will not curve into higher dimensions as you travel from Point A to Point B, unless there is a massive object like a star nearby.

In the spherical model of the universe, space naturally curves back in on itself even with no massive objects.

In the saddle model of the universe, space naturally curves away from itself even with no massive objects.

 

Just a note that there are many surfaces other than a plane that have 0 curvature. A cone and a cylinder are two examples. Your use of "flat" suggests that you are thinking of a plane.

 

Point taken. Though a cylinder cannot be described by a single continuous function, its surface is describe by 3 functions of which 2 have do curvature but 1 does. So I believe that for shpaes like that the situation becomes more complex. I think.

 

i just watched a dvd on black holes by Steven Hawking, and one guy kept talking about the possibility of entering another universe through a black hole. what makes scientists think that there are even other universes, let alone think it would be possible to enter them through black holes? or did they mean travel to other parts of our universe?