The Edge of the Universe - Page 2

"Think about it this way. Empty space infinite. Clusters of clusters of galaxies slowly apear over infinite time and space only to grow hot and then expand and become cold and sterile. It happens every where infinitely. The only thing to determine any relativety and seperation in the events and in the singularity of this existence is a consciousness within the existence.

Such is the universe. And such is us."


I think this is the most logical idea. If there is no space outside the universe (the stars and planets), then what does matter expand into?

2 scenarios, the universe has an edge or the universe is like pacman, you go out the right side and come in the left end.

or like going beyond the earth's atmosphere, you must obtain a maxium velocity [e=mc2] at which point you form a curved path around it?

i like the pacman idea lol, wouldnt that be fun.

Or what about it keeps going and going like the energizer bunny, no edge and no.... pacman

Empty space seems like it would be infinite. Matter (stars, planets, comets, dust) seems to be expanding in the empty space. The only edge of the universe would be the furthest matter that is expanding into the empty abyss.

It seems to make sense that if conditions are right, the matter could start evolving....I think of earth as a piece of bread sitting out on the counter....pretend the counter is just empty space. Eventually mold will develop onto the bread. In a sense, we're like smart mold!

You're all considering the universe as matter expanding within infinite void. That's not correct.
The universe is space expanding within nothingness. Nothingness is not the same thing as void; "void" needs a space to be empty, while there's simply no space outside the universe.
If there are other universes, there must be nothingness between them; if it doesn't, it's still one universe.
You don't need to continuously give energy to the expansion. It's still powered by the night infinite energy of the big bang. Remember, if you move something and there's no opposite force to stop it, it will keep going forever. Without friction in a void space, you could kick a tin can from orbit to another galaxy. It would just take a little time (if the galaxy isn't expanding in another direction more quickly than the can, in that case it will never reach it).
Expansion could stop only if the gravitational total force of all the matter in all the universe is enough to counter it, leading to a big crunch.
Apparently, there's not enough gravity according to the latest experiments, but it's still under some debate.
Space expands faster than light, by the way. Things can't move in space faster than light, but space isn't expanding "in space". Not making this up, read Scientific American.
So the question is, what do you see if you fly to the edge of the univese ? If spacetime is curved enough, you'll never see it as in a pac-man game; you could keep walking forever on Earth, for an infinite time, but you'll never find an "edge" because you're walking on a curved space.
If it isn't curved enough, you'll see simply nothing. Space expands far faster than matter or energy. At a point, you'll be the moving edge of the universe, I guess.

I've always believed that infinity was a psychological symptom of our inability to contain the world in our extremely limited perception of three-dimensional space which, as Kant asserted, is merely a category of thought and perception and not a physical property of the external world. When we realize that there are two spacial infinities (the infinitely large in a macrocosmic sense and the infinitely small in a microcosmic sense) we discover that we are trapped between these two infinities in the physical material plane of three-dimensional space, which may be thought of as a psychological construction and not an actual objective reality. When we try to contain the external world in both a macrocosmic and microcosmic sense our comprehension of the external world seems to thin out in "curves of thought" marked by infinity in these two directions. Try to imagine space represented by a vertical line curved as if on a sphere. As we "look up" we lose grasp of the external world of the infinitely large as it curves to dissolution we recognize as infinity. As we "look down" towards the world of the infinitely small our comprehension of the external once again curves to dissolution in that direction as well. Between these two infinities only does three-dimensional space work because it is a tool of the mind and not an actual physical property of the external world. We could do the same for time (which may also be a category of thought and perception) by representing it with a curved horizontal line marked at both ends by the infinite past (to the left) and the infinite future (to the right). Where the vertical line of space and the horizontal line of time cross is the vertex, a point representing our consciousness. The hypothetical centerpoint of the universe, then, exists within our own minds from which the three perpendicular lines of three-dimensional space exend outwards. It is our consciousness that divides time into past and future, and the present really constitutes only a miniscule point along this hypothetetical line of time. Wouldn't we be suprised to discover that the line of space and the line of time actually meet on the other side of the hypothetical surface of the sphere on which they lay to form two circles--the circle of space and the circle of time--representing the ancient mystical concept of "As above, so below" and the Orboros, the snake biting its own tail to form and endless circle of time we call eternity? Moreover, it is believed quite possible to expand the point of consciouness, the vertex, to includie more elements of past and future in our experience of time to also expand our perception of space, to percieve a higher perception of space which would make the question as to whether the universe is finite or infinite rather unimportant, don't you think?

To extend the pacman notion. In general relativity we deal in manifolds. A manifold is a generalisation of a surface. Where as a surface may be thought of as 2 parametric dimensions embedded in 3 dimensional space a manifold may be thought of as m parametric dimensions embedded in n dimensions. So the world of pacman is analogous to a donut. Imagine stretching the screen round so it forms a cylinder and then bending the cylinder to join the ends and you'll see what I mean. Now in big bang theory, particular that school of thought that likes to talk of a big crunch, the universe is said to be analogous to a closed shame link a sphere or donut growing from a point and shrinking back down to one. So galaxies can be thought of as siting across this surface and expanding along with the shape. Of course there are other manifolds that are open (geometrically as shapes) such as an infinite plain yet I'm not certain if Einstein's equation would permit a matter rich universe to have such a topology. Of course not every one is satisfied with Einstein's equations and so there are other equally possible theories accounting for expansion and the beginning of the universe.

I've always found the many theoretical "shapes" of the universe, from euclidean, to spherical, to hyperbolic, quite interesting. But, for me, the strangest of shapes always struck of the imagination to me, like an artist who necessarily shapes his clay to conform to his mathematical vision of what the clay should be. Unfortunately, I feel that way about all of modern science: very useful in a practical sense, but never approaching answers to the most difficult questions.

It's one of the fundamental limits of science. It can only really help us discover truth with in certain limits. Once we move beyond the limits of what we've previously been able to observe we discover new scientific laws. Since we can imagine a good deal more than we can observe we are left with more speculation than fact when we try to use science to answer such questions as the origins of the universe or even the species.

Look around you, the space between you and the computer, between you and the ceiling, space does not 'expand', it is already there.

Infinity and finiteness are the same, mere concepts in the mind of man.

though we appear to be getting back to the usual philosophy discussions that occur in more or less every thread on this forum, i would agree with code warrior, science allows us to define what we observe, but that is its limit. it cannot tell us what we dont already know, it just tells us the how.

I love the way people talk about bent space or the curvature of the universe. If the universe was infinite, its curvature could not be defined. Bent space is an experimental expression that is so abstract that it has no meaning and doesnt help us understand the nature of this universe. BS, if you ask me.
I also find the concept of a nothingness impossible. If there was nothingness around our space, its vacuum would be infinite. We couldnt exist inside nothingness.