20 May 13
Originally posted by KeplerYou apparently did not look at the video. Therefore, you get an F grade on that one.
They aren't assuming long periods of time, they are using the data available. If that is assuming then so are you when you assume that there must be a creator god. You should not be assuming at all.
The Instructor
01 Jun 13
Originally posted by twhiteheadUnless the universe is infinite, it would have a border even if it's not a well defined border. So are you saying the universe has no border, but continues on into infinity? If you're talking about a universe that folds back onto itself, that just proves the universe is finite... it folds back onto itself because there is literally no where else to go.
The universe does not have a center. It cannot have a center because it doesn't have edges.
By the way, here's another riddle... if a beam of light reaches the border of the universe, where does it go from there? Can a beam of light reach the border and continue out into nothingness? Or is light confined to only travel within the borders of a finite universe?
01 Jun 13
Originally posted by lemon limeThe surface of the earth is finite, but has no border. You can travel West forever.
Unless the universe is infinite, it would have a border even if it's not a well defined border.
So are you saying the universe has no border, but continues on into infinity? If you're talking about a universe that folds back onto itself, that just proves the universe is finite... it folds back onto itself because there is literally no where else to go.
I do not know whether it is finite and 'folds back on itself' or whether it is infinite. What I am fairly sure about however is that it does not have edges and thus has no centre.
By the way, here's another riddle... if a beam of light reaches the border of the universe, where does it go from there? Can a beam of light reach the border and continue out into nothingness? Or is light confined to only travel within the borders of a finite universe?
Hence my claim that no such borders exist.
01 Jun 13
Originally posted by twhiteheadI agree that the universe is something like the earth, only larger. However, to determine if it has a border, it would be good to define what we mean by border. The Merriam-Webster On-line Dictionary has this as its number 1 definition for border:
The surface of the earth is finite, but has no border. You can travel West forever.
[b]So are you saying the universe has no border, but continues on into infinity? If you're talking about a universe that folds back onto itself, that just proves the universe is finite... it folds back onto itself because there is literally no where else to go.
I d ...[text shortened]... vel within the borders of a finite universe?[/b]
Hence my claim that no such borders exist.[/b]
1. an outer part or edge
So does the earth have an outer part or edge? I think we can say yes. Now if the universe is like the earth, it will most likely have an outer part or edge too. Am I right?
The Instructor
01 Jun 13
Originally posted by RJHindsIt is not like Earth. We are inside a kind of multidimensional bubble where space has a curve to it but in all three dimensions. The gist of that is, if you had a spaceship that could go the speed of light or close, you go in a straight line, what LOOKS like a straight line, eventually you come back to the same place you left and it does not matter what direction you originally start out in, all directions lead back to home. In order to see an edge you would have to travel in a higher dimension than our big 4.
I agree that the universe is something like the earth, only larger. However, to determine if it has a border, it would be good to define what we mean by border. The Merriam-Webster On-line Dictionary has this as its number 1 definition for border:
1. an outer part or edge
So does the earth have an outer part or edge? I think we can say yes. Now ...[text shortened]... ke the earth, it will most likely have an outer part or edge too. Am I right?
The Instructor
01 Jun 13
Originally posted by sonhouseThe difference is that we live on the outer part or edge of the earth rather than inside it like with the universe. So if we were able to go out to the outer part or edge of the universe, we would be traveling around the outer edge just like we do on the earth.
It is not like Earth. We are inside a kind of multidimensional bubble where space has a curve to it but in all three dimensions. The gist of that is, if you had a spaceship that could go the speed of light or close, you go in a straight line, what LOOKS like a straight line, eventually you come back to the same place you left and it does not matter what dir ...[text shortened]... to home. In order to see an edge you would have to travel in a higher dimension than our big 4.
The Instructor
02 Jun 13
Originally posted by twhiteheadI still don't know what you mean by "edges". When I said "border" I was talking about the outermost parts of the universe. It doesn't matter if the universe rests on the skin of a hollow sphere or what its shape is, if we are talking about a finite universe then there is a limit to its size. And where ever that size ends and nothingness begins is the border.
The surface of the earth is finite, but has no border. You can travel West forever.
[b]So are you saying the universe has no border, but continues on into infinity? If you're talking about a universe that folds back onto itself, that just proves the universe is finite... it folds back onto itself because there is literally no where else to go.
I d ...[text shortened]... vel within the borders of a finite universe?[/b]
Hence my claim that no such borders exist.[/b]
Moving forever west along the suface of the earth doesn't prove there is no border between where the earth ends and space begins. And how does a question about light prove the universe has no edges? A cube has edges and a sphere has no edges, but both have a border... the surface of both are the borders. And they both have centers.
This conversation is doomed to go nowhere if we can't agree on definition of terms.
02 Jun 13
I mentioned one theory that says the universe folds back onto itself. That's actually a very poor description of what the theory says, but there is no way to accurately describe what a universe like this would look like. It takes into account the bazarre nature of nothingness and the impossibility of trying to travel somewhere when there is nowhere to go. According to this theory if you try leaving the universe you will find yourself entering it from the opposite side.
I don't have a problem believing that "the nothingness" won't allow you to leave. But if leaving means entering from the opposite side of the universe, that is something I have trouble wrapping my head around. According to this theory, if you were able to look in a straight line with no limitation as to how far you could see, the universe would appear to extend into infinity. It would also mean you could see the back of your own head.
02 Jun 13
Originally posted by lemon limeIf the universe is curved in higher dimensions then it may be finite and yet have no edges, just like the surface of the earth has no edges in two dimensions.
I still don't know what you mean by "edges". When I said "border" I was talking about the outermost parts of the universe. It doesn't matter if the universe rests on the skin of a hollow sphere or what its shape is, if we are talking about a finite universe then there is a limit to its size. And where ever that size ends and nothingness begins is the border.
If the universe fits your description and there exists 'nothingness' beyond a certain point, then I would include that nothingness in the universe and it would presumably be infinite.
02 Jun 13
Originally posted by lemon limeYet you have no problem with the knowledge that if you travel West, you will get back to where you started?
I have trouble wrapping my head around.
That space time is not flat is a consequence of Einsteins general relativity. Light travels in a straight line, yet we still get gravitational lensing. Hence one can get parallel lines meeting, and triangles with angles not adding up to 180 degrees.
02 Jun 13
Originally posted by twhiteheadInfinite nothingness? Are you aware of what nothingness is? There is nothing in nonthingness that can be called finite or infinite. No mass, no space, no distance, no time... there is literally nothing to be found in nothingness.
If the universe is curved in higher dimensions then it may be finite and yet have no edges, just like the surface of the earth has no edges in two dimensions.
If the universe fits your description and there exists 'nothingness' beyond a certain point, then I would include that nothingness in the universe and it would presumably be infinite.
02 Jun 13
Originally posted by twhiteheadSo how would you explain how leaving the universe at one end means entering the universe from the opposite side? I wasn't telling you what you believe about the universe, I was telling you about someone elses theory. I don't necessarily agree with that theory, or yours either for that matter. You have to remember these are just theories, and not established facts.
Yet you have no problem with the knowledge that if you travel West, you will get back to where you started?
That space time is not flat is a consequence of Einsteins general relativity. Light travels in a straight line, yet we still get gravitational lensing. Hence one can get parallel lines meeting, and triangles with angles not adding up to 180 degrees.