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Vern,It gets dark at night.That may not seem a very important observation but it proves that the universe is in some way finite.If it were not then, along any given line that you might look along at night, there would be a star. The ideea that the universe is always here and always has been can be ruled out every time the sun sets.
Olbers paradox requiring the universe to be in some way limited in space or time only applies to our observable universe. there is absolutely no reason why that represents the entire universe.
It gets dark at night.That may not seem a very important observation but it proves that the universe is in some way finite.If it were not then, along any given line that you might look along at night, there would be a star.
You had me thinking there....but this is not necessarily true. Light gets bent, light gets blocked out, our own atmosphere filters out great swathes of starlight. Not to mention that if mere streetlighting can so adversely affect the amount of light we perceive from beyond their range, that closer stars and galaxies might equally be seen to do likewise.
This is actually a red herring because if the energy didn't reach us it would be heating up the dust etc. in between until it was white hot and we'd still end up with an infinitely bright sky if that were all there is to it.
Why is there a universe?
If there was a big bang, what came before it, and before that, and so on?
Surly nothing should be, but it is, why?
Quote from: Bored chemist on 24/01/2009 19:41:14Vern,It gets dark at night.That may not seem a very important observation but it proves that the universe is in some way finite.If it were not then, along any given line that you might look along at night, there would be a star. The ideea that the universe is always here and always has been can be ruled out every time the sun sets.That is true only if you consider light to be ageless. The tired light scheme has light continuously converting to mass. When starlight contributes to the temperature of space debris it becomes less energetic eventually being completely consumed.
Quote from: Bored chemist on 24/01/2009 19:41:14Vern,It gets dark at night.That may not seem a very important observation but it proves that the universe is in some way finite.If it were not then, along any given line that you might look along at night, there would be a star. The ideea that the universe is always here and always has been can be ruled out every time the sun sets.You had me thinking there....but this is not necessarily true. Light gets bent, light gets blocked out, our own atmosphere filters out great swathes of starlight. Not to mention that if mere streetlighting can so adversely affect the amount of light we perceive from beyond their range, that closer stars and galaxies might equally be seen to do likewise.(this isn't an argument that the universe is infinite because of that, merely that the point - though initially compelling - doesn't necessarily stand up to scrutiny. [])
Space is not empty. Light will collide with particles smaller than atoms and as big as planets and become spent as it travels long distances, lending people to believe the universe is finite.
Quote from: andy054 on 24/01/2009 18:15:26Why is there a universe?Because somewhere was needed in which to put everything.
Quote from: Andrew K FletcherSpace is not empty. Light will collide with particles smaller than atoms and as big as planets and become spent as it travels long distances, lending people to believe the universe is finite.Surely, it collides with particles that make up the planet, not the planet itself.
I think that if light loses energy to mass as it ages the paradox will also go away. Maybe someone has detailed the math to show the paradox; I have never seen the math to see what their given values are. We might find a problem with the given values.