Bright Idea OTD
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RyanDev wrote:
Perhaps light disperses enough that at such distances we can no longer see it?
perhaps - but there is not evidence to suggest that individual photons 'diminish' over distance. Obviously teh light in general diminishes as it is spread out into an ever increasing sphere.
RyanDev wrote:
Space must go on forever, right?
Not 'must'. Intuitively that's how we think, but it's not necessarily the case. Much of the issue is in the terminology, really. Whether you subscribe to the big bang, or the god made everything theory, you tend to talk about 'before'. But if space-time was created at some point, then time was created, so there is no 'before' As for the wall, well, if the speed of light in a vacuum truly is an absolute and it is just not possible to exceed it, then from an individual's point of view the universe is finite with a radius equal to (C x age of the universe) because any information from father away than that is impossible to receive. As distant galaxies more away from us faster than C, the size of the observable universe is essentially finite - just because we can't possibly, ever, see beyond it. One could imaging being born an a planet right on the 'edge' of the observable universe, and could ask what you would see if you looked away from the origin of the big bang - but my understanding (which could be way off) is that there just isn't such an object. Wherever you are you will see everything expanding away from you - so nobody is sitting at the edge, looking at a big blank wall.
RyanDev wrote:
Fun to think about.
true Dat (as the kids say)
RyanDev wrote:
I'm going to go start counting the stars.
Good luck with that!
perhaps - but there is not evidence to suggest that individual photons 'diminish' over distance. Redshift? There is a velocity based interpretation of that but it could also be interpreted as photons losing energy over time, or a combination of the two. Perhaps they decay by splitting off a low energy photon and that's the microwave background. We wouldn't see anything in experimental situations because the effect, if it exists, is so small. There's no evidence for gravity waves either but that doesn't stop us spending billions on designing and building detectors designed to see them.
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Lol. Interesting to note that there's no joke icon on your message... :rolleyes:
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Quote:
I'm going to go start counting the stars.
Good luck with that :)
[Flags]
public enum Bool {
True, False, ForSure, Maybe, ProbablyNot, Depends, NotDecidedYet, Undefined
}private interface IShy { }
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575, 576, 577. Ah, please don't interrupt me. I'll have to start over. :sigh:
There are only 10 types of people in the world, those who understand binary and those who don't.
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Sorry, you were at 578. Didn't you miss a couple of them in Orion's Constellation? Ok, ok, I quit...
[Flags]
public enum Bool {
True, False, ForSure, Maybe, ProbablyNot, Depends, NotDecidedYet, Undefined
}private interface IShy { }
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Roger Wright wrote:
dark matter are drifting about
I've never seen Dark Matter drifting. ;)
That's because it's dark, and prefers to move about at night.
Will Rogers never met me.
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perhaps - but there is not evidence to suggest that individual photons 'diminish' over distance. Redshift? There is a velocity based interpretation of that but it could also be interpreted as photons losing energy over time, or a combination of the two. Perhaps they decay by splitting off a low energy photon and that's the microwave background. We wouldn't see anything in experimental situations because the effect, if it exists, is so small. There's no evidence for gravity waves either but that doesn't stop us spending billions on designing and building detectors designed to see them.
You're right, of course. The fact that we see red-shifted light with the shift proportional to the distance over very large distances ties in nicely with an expanding universe, but could be caused by tired photons, or something else entirely. As for gravity waves - didn't they find evidence recently?
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So, you may (or may not) know of Olber's Paradox - which essentially asks why the night sky isn't uniformly bright as, were it infinite, there would be nmo point in the sky with no star. I was reading about this and came across this prose:
Quote:
Were the succession of stars endless, then the background of the sky would present us an uniform luminosity, like that displayed by the Galaxy - since there could be absolutely no point, in all that background, at which would not exist a star. The only mode, therefore, in which, under such a state of affairs, we could comprehend the voids which our telescopes find in innumerable directions, would be by supposing the distance of the invisible background so immense that no ray from it has yet been able to reach us at all.
Bonus points to anyone who can guess who said it, without recourse to google searching the interwebs.
I think it was pretty well explained here: https://www.youtube.com/watch?v=gxJ4M7tyLRE&list=TLoPX9feW7CLMi6NoAa4eRV78j77s_09n9[^]
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You're right, of course. The fact that we see red-shifted light with the shift proportional to the distance over very large distances ties in nicely with an expanding universe, but could be caused by tired photons, or something else entirely. As for gravity waves - didn't they find evidence recently?
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So, you may (or may not) know of Olber's Paradox - which essentially asks why the night sky isn't uniformly bright as, were it infinite, there would be nmo point in the sky with no star. I was reading about this and came across this prose:
Quote:
Were the succession of stars endless, then the background of the sky would present us an uniform luminosity, like that displayed by the Galaxy - since there could be absolutely no point, in all that background, at which would not exist a star. The only mode, therefore, in which, under such a state of affairs, we could comprehend the voids which our telescopes find in innumerable directions, would be by supposing the distance of the invisible background so immense that no ray from it has yet been able to reach us at all.
Bonus points to anyone who can guess who said it, without recourse to google searching the interwebs.