Issues of light

The only assumption any scientifc model is based on is the assumption that natural phenomenon have natural explanations. To say that this has been largely bourn out is an understatement ot the extreme.

To be fair (but probably confusing) it should be said that a sphere has an edge only in the third dimension. Within two dimensions it's unbounded. Imagine if you were a paper man who couldn't see into the third dimension and you lived on a sphere. Better yet you lived IN the surface of the sphere, so that the light you saw had to travel within that surface, too. You'd never see an edge to your universe, yet you'd know that it was finite because you could travel in any direction and return to your starting position. Furthemore there would be no place you could consider a "center" because there'd be no way to determine your absolute position on the sphere. (On earth, we solve this problem by setting up an arbitrary system of latitude and longitude that we all agree to use.)By analogy, our universe could be a kind of fourth-dimensional hypersphere, with no boundaries that we are able to percieve. It would still be finite in volume, but you could never leave it by three-dimensional travel. There would be no center of the universe - or rather, such a center would not be within the universe we could travel to. Like the center of a sphere is not found on its center but within its volume, the center of the universe could only be found in its fourth-dimensional hypervolume.Something like that. It's pretty confusing to try to think about higher spacial dimensions. But that's the long and the short of it. The universe can be unbounded but finite to us if the edge is not located within three dimensions.

The thing is, as I understand the theory, that simple time dialation wouldn't advance radiometric and biomolecular "clocks" without doing the same thing to human perception.That is, even if a bazillion earth years are made to fly by in the space of six days (relative to god, or some other off-world observer), that still means that, on earth, any record of time - even perception - would still report bazillions of years, and the earth, relative to us who live on it, would still be 4 billion years old.I mean, if you're on the proverbial rocket ship, and somehow you're moving so fast as to alter your time, it's not like you observe clock hands spinning like table fans. Clocks still tick at the rate of once a second, by your perception. But if I look in the window of your ship right as it passes by, the clocks look different (slower? faster?) to me.Does that make sense? Relative time doesn't solve any problems for young earth creationists. No matter what kind of time dialation we're under, a million years still looks like a million years to us.

There's some thought that the universe hase no edge - is unbounded in three dimensions - so in that circumstance, "center" doesn't really have a meaning. Well, it would - but the center of the universe would not be found within its three-dimensional volume, just as the center of a sphere is not found on its surface. The reason, then, that distant galaxies recede faster is because the space between all galaxies is expanding. No matter where you view this phenomenon, in a relative universe you appear to be at the center of it because everything is moving away from you.Or that's how I understand it. If the universe does have a three-dimensional edge then it is receding somewhere around the speed of light. What mechanism would ensure that the clock keeps pace with the edge? That seems to me to be the only situation where the clock would time-dialate. Nothing about the edge would "drag" the clock along with it, would it?

I'm, er, pleased that you think so - I don't have any kind of formal training in cosmology or physics, just a good copy of "A Brief History of Time." (The illustrated version.) Well, what if (to cite a common example) god simply made the universe and everything in it one second ago, complete with yours and my brain filled with a lifetime of fraudulent memories? Once we assume a god who can make things older than they are we have to wonder if a god of truth would mislead us so. When I believed in god, I rejected such a hypothesis. Now that I don't believe, it doesn't matter. Why? Because of some quasi-metaphysical speculations about light? I don't even understand what light has to do with radioactive decay. I'm not saying it doesn't, just that no one's ever elucidated such a connection to me.Suppose there is a connection. Light behaves in ways that are weird under certain circumstances - against common sense to most people. The thing is, light behaves exactly as our theories say it should, no matter how weird. When Maxwell first determined the field equations for light, they stipulated phenomena that people wouldn't accept until Einstein.Light doesn't always make "sense", in the sense of acting like common experience suggests it could (how could the speed of anything, much less light, be the same to all observers regardless of their vector?), but it always acts in ways predicted by theory.Since light always behaves as it should, why shouldn't radiometric dating? I don't see any reason to throw it out. No one has claimed that radiometric dating can't give bad dates in certain circumstances; however those circumstances generally leave evidence that we can use to correct the dates. I don't see any reason to discard those dating methods as yet.

It just sounds like you're asking "can we know light in it's true light-ness?" Which begs the question if it is even possible to truly know the essence of something in it's self-ness. I doubt it is so I don't find your questions very fruitful.I can come up with models to explain the data from my senses but I can't ever experience reality devoid of the filter of perception. So why bother referring to the basic self-ness of anything? Doubtless there's better philosophy to explain what I'm talking about, but maybe I'm coming through with this anyway.

Light travels at the same speed to all observers, as John said. therefore an expanding universe wouldn't change the time inbetween the signals. It would red-shift, but that's about it... John said all this but you apparently missed it.[This message has been edited by crashfrog, 06-04-2003]

I don't think that's right. Firstly, with no inertial frame of reference, an expanding universe is no different than observers travelling away from each other.I find it hard to break this down, mentally - maybe you can help me out. Let's pretend we're on trains, heading away from each other at some significant speed. You send me pulses from your light clock, one a second. We're accellerating away from each other (to mimic the effects of an expanding universe.)In that situation, do I observe the pulses slowing down, falling behind my own timer? It's too complicated for me to puzzle out on my own. I'm hoping you can help me with this.