- #1
Hexorg
- 3
- 0
Hello, everyone.
This is my first post in this forums. I wanted to discuss a few concepts after reading Stephen Hawkin's "The Grand Design" book, and a search engine suggested your forums :)
Particularly, I want to talk about the fact that all the galaxies drift "apart" from each other. I understand how blue-shift and red-shift techniques work, but wouldn't you need to know some other factor as a reference point? In other words, when we observe the star's light, giving of a wavelength, say 580nm (I know starts emit all kinds of wavelength, but just use one for simplicity), how do we know that it's supposed to be smaller then 580nm (blue-shifted) or bigger then 580nm (red-shifted)? We'd have to know the compound of the galaxy to tell the actual spectrum that we'd see from it, wouldn't we?
But setting that aside, and working from the point that universe is expanding. Let's say that space-time = tXYZ (time, and 3 major dimensions). As lim(t) \rightarrow \infty, lim(tXYZ) \rightarrow \infty too, so wouldn't space-time expand just because the time is "running" forward?
This is my first post in this forums. I wanted to discuss a few concepts after reading Stephen Hawkin's "The Grand Design" book, and a search engine suggested your forums :)
Particularly, I want to talk about the fact that all the galaxies drift "apart" from each other. I understand how blue-shift and red-shift techniques work, but wouldn't you need to know some other factor as a reference point? In other words, when we observe the star's light, giving of a wavelength, say 580nm (I know starts emit all kinds of wavelength, but just use one for simplicity), how do we know that it's supposed to be smaller then 580nm (blue-shifted) or bigger then 580nm (red-shifted)? We'd have to know the compound of the galaxy to tell the actual spectrum that we'd see from it, wouldn't we?
But setting that aside, and working from the point that universe is expanding. Let's say that space-time = tXYZ (time, and 3 major dimensions). As lim(t) \rightarrow \infty, lim(tXYZ) \rightarrow \infty too, so wouldn't space-time expand just because the time is "running" forward?
