Quote:
Originally Posted by Clegrand
One thing that has always eluded my understanding is that isn't the universe an ever expanding sphere with us constantly moving within it. So wouldn't we see different lines of sight from our relative position each time we make an observation or take a distance measurement. What formulas have been constructed for this?
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Hi Clegrand
Google 'Hubbles Law' and 'redshift'. There is a ton of good stuff about this. It was just the kind of observation you're talking about that led to the discovery of the expanding universe. Hubble observed in 1929 that distant galaxies in all directions were accelerating away from the Milky Way, showing that contrary to what scientists believed, the universe was expanding. Einstein's own calculations had shown him the universe must expand or contract, but he didn't trust them - until Hubble's observations. So your intuition is bang on!
Our 'observable' universe is spherical, but this is simply a function of time and the finite speed of light - we can only see as far as light has been able to travel in all directions over the age of the universe. The actual 'shape' of space is not thought to be spherical, but rather is flat with a margin of error of about 2% I think, over the entire universe that we can see. Space can take the shape of a cube or donut or soccer ball for example, while remaining 'flat' (or Euclidean), finite, and unbounded.
It still
could be a sphere as I understand it - just a bloody big one, so big it
appears flat on the scale of the observable universe!
Weird huh?
Pamela and Fraser, in the latest podcast talk about how the shape of space exists in multiple dimensions that are impossible for our three dimensional brains to visualise - other than to compare them to familiar three dimensional shapes like spheres and donuts and soccer balls. You have to consider just the 'surface' of the shape, which is two dimensional in our three dimensional space, then extrapolate it to higher dimensions. Then your brain melts.
