Can astro' doppler shift techniques point to the Big Bang origin of the universe (from greatest recession)?

Question

Presumably, observations made in the direction of the origin -- and beyong the origin -- should yield the greatest relative speeds (since directions are opposite), indicating the direction of the origin?
Conversely, observations made in the opposite direction -- away from the origin -- should yield the lowest speeds since the directions are the same.

Answer 1

In a word, no.
When you look that far away, you are looking back into time to the beginning of the universe.
But if the universe did originate from the big bang, i.e, a point source singularity, then all of the observable universe that far away was one point (or relatively close to it)! So what would it really mean for the big bang to have come from a certain direction? It came from all directions!
Observations made that far away are made in the infra-red and microwave also. It forms the 2.7°K background radiation. This background radiation is not uniform, but it is also not as polarized as you may think. It does form the dipole anisotropy, but is not in general due to the big bang.
See:
http://map.gsfc.nasa.gov/m_uni/uni_101Flucts.html

Answer 2

This is a clever suggestion but one which would not work on at least two counts - practicality and theory.

Firstly practicality. No current telescope is powerful enough to be able to catch the light from anything more than a fraction of the objects in the Universe, and many that you could in principle see are hidden behind dust clouds. It would thus not be possible to gather data from enough objects to make the assessment feasible. You would only know about the relative speeds of nearby objects, not all of them, and so could not derive an overall result. This situation is unlikely to change because even if sensitivities increase you will eventually get to the point where the speed of recesssion is close to that of light and so, by definition, you will not be able to see any further.

More seriously though, there are several theoretical reasons why it would not work. Firstly, in the instant after the Big Bang the Universe was simply a "ball of energy" (in rather loose terminology!). Cosmologists believe that this "ball" then underwent a tremendous expansion very quickly - the inflationary phase. One effect of this inflation was to erase all memory of previous states i.e. by examining the situation afterwards you could not deduce what happened before. There were no particles as such and certainly no atoms: the ball simply radiated light, which is now what we see (incredibly red-shifted) as the 2.7K black-body background radiation mentioned by another answerer. After inflation the Universe slowly cooled, allowing first elementary particles and then atoms to form. However, this allowed electromagnetic fields to exist which strongly influenced the direction that things travelled in - electrons go in spirals or curves, for example. Then when structures began to form gravity again affected directions.

The upshot of all the above is that although we can say that each part of the Universe is expanding from each other part (and at an increasing rate, it seems) it is neither sensible nor possible to "track that expansion backwards" to find the place at which the original singularity existed. As an analogy, imagine you are short-sighted and are in the centre of an enormous field together with several thousand other people. On a first command, everyone starts running in a random direction for a short time ("inflation"). On a second command they stop and walk towards what they see as the edge of the field, some directly and some in a curve, only changing direction if they bump into someone. After a while, what can you see? The answer is just those people quite near to you (as you are short-sighted), who will be diverging from you but whose path now doesn't give you much clue as to where they originally started from.

As a slight aside, I think that cosmologists are quite happy with the idea that there was indeed just one point of singularity, contrary to another answer. I don't think it has ever been suggested that the Big Bang happened "everywhere at once". This would probably be ruled out by quantum theory anyway as the fluctuation in the quantum vacuum that gave rise to the Big Bang was statistically very unlikely in the first place so to have it going on in multiple locations is not really possible.

Answer 3

No - because the expansion is in multi dimensional space so tracking them back would work not because the centre doesn't exist in 4-D space.