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Author Topic: How do we see light from the distant past?  (Read 8573 times)

Offline Mr. Data

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How do we see light from the distant past?
« Reply #25 on: 02/07/2011 15:27:33 »
Expansion of local space in present time is very slow. Very slow next to the speed of light. Inflation played the largest part in the phenomenon the OP speaks of.
The expansion of local space is, and always is, zero. Local space is euclidean. If we speak about small regions, then it depends how big a region we are talking about. On large scales, the expansion of the universe in the current era is definitely superluminal.

When I said local space, I did not mean it in the ''mathematical context'' you have taken it for. I mean it for a general case where we measure the speed in which our own star system is travelling through space. All star systems, and even larger scale structures (in their own local sense) are all travelling through space at different speeds: And as Prof. Hawking assures us in his book ''A brief History of Time'', some of the galaxies are even moving near at the speed of light. This is because of an inhomogeneous spacetime expansion rate which was left in this state from inflation.

You are also wrong in stating that ''On large scales, the expansion of the universe in the current era is definitely superluminal.''

As far as I am aware from the data, only the most distant galaxies are now receeding at a superluminal speed. I don't see any data suggesting that the speed we are moving at measures the same.
 

Offline yor_on

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How do we see light from the distant past?
« Reply #26 on: 15/07/2011 02:31:24 »
Mr Data, the expansion is what does it, there are no objects in space going FTL. But with an expansion acting on space all distances grow, and the further away the faster they will seem to move. It's a very weird way of FTL but, just as PhysBang points out, it will pass FTL for us looking, and those looking back will find us doing the FTL.
 

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How do we see light from the distant past?
« Reply #26 on: 15/07/2011 02:31:24 »

 

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