Single most important image

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DrRocket

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bearack

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Thanks for sharing. I've never seen that one before and again, makes things look so amazing!
 
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nova_explored

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SpeedFreek":3baoyml2 said:
I made a little video on this subject myself, a while back. I doubt it is quite as educational as the ones above!

Hubble: The Most Distant Galaxies
Hubble: The Most Distant Galaxies (widescreen)

Apart from the Hubble Ultra Deep Field itself, it features a 3D flythrough of the HUDF, a flythrough of the GOODS survey, a look at Abell 1689 which contains the most distant galaxy ever seen and a few other things!

Hey, nice video.

You know this makes me reminisce about my perception of expansion theory. And I always had trouble wrapping my head around one concept: under this model, the present universe expanded (as space itself into a void) almost to its present size, what I guess is referred to as 12.5 give or take billion light years out. BUT if its still expanding, and even more so, speeding up in expansion, no light source should reach us. If it is space moving, then that light source is subject to the same expansion and properties. We should see nothing.
 
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DrRocket

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nova_explored":3nkb38xe said:
Hey, nice video.

You know this makes me reminisce about my perception of expansion theory. And I always had trouble wrapping my head around one concept: under this model, the present universe expanded (as space itself into a void) almost to its present size, what I guess is referred to as 12.5 give or take billion light years out. BUT if its still expanding, and even more so, speeding up in expansion, no light source should reach us. If it is space moving, then that light source is subject to the same expansion and properties. We should see nothing.

Emphasis added.

Try wrapping your head around this:

According to the currently accepted theory, the universe did not expand into a void. It just expanded. There is nothing into which it expanded since the universe is the whole enchilada. There is no "something else".

The diameter of the universe "now" is at least 93 billion light years.

It is not at all true that no light source should reach us. After all, we do see the sun and some stars. It is true that there are light sources that don't reach us and that may never reach us. As the universe expands and as the rate of expansion increases there may be more and more light sources that don't reach us. But we will probably always be able to see at least our galaxy and the local group with which we are gravitationally bound and which are not receding from us due to the "expansion of space".
 
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kelvinzero

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I am still irritated whenever I hear people barf up the argument: "the universe is big, therefore there must be other planets with life."

Before you can make this statement, you must make some attempt to place a justifiable lower bounds on the probability of life on a given planet that is otherwise earth-like. Any attempt at all would be appreciated.
 
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