Expansion and light reaching Earth Question

[beskeptical]

We're collecting light that left other parts of the Universe 14 billion years ago:
http://www.space.com/scienceastronomy/subaru_starburst_020823.html
And the Universe is expanding.

While we may not be able to see back to the earliest time in the Universe's beginning, what can we see beyond the time light has had to travel?

In other words, isn't there some place out there where it is dark beyond? Not because it's the edge of the Universe, but because it's the edge of the light that has had time to reach us?

Will there be light from some galaxy blocking every viewpoint?

Could we be seeing that darkness now but not be able to recognize that's what it is?

I've seen the picture with all the galaxies in the Hubble deep field photo. Can the Hubble be trained on a dark spot from that pic or do we have to wait for bigger/better scopes?

Guess I'm contemplating the Universe again.

Hey, there's a new box here for email alerts. /phpBB/images/smiles/icon_smile.gif

[Silas]

As I understood it, the 3-degree background microwave radiation *is* the ultimate darkness of the BB, the fireball itself, that has cooled down a bit.

Standard BB theory divides the early cosmos into an energy-dominant phase and a matter-dominant phase. The former would be opaque to light, and thus we can never see through it or even into it.

And, of course, the expansionary phase model suggests that we can never see beyond the very small region of our own isolated part of the cosmos...

Silas

[traztx]

On 2002-08-27 11:20, Silas wrote:
...the very small region of our own isolated part of the cosmos...


Heh... the phrase "very small" is certainly relative. Reminds me of "the vortex" from one of Douglas Adams books. The ultimate torture chamber where you are able to see the entire universe and there is a little sign: "you are here".

[Wiley]

On 2002-08-27 04:04, beskeptical wrote:
While we may not be able to see back to the earliest time in the Universe's beginning, what can we see beyond the time light has had to travel?

In other words, isn't there some place out there where it is dark beyond? Not because it's the edge of the Universe, but because it's the edge of the light that has had time to reach us?


Yep. This is the particle horizon; beyond the particle horizon there has been no interaction between us and them. Which means that light from them has never reached us and vice-versa. I believe most cosmologist think that most of the universe is beyond this horizon, but since we have no information about it, we really don't know.



Will there be light from some galaxy blocking every viewpoint?

As long as the visible universe is finite, I think the answer is no. As the universe ages and the visible universe expands, the sky will be more "cluttered", but will never be "full". This is kinda of the converse (or is it inverse?) of Olber's paradox (http://astrosun.tn.cornell.edu/courses/astro201/olbers_paradox.htm).



Could we be seeing that darkness now but not be able to recognize that's what it is?

I am not sure I understand the question. The darkness is really light that has not reached us yet. When the light reaches we can glean information about it, but not until then.



Guess I'm contemplating the Universe again.

Nothing wrong with that unless, of course, your boss catches you. /phpBB/images/smiles/icon_smile.gif

<font size=-1>[ This Message was edited by: Wiley on 2002-08-27 12:30 ]</font>

[beskeptical]

On 2002-08-27 12:29, Wiley wrote:
Yep. This is the particle horizon; beyond the particle horizon there has been no interaction between us and them. Which means that light from them has never reached us and vice-versa. I believe most cosmologist think that most of the universe is beyond this horizon, but since we have no information about it, we really don't know.


Could we be seeing that darkness now but not be able to recognize that's what it is?

I am not sure I understand the question. The darkness is really light that has not reached us yet. When the light reaches we can glean information about it, but not until then.



Guess I'm contemplating the Universe again.

Nothing wrong with that unless, of course, your boss catches you. /phpBB/images/smiles/icon_smile.gif

Fortunately, I am the boss. Have had my own practice for 12 years now. /phpBB/images/smiles/icon_biggrin.gif Besides, I'm not at work, my office is on the other side of the house. /phpBB/images/smiles/icon_biggrin.gif

Thanks for the insight though. I shall continue contemplating with that added piece.