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EvC Forum ⇒ Science Forums ⇒ Big Bang and Cosmology ⇒

Question About the Universe

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Author Topic:   Question About the Universe
Blue Jay
Member (Idle past 2891 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008

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Message 6 of 373 (506871)
04-29-2009 11:45 PM 		Reply to: Message 1 by GDR
04-29-2009 3:46 PM

Expansion and the Movement of Light
Hello, GDR.
​
I'm not even going to pretend I can answer your question. Rather, I'm going to add to it, to make it more confusing.
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If the universe has been expanding since the Big Bang, wouldn't this mean that a star 13 billion lightyears away was less than 13 billion lightyears away at a time closer to the Big Bang?
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So, would it still have taken the light 13 billion years to get here from there?
Or, if it was 10 billion lightyears closer at the time of its formation, would the light have reached here 10 billion years earlier?
​
-Bluejay/Mantis/Thylacosmilus
​
Darwin loves you.
This message is a reply to:
 Message 1 by GDR, posted 04-29-2009 3:46 PM GDR has replied
Replies to this message:
 Message 7 by GDR, posted 04-30-2009 12:39 AM Blue Jay has replied
 Message 12 by cavediver, posted 04-30-2009 2:29 PM Blue Jay has not replied
  
Blue Jay
Member (Idle past 2891 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008

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Message 8 of 373 (506900)
04-30-2009 9:16 AM 		Reply to: Message 7 by GDR
04-30-2009 12:39 AM

Re: Expansion and the Movement of Light
Hi, GDR.
​
GDR writes:
​
I believe, that although the star would have been closer in the past it doesn't change the fact that the light from that star that was recently viewed left it 13 billion years ago.
​
If the expansion of the universe is slower than the speed of light, shouldn't it have been able to shave off at least a little bit of the transit time?
​
-Bluejay/Mantis/Thylacosmilus
​
Darwin loves you.
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 Message 13 by cavediver, posted 04-30-2009 2:35 PM Blue Jay has replied
  
Blue Jay
Member (Idle past 2891 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008

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Message 14 of 373 (506969)
04-30-2009 2:50 PM 		Reply to: Message 13 by cavediver
04-30-2009 2:35 PM

Re: Expansion and the Movement of Light
Hi, Cavediver.
​
cavediver writes:
​
Any uniform expansion rate, over a sufficient distance, creates a "superluminal" expansion.
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Okay. So, is the expansion rate uniform, or close enough to it to get away with saying it is?
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It also seems that, if each kilometer is thought of as expanding over a period of time, wouldn't much of the expansion between us and the other star be happening behind the light as it traveled? To my mind, this means that any light we're seeing didn't actually travel the entire distance from there to here.
​
Am I leaving something out?
It seems like I'm making it harder than it needs to be.
​
-Bluejay (a.k.a. Mantis, Thylacosmilus)
​
Darwin loves you.
This message is a reply to:
 Message 13 by cavediver, posted 04-30-2009 2:35 PM cavediver has replied
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