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The observable universe

by BOAS
Tags: observable, universe
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KyleScott
#19
Oct11-13, 02:05 PM
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Quote Quote by phinds View Post
No, if it were 1 million LY from the edge of the observable universe, the light would not arrive here for something like 49 BILLION light years.
Allow me to clarify: a million years from now.

And what do you mean that it would arrive in 49 billion LIGHT-years? lol
phinds
#20
Oct11-13, 02:43 PM
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Quote Quote by KyleScott View Post
Allow me to clarify: a million years from now.

And what do you mean that it would arrive in 49 billion LIGHT-years? lol
Yep, I blew that one. I meant 47 billion years, not LY. That's how long it will take a new photon from the edge of the observable universe to reach the Earth.
Chronos
#21
Oct11-13, 03:13 PM
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Actually, light emitted TODAY from a body a million light years in the foreground of the CMB will NEVER get here. z~1.7 is the maximum distance from which a photon emitted NOW is capable of reaching earth. See Lineweaver and Davis - Expanding Confusion.
Fermifaq
#22
Nov25-13, 12:44 AM
P: 15
was reading up on this the other day and found this useful

Comoving distance
http://en.wikipedia.org/wiki/Comoving_distance

Hubble volume
http://en.wikipedia.org/wiki/Hubble_volume

In cosmology, a Hubble volume, or Hubble sphere, is a spherical region of the Universe surrounding an observer beyond which objects recede from that observer at a rate greater than the speed of light due to the expansion of the Universe



"The Real Universe" --'Is 250 Times Bigger than the Visible Hubble Volume'
http://www.dailygalaxy.com/my_weblog...popular-1.html

Observable_universe
http://en.wikipedia.org/wiki/Observable_universe



As the universe gets older, and our light cone gets larger we will start to see a bit more of the universe that is currently hidden from us, but some stuff will permanently remain out of view.

There is also something called the 'lookback time'
http://en.wikipedia.org/wiki/Redshift#Highest_redshifts
Chronos
#23
Nov25-13, 01:57 AM
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I assume you had a point, unfortunately I didn't get it.


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