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Astronomers uncover oldest galaxy so far (13.2 billion light years)



 
 
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  #1  
Old September 19th 12, 11:14 PM posted to sci.physics,sci.astro
Yousuf Khan[_2_]
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Posts: 1,692
Default Astronomers uncover oldest galaxy so far (13.2 billion light years)

Astronomers uncover oldest galaxy far, far away | smh.com.au
http://m.smh.com.au/technology/sci-t...920-267iu.html
  #2  
Old September 20th 12, 12:50 AM posted to sci.physics,sci.astro
GogoJF
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Default Astronomers uncover oldest galaxy so far (13.2 billion light years)

On Sep 19, 5:14*pm, Yousuf Khan wrote:
Astronomers uncover oldest galaxy far, far away | smh.com.auhttp://m.smh.com.au/technology/sci-tech/astronomers-uncover-oldest-ga...


What about those stars, star systems, or galaxies in the background of
this picture. How far away do you think they are?
  #3  
Old September 20th 12, 12:53 AM posted to sci.physics,sci.astro
GogoJF
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Default Astronomers uncover oldest galaxy so far (13.2 billion light years)

On Sep 19, 6:50*pm, GogoJF wrote:
On Sep 19, 5:14*pm, Yousuf Khan wrote:

Astronomers uncover oldest galaxy far, far away | smh.com.auhttp://m.smh.com.au/technology/sci-tech/astronomers-uncover-oldest-ga...


What about those stars, star systems, or galaxies in the background of
this picture. *How far away do you think they are?


When we get to the "end"- where we can "see" with our devices the
limit of the big bang- will the background be all black? I doubt it.
  #4  
Old September 20th 12, 03:29 AM posted to sci.physics,sci.astro
Yousuf Khan[_2_]
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Default Astronomers uncover oldest galaxy so far (13.2 billion lightyears)

On 19/09/2012 7:50 PM, GogoJF wrote:
On Sep 19, 5:14 pm, Yousuf wrote:
Astronomers uncover oldest galaxy far, far away | smh.com.auhttp://m.smh.com.au/technology/sci-tech/astronomers-uncover-oldest-ga...


What about those stars, star systems, or galaxies in the background of
this picture. How far away do you think they are?


That picture is not an actual picture of the galaxy in question. If you
read the caption on the picture that's a picture of a galaxy named, NGC
1365, which is just being used as a representation of that this galaxy
might look like. A galaxy that far away would be only a couple of pixels
in an actual image.

Yousuf Khan
  #5  
Old September 20th 12, 03:30 AM posted to sci.physics,sci.astro
GogoJF
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Posts: 33
Default Astronomers uncover oldest galaxy so far (13.2 billion light years)

On Sep 19, 9:29*pm, Yousuf Khan wrote:
On 19/09/2012 7:50 PM, GogoJF wrote:

On Sep 19, 5:14 pm, Yousuf *wrote:
Astronomers uncover oldest galaxy far, far away | smh.com.auhttp://m.smh.com.au/technology/sci-tech/astronomers-uncover-oldest-ga...


What about those stars, star systems, or galaxies in the background of
this picture. *How far away do you think they are?


That picture is not an actual picture of the galaxy in question. If you
read the caption on the picture that's a picture of a galaxy named, NGC
1365, which is just being used as a representation of that this galaxy
might look like. A galaxy that far away would be only a couple of pixels
in an actual image.

* * * * Yousuf Khan


Thank you.
  #6  
Old September 21st 12, 08:41 AM posted to sci.physics,sci.astro
Mike Dworetsky
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Default Astronomers uncover oldest galaxy so far (13.2 billion light years)

GogoJF wrote:
On Sep 19, 5:14 pm, Yousuf Khan wrote:
Astronomers uncover oldest galaxy far, far away |
smh.com.auhttp://m.smh.com.au/technology/sci-tech/astronomers-uncover-oldest-ga...


What about those stars, star systems, or galaxies in the background of
this picture. How far away do you think they are?


The journalists used an image of a nearby galaxy as an illustration. In the
actual images shown in the Nature article, the galaxy MACS 1149-JD is just a
blob of a few pixels extent. As the object is visible only because it is
gravitationally lensed (hence looks much brighter than it would otherwise
appear) all the other objects in the field are either nearer galaxies or
foreground stars in our galaxy.

What is really interesting is that the spectrum (or, rather, multi-colour
photometry) shows that it is a starburst galaxy and an analysis of the
stellar populations implies that the stars in the galaxy were mostly formed
within 200 MYr of the Big Bang, although that conclusion is only 2-sigma
confidence. The implication is that galaxies were forming and stars were
forming only 200 MYr after the BB.

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

  #7  
Old September 21st 12, 03:26 PM posted to sci.astro
dlzc
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Default Astronomers uncover oldest galaxy so far (13.2 billion light years)

Dear Mike Dworetsky:

On Friday, September 21, 2012 12:41:49 AM UTC-7, Mike Dworetsky wrote:
....
As the object is visible only because it is
gravitationally lensed (hence looks much brighter
than it would otherwise appear) all the other
objects in the field are either nearer galaxies or
foreground stars in our galaxy.


When an object of some "standard" size, is located in a much smaller Universe, the image travels out into an expanded Universe, the original object appears magnified... but it was expansion that did it, not gravitation, right? Objects don't stretch with the "balloon", but the image does.

How does intensification occur when climbing out of a gravity well (from a more dense Universe, into a less dense Universe)? It would make more sense to me that the object was more massive, and was still getting hotter CMBR light to pump photoactivity, so its intensity would have nothing to do with gravitational lensing.

David A. Smith
  #8  
Old September 21st 12, 05:19 PM posted to sci.astro
Mike Dworetsky
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Posts: 715
Default Astronomers uncover oldest galaxy so far (13.2 billion light years)

dlzc wrote:
Dear Mike Dworetsky:

On Friday, September 21, 2012 12:41:49 AM UTC-7, Mike Dworetsky wrote:
...
As the object is visible only because it is
gravitationally lensed (hence looks much brighter
than it would otherwise appear) all the other
objects in the field are either nearer galaxies or
foreground stars in our galaxy.


When an object of some "standard" size, is located in a much smaller
Universe, the image travels out into an expanded Universe, the
original object appears magnified... but it was expansion that did
it, not gravitation, right? Objects don't stretch with the
"balloon", but the image does.

How does intensification occur when climbing out of a gravity well
(from a more dense Universe, into a less dense Universe)? It would
make more sense to me that the object was more massive, and was still
getting hotter CMBR light to pump photoactivity, so its intensity
would have nothing to do with gravitational lensing.

David A. Smith


It is gravitationally lensed by a giant elliptical galaxy in a dense cluster
between us and the distant galaxy, which is why it looks a lot brighter than
it would if there were no lensing. In fact it would be invisible to HST.
The cluster and giant galaxy are both much closer to us than the very
distant object.

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

  #9  
Old September 21st 12, 06:20 PM posted to sci.astro
dlzc
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Posts: 1,426
Default Astronomers uncover oldest galaxy so far (13.2 billion light years)

Dear Mike Dworetsky:

On Friday, September 21, 2012 9:19:31 AM UTC-7, Mike Dworetsky wrote:
....
It is gravitationally lensed by a giant elliptical
galaxy in a dense cluster between us and the
distant galaxy, which is why it looks a lot brighter
than it would if there were no lensing. In fact it
would be invisible to HST.

The cluster and giant galaxy are both much closer to
us than the very distant object.


Focus, as in bending light rays destined for a larger area, to a smaller one.

Got it. Thanks.

David A. Smith
  #10  
Old September 21st 12, 08:04 PM posted to sci.astro
John Polasek[_2_]
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Posts: 2
Default Astronomers uncover oldest galaxy so far (13.2 billion light years)

On Fri, 21 Sep 2012 10:20:30 -0700 (PDT), dlzc wrote:

Dear Mike Dworetsky:

On Friday, September 21, 2012 9:19:31 AM UTC-7, Mike Dworetsky wrote:
...
It is gravitationally lensed by a giant elliptical
galaxy in a dense cluster between us and the
distant galaxy, which is why it looks a lot brighter
than it would if there were no lensing. In fact it
would be invisible to HST.

The cluster and giant galaxy are both much closer to
us than the very distant object.


Focus, as in bending light rays destined for a larger area, to a smaller one.

Got it. Thanks.

David A. Smith

Why didnt they mention the redshift z? You can't estimate distance
without it.
 




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