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This is an old revision of this page, as edited by 76.66.198.128 (talk) at 04:48, 22 October 2010 (→‎Abell 2218: new section). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

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Timeline?

The article says "The galaxy's image was first captured in the Hubble Ultra Deep Field, the most detailed deep space picture ever taken,[1] by the Hubble telescope's recently-attached Wide Field Camera 3 (WFC3) in August and September of 2009.[3][4]" But HUDF was created in 2003 and 2004, using the Advanced Camera for Surveys put up in March 2002. Wide Field Camera 3 wasn't installed until 2009 on SM4. So which is it? Did they go back over the same field with the new camera, or something else? Somedaypilot (talk) 21:37, 21 October 2010 (UTC)[reply]

Fallacy

"...a galaxy which, as of October 2010, is the most distant object from Earth known to exist in the universe to date."

Isn't there something slightly fallacious in suggesting that this galaxy "exists" in the universe? If it's 13 billion light years away then surely all we can verify is that it existed 13 billion years ago. - filelakeshoe 22:10, 21 October 2010 (UTC)[reply]

How about: "...a galaxy which, as of October 2010, is the most distant object in the universe observed from Earth"? -- Black Falcon (talk) 22:37, 21 October 2010 (UTC)[reply]
Filelakeshoe makes a good point,and I think Black Falcon's revision comes as close as possible to remedying the problem. AGradman / talk / how the subject page
when I made this edit 23:04, 21 October 2010 (UTC)
Yep, that sounds a lot better. - filelakeshoe 23:43, 21 October 2010 (UTC)[reply]

Sorting out the Dark Ages; microwave background transmission from a transparent universe

The article currently says:

The universe's first stars, blue giants, were born out of the once-ubiquitous hydrogen fog, and burned bright but had short lifespans. Their existence created the first heavy elements, and intense ultraviolet radiation split atoms into protons and electrons, clearing the hydrogen fog and producing plasma still detectable between closely neighboring stars.[1][2] The period of opaque space between the Big Bang and this event is referred to as the Dark Ages. The era of star birth which followed is known as the reionization epoch,[3] and lasted from somewhere around 150 million to 800 million years after the Big Bang.[2] Astronomers are trying to pin down when and how the Dark Ages ended.[3] The transparent "bubble" which surrounds UDFy-38135539 proves that 600 million years after the Big Bang, stars in galaxies had almost completed the process of hydrogen reionization which resulted in the end of the Dark Ages,[4] by creating the magnetic field that shaped subsequent galaxies and spurred more star formation.[5]

Now the Dark Ages can't have reached all the way back to the Big Bang, because at 380,000 years the microwave background radiation was emitted at about 3000K. So the Dark Ages have a beginning, which should be explained. (it'd also be interesting to hear how the not-yet-microwaves made it through the Dark Ages, but maybe not relevant. What frequency was it down to by the time the Dark Ages started?)

Also, my impression from the other articles was that the transparency of the universe at this early time was due to the emergence of neutral matter. So wouldn't reionization make it opaque again?

A last detail is that, as I understand from the little section linked, the Dark Ages were actually a "foggy" age, and people are hunting for 21-cm radiation from it. This should come from some sort of "wall" representing something less than 600 million years after the Big Bang. Is there a current consensus about where that wall of 21-cm emission should be, i.e. how much space is "behind" this galaxy, if any (from the article it looks like it may actually be in a sort of cranny in the wall!) Wnt (talk) 23:08, 21 October 2010 (UTC)[reply]

Accuracy of distance

This article states in the Characteristics section that, "It has a light travel distance of more than 4 billion parsecs from our planet[10] (over 13 billion light years), and a luminosity distance of 86.9 billion parsecs (about 283 billion light years)" Neither source 10 or 11 stated the luminosity distance and a distance of 86.9 billion parsecs would put it well beyond the current accepted diameter of the observable Universe (93 billion LY). Given that figure the furthest it could be would be 46.5 billion LY. It seems the media still does not understand the concept of expansion and its effect on spacetime as almost every source lists the distance as 13 billion LY due to the mistaken idea that this is the furthest that light could travel in 13 billion years. That being said I can't find a source that gives a real figure for distance to UDFy-38135539 in parsecs or LY. —Preceding unsigned comment added by 71.226.131.15 (talk) 01:43, 22 October 2010 (UTC)[reply]

"Characteristics" not current, perhaps misleading

"According to Lehnert (of the Observatoire de Paris), it is forming the same number of stars per year as our galaxy, but they are much smaller and less massive, making it "intensely star forming".

Isn't this somewhat misleading, given that we are currently observing photons emitted 13 billion years ago? Any reader not up on cosmology (and I certainly include myself in that group) could take that to mean that we know what the galaxy is currently like and what's currently happening there.

Maybe "13 billion years ago, the galaxy was forming the same number of stars per year as our galaxy is now, but..." And this could perhaps lead into a discussion on why star formation was so different at that time, compared to now, which could lead nicely into the "Significance" section.

Or not. I don't pretend to be well-versed in the issues, and am not about to try an edit, but thought I'd bring it up for discussion amongst editors with more knowledge. 209.217.221.162 (talk) 02:04, 22 October 2010 (UTC)[reply]

Abell 2218

Abell 2218 — location of the previous record holder for most distant galaxy

That's factually incorrect. Abell 2218 is very close by in comparison to IOK-1 and this galaxy. The claim is for a pair of galaxies gravitationally lensed by the cluster, which is not the same thing, since they are not in the same location, they are only coincidentally in the same line of sight. 76.66.198.128 (talk) 04:48, 22 October 2010 (UTC)[reply]

  1. ^ Cite error: The named reference BBC was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Fox was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference DMUK was invoked but never defined (see the help page).
  4. ^ National Geographic: "Universe's Most Distant Object Spotted"
  5. ^ Cite error: The named reference USAToday was invoked but never defined (see the help page).
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