Talk:ULAS J1120+0641

Most distant?

I'm not sure it's the most distant object ever observed, there are at least 2 others more distant. I think it's the most distant quasar ever discovered, and it appears to be the brightest. [1] So I think it should be noted as the brightest object and the most distant quasar. I'll change it but if that's wrong we might need to work out what the sources are saying. RxS (talk) 04:07, 30 June 2011 (UTC)

Clearly you're right -- I've fixed a couple more occurrences of the error as well, changing "object" to "quasar". Looie496 (talk) 04:22, 30 June 2011 (UTC)

Thanks. RxS (talk) 04:25, 30 June 2011 (UTC)

As of 2015, this is still the most distant quasar known. [2] -- 67.70.32.190 (talk) 08:27, 11 August 2015 (UTC)

Distance and age of the universe

I corrected the distance, the previous version said about 28 billion lightyears away, the age of the universe is 13,7 billion years so I recalculated the redshift with the calculator I linked in and got a more fitting distance about 12 billion light years. If I´m wrong correct me but I´m sure a quasar can´t be twice as far away as the universe is old (regards, Yukterez - Yukterez) —Preceding undated comment added 23:24, 30 June 2011 (UTC).

Sorry, that's not correct. The lookback time is 12 Gyr, but the (comoving) distance to redshift 7 is 28 Gly. The universe has expanded since the light left the quasar, so the distance the light has covered is more than just the lookback time times the speed of light. - Parejkoj (talk) 23:37, 30 June 2011 (UTC)

If the Big Bang happened 13 billion years ago and expansion in Euclidean space is taking place more or less symmetrically, according to the principle that 1+1=2, my arithmetic says there can't be any two objects in the Universe more than 26 billion light years apart. Either the estimate of the age of the Universe is way off, or the distance of ULAS J1120+0641 is nonsense. — Quicksilver^{T @} 15:49, 1 July 2011 (UTC)

The Universe doesn't have a Euclidean metric. See Distance measures (cosmology), Comoving distance and Metric expansion of space for more about this. - Parejkoj (talk) 15:58, 1 July 2011 (UTC)

I nearly set out to correct the distance myself, until I happened across this discussion. Given that most non-cosmologists aren't aware of this distance issue, a footnote explaining the matter to readers would be a good idea. --Colin Douglas Howell (talk) 19:03, 1 July 2011 (UTC)

Ah, I see it's in the text (though it could be a bit more descriptive rather than a simple "look here"); how about a footnote for the Infobox? --Colin Douglas Howell (talk) 19:06, 1 July 2011 (UTC)

Anybody to explain with a short calculus the differnce between the distance (28 Glightyr) and the age of universe (say 13 Gyr) or refer to a relevant article ? — Preceding unsigned comment added by 82.232.197.117 (talk) 17:40, 15 February 2016 (UTC)

See Distance measures (cosmology), particularly the second figure there. 28 Gly is the comoving distance, whilst you're thinking of the lookback time. Modest Genius ^talk 11:45, 16 February 2016 (UTC)

Luminosity dispute

The article presently says that the AP says it's the most luminous quasar but they're wrong... However the source given for why AP is wrong is a 2007 paper. I'm afraid this is a case of "original research". Can a source be found that says that the AP is wrong about this quasar? Please? It would be much more proper. Wnt (talk) 17:04, 1 July 2011 (UTC)

Well, the 2007 paper shows there are many quasars with luminosities of 10^15. This quasar has a luminosity of 10^13, so clearly cannot be the brightest. Neither the paper itself, nor the press releases from ESO, Nature etc. make the claim. No idea if there's a source which explicitly states that the AP is wrong, but it clearly is. I think this is a case of weighing up contradictory statements between different sources, rather than original research. I agree an explicit statement by a reliable source would be better, but can't imagine anyone bothered to publish such a thing (there might be blog posts or something though).

As an analogy, if a news report had said person X was aged 58, but person X's own website and other reliable sources all said they were in fact aged 48, would we require a source that explicitly said that the 58 was wrong? No, we would not, and just take the correct age from the sources. Modest Genius ^talk 20:49, 1 July 2011 (UTC)

Which constellation?

So which constellation is this quasar located in? I have not seen it mentioned in any of the sources used (even the Nature article that announced the finding). Are they trying to keep it secret? Not sure why, if they have published their findings... I tried using an RA/Dec calc program; but it only gave me more precise coordinates... I think we should mention in the wiki article what constellation it's located in for general interest.--FeanorStar7 (talk) 10:48, 2 July 2011 (UTC)

Well given that the article is named for where it is in the sky, they're doing a pretty poor job of keeping it secret. I don't know a website where you can convert right ascension and declination to the constellation, but I'm sure it exists. -RunningOnBrains^(talk) 20:32, 2 July 2011 (UTC)

It's in Leo, not far from σ Leo. I'll add that, but it's unsourced (I just read it off this star chart). Modest Genius ^talk 21:58, 2 July 2011 (UTC)

Thanks; I checked WikiSky and it looked like it was in Leo or on the border with Virgo.--FeanorStar7 (talk) 00:46, 3 July 2011 (UTC)

Significance

> The light from ULAS J1120+0641 was emitted during a time period before the end of the theoretically predicted transition of the intergalactic medium from an electrically neutral to an ionized state.

Shouldn't this be the other way around? --185.189.112.19 (talk) 21:50, 27 October 2017 (UTC)

Nope, see reionisation. I've tried to rephrase this passage to make the logic clearer. Modest Genius ^talk 13:16, 30 October 2017 (UTC)

"Four direct measurements of the fine-structure constant 13 billion years ago"

Some short information on this paper should probably be added to the article (under the section "Significance").

I have added this to the article 2020 in science:

• Scientists report verifying measurements 2011-2014 of what seem to be discrepancies in four measurements of the fine-structure constant, a basic physical constant used to measure electromagnetism between charged particles, which indicates that there might be directionality with varying natural constants in the Universe which would have implications for theories on the emergence of habitability of the Universe and be at odds with the widely accepted theory of constant natural laws and the standard model of cosmology which is based on an isotropic Universe.

--Prototyperspective (talk) 13:07, 23 May 2020 (UTC)

References