Talk:GW190521

Created talk-page
Created talk-page for the "GW190521g" article - Enjoy! :) - and - Stay Safe and Healthy !! - Drbogdan (talk) 02:03, 26 June 2020 (UTC)

ITN discussion
If interested, ITN discussion at => In the news/Candidates - Drbogdan (talk) 01:24, 4 September 2020 (UTC)

7 billion years ago
The article in the New York Times says "7 billion years ago" in two spots and "17 billion light-years away" in one spot that I saw. One might assume that "7 billion years ago" implies "7 billion light years away," because gravitational waves travel at the speed of light. The waves were emitted from a distance of 7 billion light years at a time 7 billion years ago. In the intervening seven billion years of elapsed time, the Universe expanded and the location of the event, previously at a distance of 7 billion light years, is _now_ at a distance of 17 billion light years (the meanings of _ago_, _now_, and _distance_ are not trivial, requiring careful calculations in standardized cosmological coordinate systems and reference frames). 97.113.128.35 (talk) 15:05, 5 September 2020 (UTC)
 * Note that there are two different New York Times articles cited, and each gives a different number of billions of years. Neither appear to be taken directly from any scientific paper; the closest I came was "about half the age of the universe", which an avid newspaper journalist might well interpret at seven billion years.  The point is moot for now: I removed the statement completely some time ago because the given reference did not give a number of years, and certainly not seven billion.  Someone might wish to write a more complete explanation in the body of the article and then, perhaps, give a headline number in the lead.  Lithopsian (talk) 19:41, 6 September 2020 (UTC)
 * FWIW - one of the original research papers notes "5.3 Gpc", which converts to "17,286,290,363.516422 light-years" - hope this helps - iac - Stay Safe and Healthy !! Drbogdan (talk) 13:12, 15 September 2020 (UTC)

17 BILLION light years?
How can this be 17 BILLION light years away when that's greater than the age of the universe? -- Veggies (talk) 13:49, 4 September 2020 (UTC)
 * The universe expands. Nick Levine (talk) 14:09, 4 September 2020 (UTC)

Thank you for your Question - this NYT quote may also help => "The event unfolded at an almost unimaginable distance from Earth — in a spot that is now 17 billion light-years away according to standard cosmological calculations that describe an expanding universe." - in any case - Stay Safe and Healthy !! - Drbogdan (talk) 14:13, 4 September 2020 (UTC)
 * It should be added to List of the most distant astronomical objects, then. I can't say I comprehend something being beyond the observable limit. -- Veggies (talk) 14:36, 4 September 2020 (UTC)
 * I agree Veggies, this would definitely warrant being placed on the List of the most distant astronomical objects as it appears it would be the most distant astronomical object on the whole list. I also found this link explaining the theory of an expanding universe, "The expanding Universe" I believe this is only a theory as there seems to be competing theories as well. Jurisdicta (talk) 15:40, 4 September 2020 (UTC)
 * Radius of the observable universe currently about 46 billion light years. Lithopsian (talk) 19:10, 4 September 2020 (UTC)
 * I'm certainly not disputing any of this. It's just extremely difficult for me to comprehend it at this point. -- Veggies (talk) 14:42, 5 September 2020 (UTC)

That is possibly a typo. This article says Seven billion. https://www.bbc.com/news/science-environment-53993937 Mr. 123453334 (talk) 23:35, 14 September 2020 (UTC)
 * and others - No - seems the BBC News article may have the typo instead - after all - one of the original research papers notes "5.3 Gpc", which converts to "17,286,290,363.516422 light-years" - hope this helps - iac - Stay Safe and Healthy !! Drbogdan (talk) 13:00, 15 September 2020 (UTC)

The 5.3 Gpc number is coming from the original paper, but it is not the "distance", it is the "luminosity distance". The luminosity distance is very different from the actual distance. Journalists probably took the luminosity distance number and confused it for the actual distance. GehNgiS (talk) 13:49, 8 August 2021 (UTC)

I contacted R. Abbott (the first author in the paper) who was kind enough to get me an answer from one of his colleagues.

They confirmed that the red shift must be taken into account and they pointed me to an online calculator: http://www.astro.ucla.edu/~wright/DlttCalc.html

In this calculator, if you enter "7.05" for "light travel time in Gyr" and click on "flat", the calculator will give "The luminosity distance DL is 5302.7 Mpc or 17.295 Gly."

To sum it up, the observed luminosity distance is 5.3 Gpc or 17.3 billion light-years. However, this is not the actual distance. This 5.3 Gpc luminosity distance, assuming the universe is flat, means that the light/gravity waves traveled for 7.05 billion years, which gives a distance of 7.05 billion light-years. GehNgiS (talk) 19:17, 11 August 2021 (UTC)

Start-Class
What if anything do we need to do, for this article to be rated better than Start-class? Nick Levine (talk) 02:27, 9 September 2020 (UTC)
 * Probably not much. However, I'd suggest writing a section about the event in the title of the article.  Currently we have a section about how amazing it is, and one about the optical counterpart, but I think the title of the article deserves some sort of section about what it actually is (or was), and maybe how it was observed.  I know there is a bit crammed into the lead, but expand it in its own section.  Then you can also ditch most of the refs cluttering up the lead and scaring off half the people that might read it.  Lithopsian (talk) 17:07, 9 September 2020 (UTC)

Template:refn
I introduced this template earlier today, so that note 1 could contain a citation reference. Since then the iOS app has been unable to display the page. All web browsers I tested on are fine with it.

Do we care? Shall I undo my earlier change? Does anyone know of a better way round this?

(I have written to the app maintainers. I don't know whether we can expect a speedy response.)

Nick Levine (talk) 16:45, 9 September 2020 (UTC)
 * For my part - and with one of my present PC systems (dell5770laptop/wintel10/chrome+brave+firefox+opera+edge/latestVersions) - the notes (1/ref+2) on the main article page display *very well* - no problem whatsoever - hope this helps in some way - iac - Stay Safe and Healthy !! - Drbogdan (talk) 17:02, 9 September 2020 (UTC)
 * It’s behaving now. No explanation. Nick Levine (talk) 07:57, 10 September 2020 (UTC)

ITN blurb is currently not mentioned nor referenced in the article
The already-posted ITN blurb says However, the article currently only mentions that these black holes are in the mass gap, but it does not directly say that this was the first detection of a black hole in the upper mass gap. Could someone reference and add the actual ITN claim into the article?

Pinging the ITN-posting admin and editors actively involved in updating the article ( & ). — MarkH21talk 09:22, 14 September 2020 (UTC)


 * FWIW - seems relevant ITN references, discussion and all may be at the following link => https://en.wikipedia.org/wiki/Wikipedia:In_the_news/Candidates/September_2020#(Posted)_GW190521 - hope this helps in some way - iac - Stay Safe and Healthy !! - Drbogdan (talk) 12:49, 14 September 2020 (UTC)
 * I think the “upper” is probably wrong. BH is in the mass gap, but not enormously so. Can we rather update the ITN blurb? Nick Levine (talk) 19:03, 14 September 2020 (UTC)
 * No longer on ITN. Nick Levine (talk) 06:18, 17 September 2020 (UTC)

Confirmation of EM counterpart?
The article states: "If this explanation is correct, the flare should repeat after about 1.6 years". That moment was November/December 2020, was it observed?

--Frdp (talk) 10:33, 11 June 2021 (UTC)