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To-do list for Warm–hot intergalactic medium: edit · history · watch · refresh · Updated 2019-10-10 Here are some tasks awaiting attention: Article requests : It needs a discovery history – how was it found and by whom? Some discussion of metal enrichment history would be of interest.

Wiki Education Foundation-supported course assignment

This article is or was the subject of a Wiki Education Foundation-supported course assignment. Further details are available on the course page. Student editor(s): Britt4298.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 12:40, 17 January 2022 (UTC)

Quanta article 10 May 2018

I'm not sure of the best way to include this, so I'll leave the reference here and let regular editors of this page handle it:

https://www.quantamagazine.org/the-last-of-the-universes-ordinary-matter-has-been-found-20180910/

Michael Kinyon (talk) 16:06, 14 September 2018 (UTC)

Removed on 18 May '15

Notion that the WHIM has been detected based on the following reference: 'Detection and Characterization of the Warm-Hot Intergalactic Medium'

This article has been withdrawn by the authors: http://arxiv.org/abs/1205.5753

WHIM

Why is WHIM so hot?

I saw a reference that WHIM has a temperature of 100,000 to 10 million degrees. How does it stay so hot? (I'm guessing that radiative cooling require the particles to collide before they can slow down and emit the relative motion as photons?) Why was it so hot in the first place? Wnt (talk) 20:53, 17 May 2010 (UTC)

This paper discusses hydrodynamic simulations of the WHIM: . It indicates that the gas is heated and compressed by shocks from gravitationally collapsing regions. There is some mention of cooling, but I gather that the cooling of the WHIM is substantially complicated by feedback, and that a lot of open questions remain in this area. --Amble (talk) 20:27, 21 May 2010 (UTC)

Yes, from the perspective of a layman (like me!), it sounds really odd that ultra-thin gas in open space can be hot. I found this blog answer (and a similar one here), which makes a lot of sense, but is probably not WP-suitable. I hope someone can insert this or a better explanation into this article:
This is related to the fact that low density gas cools itself very inefficiently, because cooling generally requires collisions between the particles (which generates the light). Heating, on the other hand, can occur in various ways that might involve interactions with something other than the particles, say with cosmic rays or with magnetic fields.
Onanoff (talk) 12:32, 5 December 2022 (UTC)

Requested move

Warm–hot intergalactic medium → Warm-hot intergalactic medium – (hyphen instead of en dash). That's what all sources I was able to find use (except one which uses a slash); it is a medium with an intermediate temperature (cf blue-green algae with a hyphen), not one with two components with different temperatures (cf red–green colorblind with a dash). ― A. di M.​_plé​ 00:34, 5 August 2011 (UTC)

Hyphen Very few users will be able to see any difference between a hyphen and an en-dash, and I think the distinction in meaning between the two is in the nominator's imagination. However, a hyphen appears on a standard keyboard and an en-dash does not. Throw in a redirect in the miraculous event that someone actually bothers to type an en-dash. D O N D E groovily Talk to me 03:56, 5 August 2011 (UTC)

Oppose – that is, stay with the en dash. Nobody is asking anyone to type it (which is something that only Mac users do, apparently); hyphen will work for that via the existing redirect. And if very few users will be able to see the difference, the move would do them no good. So, if there is a distinction in meaning, we should determine the correct title by those who do see the difference and do understand the meaning. When I think en dash conveys the meaning better, I always check to make sure I can find a couple of good sources to back that up. They do exist in this case, in Nature and Royal Astron. Soc., for instance. Many authors don't follow the same style we do, but in WP when the en dash is appropriate, that's what we choose. The slash is also a dead giveaway that some authors are aware that a hyphen does not convey the right sense. It's not totally clear what the intended sense is, but appears that "warm to hot" is closer than "warmish-hot". Even Ostriker, who coined the term in 1999, says in 2000: "This diffuse gas is also known as the warm/hot intergalactic medium (WHIM). It is located outside of clusters of galaxies and is heated to temperatures, T = 10 – 10K, intermediate between those of the hot cluster gas and the warm gas in voids." As far as I can find, he uses warm/hot, but not the full phrase, in all his 1999 papers. This range of 2 orders of magnitude in temperature seems more like a "range" than a point between warm and hot, doesn't it? He clearly didn't intend the meaning suggested by a hyphen. Dicklyon (talk) 05:09, 5 August 2011 (UTC)

Err, let me get this right: it is a medium that is "from warm to hot", yes? Not warmish/hottish. If that is the case, the en dash is necessary. Tony (talk) 05:30, 5 August 2011 (UTC)

Yes, that's my point. Dicklyon (talk) 05:55, 5 August 2011 (UTC)

Oppose per refs. A slash, properly used, would mean 'warm or hot', approximately equivalent to 'warm to hot'. The fact that Nature bothers with the en dash suggests that they really don't want people thinking it's a warmish-hot medium. — kwami (talk) 06:36, 5 August 2011 (UTC)

Nomination withdrawn. WTH? I swear the one in Nature looked like a hyphen last night, but maybe it's just me who shouldn't be editing after 2 a.m. ― A. di M.​_plé​ 11:53, 5 August 2011 (UTC)

So what is it?

I just read all this article and I'm still not clear on what WHIM actually is? In layman's terms please? — Preceding unsigned comment added by 212.139.233.75 (talk) 23:00, 25 May 2012 (UTC)

It's a very diffuse cloud of heated particles that lies in between galaxies. Praemonitus (talk) 18:26, 10 October 2019 (UTC)

I want to add information from http://iopscience.iop.org/article/10.1086/320548/meta and http://www.space.com/8386-huge-chunk-universe-missing-matter.html and a picture from http://www.astro.princeton.edu/~cen/PROJECTS/p1/GASallz0.jpeg Britt4298 (talk) 17:04, 21 November 2016 (UTC) Brittany

It says WHIM consists of or contains much of "the baryonic 'normal matter'". But, is it believed that WHIM contains largely of protons, helium cores, and maybe some neutrons and other "normal" atom nuclei (all of these usually ionized ?), or are there a lot of other baryons present, unlike the matter we are familiar with on earth? Meerwind7 (talk) 21:11, 19 November 2022 (UTC)

Intracluster medium

Does this overlap with Intracluster medium? --JWB (talk) 17:01, 24 June 2020 (UTC)

Using fast radio bursts (FRBs) dispersion as proof of the existence of the WHIM

This article seems related, useful, and interesting. I don't know enough about astronomy to know whether it should be included in the article, or how to summarize it well enough to fit in, but I thought I'd leave it here for other editors to find. rchard2scout (talk) 08:24, 4 August 2020 (UTC)

References

1. Prochaska, J. Xavier; Macquart, Jean-Pierre (29 May 2020). "Half the matter in the universe was missing – we found it hiding in the cosmos". The Conversation. Archived from the original on 4 August 2020. Retrieved 4 August 2020.

Clash with Baryon article

This article says that the Warm-hot intergalactic medium contains 40-50% of the normal baryonic matter in the universe. But the article on Baryons says that 30-40% of baryons are in the Warm-hot intergalactic medium. Do this figures contradict each other, or is there a distinction which means that they don't? I know nothing about the subject so have changed neither article. But perahps some clarification is needed. Sbishop (talk) 18:11, 2 September 2020 (UTC)Sbishop

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