Talk:Sun dog: Difference between revisions

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This article is within the scope of WikiProject Physics, a collaborative effort to improve the coverage of Physics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.PhysicsWikipedia:WikiProject PhysicsTemplate:WikiProject Physicsphysics articles B This article has been rated as B-class on Wikipedia's content assessment scale. Low This article has been rated as Low-importance on the project's importance scale.

Recently someone added a sentence about "sunbows", which allegedly involve sunlight passing through "vapor or mist". This is (a) questionable, as I've never even heard the term "sunbow", in contrast to "glory", "fogbow", and similar well-known optical phenomena, (b) irrelevant to the present article, as it does not refer to the same phenomenon as "sundog", which invariably involves ice crystals and has a different appearance, and (c) technically incorrect, because "vapor" is a gas, invisible and has no optical consequences whatsoever. I'm therefore deleting the sentence in question. Gpetty 15:37, 8 September 2007 (UTC)[reply]

Snow is ice (if you compress snow without melting it will compact to ice as occurs often at the bottom part of a snow pack towards the end of winter), and super cooled water droplets do not necessarily turn to ice at 0 C. Since they are so small the probability of nucleation occuring in the droplet is also small so that they usually remain liquid well below freezing. Nearly pure bulk water freezes at around 0 C because a single nucleation event is highly probable somewhere in the water. Once there is an ice nuclei, it starts a domino effect where nearby water molecules accumulate around it and so on until the entire thing is frozen. You can prevent freezing in bulk water at 32 C by keeping the water in motion which often occurs in waterfalls and rapidly moving streams. For them to freeze the temperature usually has to be well below 15 F for quite a while.

I think the reason sundogs are more commonly seen during winter is because the sun sets earlier, it spends more time near the horizon (which is needed to see a sundog), skies tend to be less cloudy and hazy across large chunks of North America and Asia, and cirrus occur at lower levels, so they are more likely to be seen in front of a setting sun.

In light of this, I think that the page should be updated so that it does not claim that sundogs are winter phenomena.

"it is only produced in clouds cold enough to be ice rather than water, which only occurs far below 0°C."

I'm a little confused, there is no water below zero degrees. Water freezes (and turns to snow) at zero degrees, not far below. In fact most clouds that high are frozen, even in summer. Perhaps the author meant "cold enough to be ice rather than snow".

At any rate, Personal observations tells me that sun dogs only appear on very cold days.

(William M. Connolley 09:51, 24 Feb 2005 (UTC)) Water clouds will remain super-cooled down to quite low temperatures. Absolutely pure water droplets won't spontaneously freeze until it gets to something like -40 oC (I forget the exact number). Air containsCCNs so I think water droplets in the atmos tend to freeze at about -20 oC ish.

Almost correct: It's not CCNs (cloud condensation nuclei) that cause supercooled droplets to freeze, but rather so-called ice nuclei (IN), which can trigger ice formation at various temperatures depending on particle composition, size, etc. Usually IN won't cause a cloud to fully glaciate; therefore pure ice (cirriform) clouds are usually found only at temperatures colder than -40. Sundogs may occur in any weather, any season, as long at the clouds contain ice particles of the right shape. Note also that sundog is spelled as one word by most meteorologists. - Gpetty 15:28, 8 September 2007 (UTC)[reply]

Is it sun dog or sundog? The title uses one form, the first sentence the other. Should be consistent. If both forms are correct, the first sentence should give both, with the first form matching the article's title: e.g. " A sun dog (or sundog) is a relatively common...." — Franey 12:46, 24 August 2005 (UTC)[reply]

m-w.com gives 'sun dog', AHD gives 'sundog'; 'sundog' outnumbers 'sun dog' on Google. There is probably no standard form, so both could be "correct" (really though, "correct" is POV applied to English spelling: there are no regulating bodies, only established usage).

Ideally the same form would be used throughout the article—and it is, apparently; unfortunately it is not the form used in the title. —Muke Tever talk (la.wiktionary) 01:29, 25 August 2005 (UTC)[reply]

I would consider the American Meteorological Society's Glossary of Meteorology to be the most authoritative reference; it uses "sundog", as do most meteorologists I know. If I knew how, I'd change the page title and have the alternate spelling redirect. --- Gpetty 19:19, 8 September 2007 (UTC)[reply]

Does anyone know how widely the word "sun dog" is used, less or more so than parhelion? I've not heard of either term, so I don't know if it's common in Britain, but it does sound like an Americanism. Any ideas on this, and also where & why the term originated? --User talk:El Pollo Diablo|Talk 01:38, 26 November 2005 (UTC)[reply]

I say "sun dog" and I'm British. Parhelion is more technical. William M. Connolley 21:10, 6 December 2005 (UTC)[reply]

The term (sundog) is used in Canada. Hu Gadarn

'Sundog' doesn't quite capture the beauty of what's happening, I wish there was a nicer name for it. So I use parhelion —Preceding unsigned comment added by Drumnbach (talk • contribs)

I've added what I think is a beautiful picture of this phenomenon. I took it last year outside of New Ulm, MN. Axda0002 14:55, 16 May 2006 (UTC)[reply]

• It's a wonderful photo. Thanks for uploading it. Seventypercent 04:19, 28 January 2007 (UTC)[reply]

Anyone know why it's called a sun "dog" ? 68.39.174.238 04:55, 15 December 2006 (UTC)[reply]

<proposal>The extra suns are "dogging" on the real one?</proposal>

/ Mats Halldin (talk) 11:09, 28 January 2007 (UTC)[reply]

I liked this article but felt it needed a better disposition, so I rearranged things quite a bit. Let me know what you think and, if I messed anything up, don't hesitate to revert it.
/ Mats Halldin (talk) 11:01, 28 January 2007 (UTC)[reply]

• http://englishrussia.com/?p=712

--70.126.236.103 10:31, 25 February 2007 (UTC)[reply]

Cool! Thank you for the link, I've added it to the article.

/ Mats Halldin (talk) 16:18, 25 February 2007 (UTC)[reply]

Didn't Edward IV actually see a Parhelion at Mortimer's Cross? I believe there are actually documented sources. The War of the Roses by Alison Weir mentions it, but I don't know it's source.67.85.254.111 23:06, 4 July 2007 (UTC)[reply]

This article repeatedly uses 'e.g.' when 'i.e.' would be more correct (in that they are clarifications rather than examples). Does anyone object to changing this? 212.84.102.228 18:01, 19 October 2007 (UTC)[reply]

How often do sun dogs occur? —Preceding unsigned comment added by 76.245.122.120 (talk) 02:00, 9 August 2008 (UTC)[reply]

I do not believe they happen very often, but they do occur more commonly than moondogs. Saturday, January 30th 2009. 8:32 AM EST —Preceding unsigned comment added by 49ersfanforlife (talk • contribs) 13:31, 30 January 2010 (UTC)[reply]

Tidied the technical section, removing several erroneous statements. Clarified their appearance, where they can be seen and how often. --Halos25 (talk) 16:11, 18 July 2009 (UTC)[reply]

I think we should delete this section. Perhaps the woodcut itself has cultural significance, but it belongs elsewhere. The first source cited in this section comes from a site about paranormal activity (at the bottom it says "Return to UFO Home" with an alien picture above it), and the second is in German. I can`t verify that this artwork really is a depiction of sundogs and halos, and I`m convinced that this is likely speculation. SweetNightmares (talk) 17:15, 19 August 2010 (UTC)[reply]

I support this view, it clearly doesn't relate to the phenomenon covered by the article. I will move it to the UFO article. --79.168.10.241 (talk) 20:16, 8 November 2010 (UTC)[reply]

The UFO page is protected, so I restored the section even if it doesn't fit I share your view that it has significance enough not to be simply removed. --79.168.10.241 (talk) 20:20, 8 November 2010 (UTC)[reply]