Talk:Solar rotation

Current Carrington Rotation

I've added an automatically updating number for the Carrington Rotation. This is based on the equation given in Meenus and used by sunpy. This estimated rotation may be off by about .16 days. If the current rotation doesn't match the list of start/stop times, please let me know and I will take a look. Blablabliam (talk) 20:22, 13 June 2023 (UTC)

The formula at the top of this article

Someone should check the formula. Maybe a sign is wrong? It implies that rotation is faster, not slower, at the poles! Axel 20:56, 28 October 2007 (UTC)

Ah, sorry, there is a - sign in the definition of B under the formula. My aging eyesight missed it. Maybe it would be friendlier to aging eyes if the definitions were absolute and the minus sign was in the formula? Axel 21:15, 28 October 2007 (UTC)

Is there a reference for this formula? Or does it have a name so I can search for it in published papers? CTC (talk) 13:19, 20 February 2009 (UTC)

Need simpler opener

I think the current setup of this article needs a better lead such as an intro section. As it is, the first sentnence dives into arcane details about how much the rotation rate varies with solar latitude. The intro above the TOC ought to set up what question the article intends to answer, such as: The sun rotates on an axis through its center that is inclined slightly from perpendicular to the [plane of the ecliptic]. Because it is gaseous, the rotation rate is not constant across the whole surface.Birdbrainscan (talk) 08:19, 29 October 2010 (UTC)

Yes. Also, the "slight" offset from the ecliptic is more like 7 degrees, I believe, so totally worth mentioning, including later in the article, that this presents a challenge to the nebular hypothesis, since the Sun should be spinning with the ecliptic, AND with 98% or so of the system's angular momentum, whereas the planets have that large amount, and the sun only has 2% or so of the angular momentum, another challenge to the nh. Bob Enyart, Denver KGOV radio host (talk) 23:04, 2 August 2017 (UTC)

But Why does the rotation rate vary with latitude ?

The article does not give any theories or fluid dynamic explanations of why the rotation rate varies with latitude. Such an explanation could be referenced by the gas giants as well. Cantorman (talk) 17:42, 13 August 2011 (PDT)

The current opening sentence isn't great either. "Solar rotation varies with latitude because the Sun is composed of a gaseous plasma." is not obviously true: single component plasmas in Penning traps are very well approximated as rigid rotors 137.138.11.229 (talk) 15:24, 6 November 2016 (UTC)

• Yes - Need explanation or theories. Heliospheric current sheet says "The Parker spiral may be responsible for the differential solar rotation, in which the Sun's poles rotate more slowly (about a 35-day rotation period) than the equator (about a 27-day rotation period). The solar wind is guided by the Sun's magnetic field and hence largely emanates from the polar regions of the Sun; the induced spiral shape of the field causes a drag torque on the poles due to the magnetic tension force." but it says "may be". Is it due to the magnetic field, or internal fluid motions eg convection (irrespective of magnetic effects) ? - Rod57 (talk) 17:33, 2 November 2017 (UTC)

... Differential rotation says "Differential rotation is caused by convection in stars which is a movement of mass, due to steep temperature gradients from the core outwards. This mass carries a portion of the star’s angular momentum, thus redistributing the angular velocity, possibly even far enough out for the star to lose angular velocity in stellar winds. Differential rotation thus depends on temperature differences in adjacent regions." Sadly no inline cites. - Rod57 (talk) 17:47, 2 November 2017 (UTC)

Orientation

What is the orientation of the solar angular momentum relative to that of the planets? --Rainald62 (talk) 17:54, 28 December 2012 (UTC)

Merge Bartels' Rotation Number and Carrington rotation into this article (proposal)

I am proposing that Bartel's Rotation Number and Carrington rotation be merged into this article, as they are barely notable by themselves and would do better in this article. Primefac (talk) 17:45, 5 September 2014 (UTC)

• Support: This article is quite short still, and could use more material. With low article quality ratings and priorities already, it doesn't make sense to divide the subject three ways. Much better to have a single article of higher quality. Evensteven (talk) 18:07, 5 September 2014 (UTC)

 First one, done ought to do the second also Jim.henderson (talk) 15:28, 30 November 2014 (UTC)

 Done weeks ago

Better to merge something of both into the other

That's all.--Ivan T. (talk) 00:26, 29 November 2014 (UTC)

Larger Picture

This article could also decribe how the solar rotation is related to the travel of Sun around Milky Way center. For example: one line is from center of galaxy to the center of Sun, second line is the axis of Sun's rotation. What is angle between these two lines? — Preceding unsigned comment added by Mlok2008 (talk • contribs) 05:27, 6 January 2015 (UTC)

Solar apex is about 30 degrees north of the Ecliptic which is within a few degrees of the solar equator. I don't see how it's relevant here. Jim.henderson (talk) 16:12, 7 January 2015 (UTC)

My error; Solar apex is about 30 degrees from elliptic pole, thus 60 from equator. Jim.henderson (talk) 17:11, 7 January 2015 (UTC)

Better videos

There are two videos on the page. Both are not the best in showing solar rotation. Couldn't there be one, which is a full rotation of the sun, without any moon or other confusing matter? Also, an example video would be better in white-light or similar, rather than an obscure false-colour image of something in the far UV or IR. — Preceding unsigned comment added by 193.90.243.186 (talk) 21:40, 5 June 2017 (UTC)

The actual numbers given in the first paragraph are inconsistent with the graph shown nearby

The graph clearly shows the rotation period near the Sun's poles to be 34 days, not "almost 38 days". Also, the graph implies the average rotation period is closer to 29 days, not 28.

However, a good reference to cite is Thompson et al. (2003), Ann. Rev. Astron. Astrophys., 41, 599-643. They write that the Sun's surface rotation goes from ~ 25 days at the equator to ~ 36 days at the poles. So maybe the graph is problematic, too?

66.24.161.152 (talk) 17:57, 21 December 2023 (UTC)

Hi. Thanks for pointing this out. Per the source you mention as well as those already referenced in the article, surface-rotation rates depend on what features are being tracked. The inconsistencies you mention appear to be due to editors referencing values derived with different methods. I hope to address this issue soon, but I have added Template:Confusing for now. CoronalMassAffection (talk) 22:58, 22 December 2023 (UTC)

As an amateur, can I put in a plea for clarity and rigour when it comes to explanations and references on this topic, please? Hunting around in book and internet sources yields a ridiculously wide variety of figures for solar rotation rates, whether synodic or sidereal. They seldom explain whether the rates given have been derived from sunspots or other tracers and they almost never cite sources. I am finding the whole thing hopelessly confusing. According to Norton's Star Atlas, the mean Carrington rotation rate corresponds to the mean synodic rotation period at lat = 17°. But one apparently authoritative internet source suggests that figure should actually be 26° (although the accompanying graph seems to suggest around 22° and the formula for calcuating the rotation rate for a given latitude gives yet another result!). Bluntly, if an amateur like me is finding the situation so muddled, it doesn't say a great deal for the ability of professionals to explain the situation with clarity and precision. Surely it can't be that difficult to draft a self-consistent article? If the position is that nobody really knows, then why not say so? But providing contradictory and muddled explanations with inconsistent illustrations and formulae just frustrates those, like me, who are most likely to refer to a Wikipedia article. I'm sorry to be so blunt, but before launching into more arcane aspects like the implications for the nebular hypothesis, might it be an idea to get the basics right..? 92.9.70.178 (talk) 16:08, 9 June 2024 (UTC)