Talk:Sun

Template:WP1.0

Peace

We are all children of the sun, we all came out of the sun so why do we fight? We all came from one source. —Preceding unsigned comment added by 79.72.91.250 (talk) 21:47, 8 October 2008 (UTC)

Life Cycle Image

I believe the image of the suns life cycle is slightly incorrect because the "Now" arrow is more towards 4.5 billion years old, while the earth is about 4.4 billion years old, the sun is more towards 5 billion years old. Gemroth (talk) 00:09, 18 March 2008 (UTC)

Adding to that,

Hotly debated theory cited as fact.

'In fact, even during its life in the main sequence the Sun is gradually becoming more luminous, its surface temperature slowly rising. The increase in solar temperatures is such that in about 900 million years, the surface of the Earth will become too hot for the survival of life as we know it.[31] After another billion years the surface water will have completely disappeared.[32]'

Anon 03:57, 24 April 2008 (GMT)

Age of Sun, of Galaxy and of Universe

It seems disproportionate to assume the ages of either the Milky Way galaxy, other galaxies, and the universe should all be so close to the estimated age of the Sun when evidence in the form of short-lived isotopes such as lithium, which are consumed with great rapidity, are found abundantly in stellar spectra of hot blue stars forming in the 'stellar nurseries'. Moreover, many stars are found in the Hertzsprung-Russel diagram which are much older than the Sun.

It is more likely the Sun's entire existence is not in the center of the time of existence of the Galaxy and certainly not in that of the entire universe. To put it more carefully, the Sun's existence is not in the center of space-time.

SyntheticET (talk) 16:43, 20 October 2008 (UTC)

Updates / Alterations

I think the description in the first section of this article about the "surface spectral composition" of the Sun is misleading as it implies that the Sun has a solid surface which is factually incorrect. It would be more appropriate to say the spectral composition of the photosphere is ... and then provide a link to the photosphere section of the article.

Secondly recent research has actually re-established the possibility of the Earth being swallowed up during the Sun's red giant phase, and this should be included. reference for this:

Monthly Notices of the Royal Astronomical Society (DOI: 10.1111/j.1365-2966.2008.13022.x)

Thanks,

Gaz —Preceding unsigned comment added by 144.124.16.28 (talk) 13:25, 27 February 2008 (UTC)

The discussion of plasma in the structure section comes out of nowhere. I would fix it but the article is semi-protected. —Preceding unsigned comment added by 68.13.192.233 (talk) 03:51, 8 October 2008 (UTC)

Life Cycle

The "Life Cycle" section contains :-

"Each second, more than 4 million tonnes of matter are converted into energy within the Sun's core, ...". That is true : but it seems to me capable of being misunderstood, by those of inadequate sagacity, as meaning that about 4 million tonnes of hydrogen are consumed per second. See, for example, http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2008/03/01/nsky01.xml paragraph 4.

In the "Core" section, we see "About 3.4 × 10³⁸ protons (hydrogen nuclei) are converted into helium nuclei every second"; but the ordinary reader will not rapidly perceive that, since the AMU is 1.66 × 10⁻²⁷ kg, the mass of hydrogen uses is about 565 million tonnes per second.

I suggest that the second paragraph of "Life Cycle" be rephrased to include both the 4 million and the 565 million, for clarity. But check the exact numbers.

The page does not appear to be editable by me.

82.163.24.100 (talk) 10:29, 3 March 2008 (UTC)

The page is not editable by you, because it is semi-protected. I suggest getting an account, which will allow you to edit semi-protected articles such as this one.

What you say does make sense to me, but I'm not sure about the 585 figure - I cannot find a source to confirm that. [1] says that it's actually 685 million. I think that an off the cuff calculation like that would be considered "original research", and be quickly edited out of the article if there is not a scholarly source added to confirm it. MichelleG (talk) 13:24, 4 March 2008 (UTC).

Surface Area

Is wrong. That is the value for km^2, not m^2, it should be roughly 6x10^18 m^2. I checked the reference, and its wrong there too, but just do the maths on the diameter. SA = 4*pi*(r^2)

Cheers,

Taffy —Preceding unsigned comment added by 62.31.163.74 (talk) 22:22, 6 March 2008 (UTC)

I was just going to say the same thing, except the given value is correct in units of m*km, not km^2 = 10^6 m^2 ( which is a clue to the cause of the error. )

It got my attention because of the "citation needed" notation on the mass conversion rate. This value is just a restatement of the luminosity in units of kg/sec = watts/c^2, to the one significant figure given. It reflects a presumption of equilibrium between the luminosity and the total solar power.

I noticed that the given luminosity is pi*1000 times the given solar area * given mean intensity, instead of the required factor of pi. I was surprised to notice that the discrepancy was in the given area.

68.77.25.250 (talk) 03:27, 22 March 2008 (UTC)

does sol=Sun?

Please could I have some help?

A website was giving information about 'sol'. Does that mean the sun?

from KT.Woot

KT.Woot (talk) 19:31, 17 March 2008 (UTC)

Sol is a name for the Sun. Not commonly used, though, in science or out. Saros136 (talk) 19:52, 17 March 2008 (UTC)

From the Latin, no? Certasinly its the Spanish/Portuguese word for the Sun. Thanks, SqueakBox 01:11, 20 March 2008 (UTC)

It is the Latin name for the sun yes and as such is also where the adjective Solar (system) comes from, and like Luna (ad. Lunar) for the moon is the main equivalent to the english names. Terrasidius (talk) 14:36, 31 March 2008 (UTC)

Volume

The unit of the volume seems to be wrong. From the source cited (NASA) we can see that the actual volume is 1.412 x 10^18 km^3, that is 1.412 x 10^27 m^3 and not 10^21. 99.241.94.222 (talk) 13:59, 30 March 2008 (UTC)

Indeed. I made the correction (at Template:Solar System Infobox/Sun). ASHill (talk) 20:49, 30 March 2008 (UTC)

Location section

I have created a new section titled "Location within the galaxy," since I was disappointed to find that this info was not currently in the article. For now, I have simply copied the wording from the "Sun's Location" section of the Milky Way article. This subject matter is a little out of my field, though I'm sure more qualified editors will add and make changes to it. --Jleon (talk) 04:06, 14 April 2008 (UTC)

Contradictions

there seem to be lots of contradictions in this piece e.g.

overview “This is suggested by a high abundance of heavy elements such as gold and uranium in the solar system. ……..

No mention of these in the Photospheric composition listed in adjacent table. Presumably this is because here you are referring to the whole solar system and not just the Sun. In that case it would be helpful to explain why the planets have the heavy metals but the sun does not if they are all derived from the same source.

Similarly further down in Chemical composition Element abundances According to Bahcal (1990)[42] cited in Thoul (1993:15),[43] the characteristic mass fractions of some elements are: Hydrogen: 34% Helium: 64% Oxygen: 1% I.e. 99% are the above . So where are the heavy metals?

Also

Location within the galaxy The Sun may be found close to the inner rim of the Galaxy's Orion Arm, in ....

To a novice this is a little confusing Perhaps: The Sun is one of many stars in the Galaxy called the Milky Way. Within this Galaxy it is found etc etc Cmlawrence (talk) 11:35, 14 April 2008 (UTC)

Re gold and uranium: heavy elements are present only in trace amounts in any star, including the Sun, and aren't among the 10 most abundant elements. However, all heavy elements are more abundant in the Sun than in low metallicity (heavy element abundance) stars. I've (hopefully) clarified that point. ASHill (talk) 22:27, 16 April 2008 (UTC)

the moon is made out of cheese and the sun is made out of tomatoes and hot sauce —Preceding unsigned comment added by 98.240.223.248 (talk) 00:38, 29 April 2008 (UTC)

The Ultimate Fate of the Sun / Solar System

I was thinking that this could be filled this under the Life cycle section, however I feel that this should have its own section.

While many discuss the ultimate fate of the sun as simply the sun turning into a red giant in about 5-6b years and in about 10b years the sun expected to have totally exhausted its fuel, a much larger event looks very likely to occur in about 3 billion years [2] when the Milky Way and the Andromeda Galaxy's pass very close, possible through each other. [3].

This can create many different possibilities. Here are a few.

1- the sun thrown out of the galaxy by gravitational effect into the deep void of the universe

2- the sun thrown out of the galaxy by gravitational effect, however the velocity isn't great enough to have escaped the gravity of the Milky Way's central black hole. This will eventually cause the sun to be pulled back towards the black hole, passing through much hotter, denser gas that surrounds the black hole, and possibly passing very close to the back hole, thrown into the opposite direction into a possible erratic orbit.

3- the sun is thrown out but it is caught by the gravity of Andromeda's black hole.

4- the sun could pass too close to either of the black holes and get caught in the event horizon.

5- when the 2 Galaxies pass each other, major star formation will occur creating many more super massive or hyper massive stars with short lives. The effect of these massive supernova and hypernova explosions could greatly effect the sun in some way.

6- when the two galaxies eventually merge creating a massive super hot elliptical galaxy, two massive black holes will orbit close around each other and possibly merge. Now if the sun was lucky to survive the merger, what effect would these have on the sun?

There are other possibilities, however it is almost certain that the sun will enter a period of severe disruption which possibly could lead to its destruction and I would like this topic to be discussed and eventually be entered into the main article.

This could also be file in under the solar system, as it's future will also be greatly effected by the galactic collision long before the sun turns into a Red Giant. --anon 87.192.200.169 (talk) 15:10, 1 May 2008 (UTC)

None of these—even if they do occur—are actually likely to significantly affect the Sun because we're very unlikely to pass near enough to any system in either galaxy, particularly the center of Andromeda, given the vast size of each galaxy. See Formation and evolution of the Solar System#Galactic evolution for a discussion of the likely effect on the Solar System of the collision between the Milky Way and the Andromeda Galaxy. ASHill (talk) 20:55, 1 May 2008 (UTC)

Age

This article claims Sun's age is about 4-5 billion years. But the earth article claims similar age. Does that mean both celestial objects were born concurrently, independently? It is impossible.Anwar (talk) 20:07, 7 May 2008 (UTC)

Concurrently, but not independently. Formation and evolution of the Solar System. ASHill (talk | contribs) 20:10, 7 May 2008 (UTC)

Sun picture Viewer Mars to Sun (Image 15)

• http://www.welt.de/wissenschaft/article2033800/Nasa_schwaermt_von_perfekter_Phoenix-Mission.html

194.66.226.95 (talk) 09:26, 27 May 2008 (UTC)

The end of life on Earth Contradictions 500 million years? 1 billion years? 1.9 Billion years?

I am a little confused as to what the information on this article and the Earth article says about the end of life on Earth. It says that in 900 million years all plants on Earth will die and in an additional 1 billion years all of the water on Earth will evaporate. Does this mean that in 1.9 billion years the Earth's ocean will evaporate? It is confusing because the sources say in 1 billion years the Earth's oceans will evaporate but the article says a billion years later, meaning after 900 million years the oceans will evaporate. So is it 1 billion years or 1.9 billion years that the Oceans will evaporate. Another thing is that on the Earth article it says also that in only 500 million years all life on Earth will die but this contradicts the place where it says that in 900 million years all plants will die and millions of years later on animals will die. I am so confused by these contradictions. Please help clarify this for me.Maldek (talk) 01:15, 19 June 2008 (UTC)

The 1.9 billion number was made up; it wasn't in any of the sources. However, there is considerable uncertainty in precisely when the Sun will become too hot for water to exist on the Earth's surface (probably the best criterion for the possibility of life); around a billion years is probably the best estimate, and we really shouldn't try to be any more precise than that. I've updated the section to bring it in sync with the relevant main article, formation and evolution of the Solar System. ASHill (talk | contribs) 23:59, 19 June 2008 (UTC)

Images

Sorry to barge in, the images in the article may have been selected on excellent grounds. However, I found Image:STEREO-B_solar_eclipse.jpg and Image:Mass_eject_in_ultraviolet_light.jpg and to my untrained eye they look superior to some of those in the article. Thought you might consider them for inclusion. Dhatfield (talk) 23:21, 19 June 2008 (UTC)

Was bold - made the edits I thought appropriate. Please check wording of captions for accuracy. Dhatfield (talk) 00:07, 20 June 2008 (UTC)

The Sun becomes a Red Giant in 5.43 billion years.

The Sun is 4.57 billion years old, as confirmed in this article. and will spend 10 billion years as a Main Sequence Star before it becomes a Red Giant. Is it okay to change 5-6 billion years to a more accurate 5.43 billion years? Thank You.Maldek (talk) 04:40, 20 June 2008 (UTC)

See my reply in one of the (at least) two other places you made this comment. Short answer: no. ASHill (talk | contribs) 13:37, 20 June 2008 (UTC)

Core figures discrepancy

There is a dual discrepancy in the figures of core radius, density, energy output and specific power figures, per volume and per mass units each. Using the figures from the article rounded to 2 decimals: the solar radius is 7.0×10⁸ m, the core radius is 0.2 total radius, total core power is 3.8×10²⁶ W. This yields the volume of the core of 1.1×10²⁵ m³, and its specific power of 33 W/m³. The article gives 0.3 μW/cm³ (note that 1 μW/cm³ is the same as 1 W/m³), 100 times less. Next, given the average density of the core of 1.5×10⁵ kg/m³, find the average power per kg be 3.8×10²⁶ W / (1.1×10²⁵m³ × 1.5×10⁵ kg/m³)) = 2.3×10⁻⁴ W/kg = 230 μW/kg, while the article cites 6 μW/kg, this time 38 times less.

I am only reporting the discrepancy, as, lacking a reliable source for solar core physical parameters, I am unable to sensibly correct the article at the moment.

— Fregimus (talk) 09:54, 26 June 2008 (UTC)

Luminosity figure discrepancy

To the best of my knowledge, the value for luminosity should be 3.826×10²⁶ watts and not 3.846×10²⁶ watts. There are two different arguments supporting my view.

First: The text cites a mass conversion rate of 4.26 million tons per second which is equivalent to 4.26×10⁹ kg/s. Multiplying this by 2.99792458×10⁸ m/s squared the result is 3.828697×10²⁶ W.

Second: If the lumen output, given as 3.75×10²⁸ lm, is divided by the luminous efficacy of 98 lm/W, a value of 3.82653×10²⁶ W is obtained.

Therefore, I consider the listed value of 3.846×10²⁶ watts for the luminosity to be in error. I truly hope the staff in charge of this outstanding article performs some checking and decides whether if the changes apply.

— Burst3 (talk) 18:36, 07 July 2008 (UTC)

The current value looks to be accepted. For example, this paper (DOI:10.1086/321493: section 2.1) reports that the current best estimate is 3.842, with estimates disagreeing at the 0.2% level. The 3.846 value currently used in Sun is cited, so it shouldn't be changed without reliable sources that contradict the reliable sources arguing for 3.84. (However, I could see chopping one sig fig off, so we only report 3.84 10²⁶ W.) ASHill (talk | contribs) 19:31, 7 July 2008 (UTC)

Comparison of how big the sun appears when seen from the surface of different planets.

I created an image named "Comparison_sun_seen_from_planets.svg‎" (http://upload.wikimedia.org/wikipedia/commons/d/df/Comparison_sun_seen_from_planets.svg). The headline already says what it shows. The image is uploaded to CC and can be added if found useful. The German version of this article is unprotected so you can watch it "in action". :) I used the lens equation with an arbitrary value for the distance eye-lens <-> retina, then normalized the results. Nevermore4ever (talk) 17:16, 18 July 2008 (UTC)

Solar Cycle references

The article states: "Solar activity minima tend to be correlated with colder temperatures, and longer than average solar cycles tend to be correlated with hotter temperatures."

I'd like to see a reference for this info. —Preceding unsigned comment added by Kdconod (talk • contribs) 21:02, 24 July 2008 (UTC)

Chemical composition

This section is almost impossible to read and makes little sense to the layman. Could somebody please write it in more accessible language? AJKGORDON«» 13:54, 28 July 2008 (UTC)

Yeah, that's bad. I'll try to work on it. (Finding references for Solar abundances is actually annoyingly tricky, so it may take me a bit of time to clean it up.) —Alex (ASHill | talk | contribs) 14:11, 28 July 2008 (UTC)

Thank you. AJKGORDON«» 18:11, 28 July 2008 (UTC)

I've rewritten the section (diff). The new version is much shorter. Much of the material in there was probably not worth saving at all, but some discussion of diffusion is perhaps warranted, although a separate article (something like Chemical composition of the Sun) is probably a better place for that level of detail. —Alex (ASHill | talk | contribs) 01:52, 30 July 2008 (UTC)

I disagree. The material in there needed to be saved. I'll give a try at a rewrite. Headbomb {ταλκ – WP Physics: PotW} 02:37, 30 July 2008 (UTC)

Well it seems I can't make much sense of the source material. I've kept things reverted as someone else may succeed where I've failed. Feel free to return to Alex Ashill's version. Headbomb {ταλκ – WP Physics: PotW} 03:04, 30 July 2008 (UTC)

My intent was not to necessarily permanently remove all the topics, but the chemical composition section as it was was essentially unreadable and useful as little more than a collection of largely-outdated references. I tried to write a coherent, readable summary. I would be happy to see the topics that sort-of-existed before discussed in a readable manner as well, but the subsections all need to be rewritten essentially from scratch (which is why I deleted them all). In the meantime, I'll revert to my version.

The sources cited are quite technical; a good review article is probably a better place to go. —Alex (ASHill | talk | contribs) 03:14, 30 July 2008 (UTC)

The article of Lodders et al. 2003 (and some references therein) (see ref 59 in Uranus) should be cited instead of old papers from the 70-th. Ruslik (talk) 07:00, 30 July 2008 (UTC)

The section abut the composition of the sun is flawed: "The most abundant metals are oxygen (roughly 1% of the Sun's mass), carbon (0.3%), neon (0.2%), and iron (0.2%).[45]" —Preceding unsigned comment added by 195.222.17.101 (talk) 20:00, 22 September 2008 (UTC)

Why? I don't know if the numbers are quite right, but I suspect you are confused about the use of the word "metal". For astronomers, everything heavier than Helium is a metal, thus the sentence is technically ok. See Metallicity. It might be better to formulate this in a way more friendly to lay readers, though. --Stephan Schulz (talk) 20:12, 22 September 2008 (UTC)

Give that the immediately preceding sentences are "The Sun is composed primarily of the chemical elements hydrogen and helium[....] All heavier elements, called metals in astronomy, account for less than 2 percent of the mass", I think this is adequately explained. The use of the term "metals" in astronomy is confusing, but I think it really does simplify and clarify the discussion of chemical composition. I'm very open to suggestions for clarifying that section, of course. —Alex (ASHill | talk | contribs) 20:28, 22 September 2008 (UTC)

Didn't know that, thanks for the clarification. Maybe you can add a link to the metallicity article? Thanks. —Preceding unsigned comment added by 195.222.17.101 (talk) 10:22, 24 September 2008 (UTC)

The word "metals" is a link to the metallicity article. —Alex (ASHill | talk | contribs) 13:21, 24 September 2008 (UTC)

Disputed - Color of the Sun

The uncited comment about the color of the Sun appearing yellow because the blue light is scattered in the sky (also explaining why the sky is blue) seems to be, at best, in dispute. I could not find a definitive reference in support of this, and my search found at least one dissenting opinion (the book "Bad Astronomy" by Philip C. Plait, 2002) which claims that the amount of blue light that is scattered is not enough to account for the perceived color shift. Is there a definitive reference that shows that the reason given here is correct? If not, I'd recommend rewriting or removing that claim. 71.164.160.112 (talk) 22:39, 19 August 2008 (UTC)

I found a reference that supports the claim and have added it to the article thanks for pointing it out! Skeletor 0 (talk) 17:30, 9 September 2008 (UTC)

Regrettably, there is a great deal of quite diversely incorrect information on the web, and in introductory astronomy text books, about the Sun's color. The Sun is only yellow in two respects. It is "yellow" relative to the blue spectroscopy reference star Vega. And it variously appears yellow or red or orange when viewed low in the sky. The Sun itself is a simple 5800K blackbody, whose light has a chromaticity of white. Just white. White outside the atmosphere. White on the ground when not low in the sky. Inherently white, not white because it is bright. Nor because of chromatic adaptation (D58 is between the blue sky D65 and redish incandescent D50 white points). Just white. All else is creative bogosity. Apparently generated in attempts to reconcile whiteness with misunderstood stellar classification, preexisting bogosity, or preconceptions of yellowness. Which the article currently propagates. As the earlier user points out, the article is currently incorrect. And the yellow Image:Sun920607.jpg is misleading. I'd add a disputed tag, but the article is not anonymously writable. Example cite: [4] (as is standard for the web, the page uses bluish D65, so the Sun's white color is represented as pinkish, and a D65 calibrated monitor will emit white light for it). Fyi. 98.216.110.149 (talk) 06:16, 29 October 2008 (UTC)

Should it be 'The Sun'

A minor point, perhaps, but whenever we refer to this body, we always say 'The Sun', not 'Sun'. Note the heading above the image at the top of the page. I know there is an article called 'The Sun', for the UK newspaper. But that could become 'The Sun (newspaper)'.

Similarly with 'The Moon' - but unlike 'Earth' (although we sometimes say 'The Earth' but it doesn't sound right) and Mercury etc. The article does redirect when using the search term 'The Sun', but I think the article should be 'The Sun' and users should be redirected to it if they put in 'Sun'. —Preceding unsigned comment added by Jackins (talk • contribs) 10:41, 19 September 2008 (UTC)

No. See WP:MOS#Article_titles and WP:NAME. Articles are avoided unless part of a proper noun. Also, while my "we" may be different then your "we", we do not always use the name with the article, e.g. in "Our sun is a normal yellow dwarf". --Stephan Schulz (talk) 11:13, 19 September 2008 (UTC)

i cant edit

...but i think Sunlight should go in the 'see also' section, (cos' it's relevant to those still here on this planet) . 79.76.146.25 (talk) 03:19, 24 September 2008 (UTC)

I added a wikilink to sunlight in the introduction to the article. The normal policy on Wikipedia is to avoid adding links to the 'see also' section that are included in the main text. Thanks for the suggestion, and please do create an account and make any edits you feel appropriate! (Normally, anyone can edit Wikipedia articles, but this article gets so much traffic and vandalism that editing without an account is disabled.) —Alex (ASHill | talk | contribs) 13:21, 24 September 2008 (UTC)

Song Of The Sun

Bob Thomas and Huw Pudner have written "Song For The Sun" in a folk style ballad. Probably inspired by the heavy and persistent rain that fell in August 2008 and with inspiration from" The Worm Forgives The Plough" by John Stewart Collis. —Preceding unsigned comment added by 82.11.213.153 (talk) 15:22, 29 September 2008 (UTC)

Candle releases more energy than the Sun ?!

The article says:

This actually corresponds to a surprisingly low rate of energy production in the Sun's core—about 0.3 W/m³ (watts per cubic meter). This is less power than generated by a candle.

Obviously should be "less power per volume than that generated by a candle". And it's not low rate of energy production but low power to volume ratio. And the (watts per cubic meter) parenthesis comment is silly - if anyone knows what watts per cubic meter means then he would surely know what W/m³ means also.

Extent of hydrogen/helium ionization

I'm in astro 320 at U of Alberta (MT tomorrow :)) and I am confused about the reason why hydrogen is ~100% ionized in Sun's core (T = 1.57*10^7 K; ref. my assignment). To calculate N(II)/N(total), I calculated N(II)/N(I) using the Saha eqn (using electron density = 6.1*10^31 m^-3), and found N(II)/N(total) by noting that: N(total) = N(I) + N(II). Also, I used partition functions, Z(H(I))=2 and Z(H(II)) = 1 (no degeneracy for proton). Anyway, I calculated that N(II)/N(total) = 0.709, or 70.9%. This calculation neglected helium (all hydrogen in sun), but helium would lower hydrogen ionization energy by compressing H's orbitals (is this right? or would it raise the I.E.?) from 13.6 eV, which (I think) would, if lowered, increase the calculated fraction. Conversely, He is also ionized (III or II) producing more `free` electrons to reduce the fraction of ionized Hydrogen. Are there other effects to account for the 100% ionization. —Preceding unsigned comment added by Bizarrini (talk • contribs) 01:20, 15 October 2008 (UTC)

If one were to observe it from Alpha Centauri, the closest star system, the Sun would appear to be in the constellation Cassiopeia.

This sentence, the final line of the section "Solar Space Missions", seems irrelevant to me. The position of the Sun viewed from another star system says nothing at all about the nature of the Sun, and its not a particularly interesting piece of trivia. Perhaps in should be included in the article about Alpha Centauri, but its inappropriate here, in my opinion. FiatLux23 (talk) 08:53, 22 October 2008 (UTC)

Agreed. I think the statement is too specifc to be valid on the sun page Suntanman (talk) 17:41, 24 October 2008 (UTC)