Talk:Sun

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[edit] 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)

[edit] 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)

[edit] 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).

[edit] 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)

[edit] 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)

[edit] 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)

[edit] 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)

[edit] 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)

[edit] 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)

[edit] 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)

[edit] Sun picture Viewer Mars to Sun (Image 15)

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