Talk:Milky Way

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This article was nominated for deletion on September 13th, 2006. The result of the discussion was speedy keep.

Archives /Archive

Contents 1 Barred Spiral 2 Inconsistent: number of stars in Milky Way 3 References 4 The sun is in the galaxy's bar? 5 Good Article! 6 UPDATE: Number of stars vandalized 7 Galaxy Infobox? 8 The human experience 9 Perigalacticon 10 Needs more info on the size, shape and structure of the Galaxy 11 Milky Way Structures 12 Four new satellite galaxies 13 Proposed move 13.1 Survey 13.2 Discussion 14 GA Re-Review and In-line citations 15 Intro Paragraph 16 Motion through CMB 17 Nearby dwarf galaxies have surprising composition 18 Gap 19 Andromeda-Milky Way collision 20 absolute visual magnitude 21 Infobox 22 Archive 23 Images. 24 Milky Way Hubble classification 25 Citation 26 infobox (reverted)

[edit] Barred Spiral

I thought that the structure of the Milky Way was disputed, as in, no one is sure yet whether it's Sbc or SBb? Has the fact that it is a barred spiral been confirmed recently? bob rulz 02:37, Nov 13, 2004 (UTC) Well, I don't know back in 2004, but now we are sure it is a barred spiral galaxy. I don't know if they are sure of which type it is. --JorisvS 11:52, 27 May 2006 (UTC)

[edit] Inconsistent: number of stars in Milky Way

193.170.250.70: Hello! The approximate number of stars in the Milky Way is given once as about "100 billion stars" (header), and once as "200-400 billion stars" (section "Structure"). Even if stellar statistics is a rather vague business (if not in this case even a mere shot into the dark), shouldn't the number at least be consistent within the article? Or am I getting something work? Otherwise, keep up the good work. Bye, CalRis.

And the 4th paragraph of the article "Star" says 300 billion. Maybe someone should count them.24.64.223.203 02:09, 11 November 2005 (UTC)

It would take a rather long time to try to count all of the stars in the Milky Way. Hardee67 02:12, 19 July 2006 (UTC)

[edit] References

Someone removed all the <ref> tags, and now they are improperly cited. Should they be put back, or should a different format be used? Unfortunately, I don't know how to use the <ref> style... Ardric47 03:54, 7 April 2006 (UTC)

I fixed this. A pair of anonymous users munged the refs. —Joseph/N328KF (Talk) 04:11, 7 April 2006 (UTC)

[edit] The sun is in the galaxy's bar?

I would like to argue that if this sentence is true:

The galaxy's bar is thought to be about 27,000 light years long

Then that means that the sun is in the galactic bar because this sentense states the position of our sun:

The distance from the Sun to the galactic center is estimated at about 26,000 light-years.

So if the sun is 26,000 light years away from the galactic center, that places us in the galactic bar, since the bar is 27,000 light years long. Funnybunny (^talk/_{Counter Vandalism Unit}) 19:33, 21 May 2006 (UTC)

The bar extends only 1/2 it's length on each side of the center point. Dragons flight 21:22, 21 May 2006 (UTC)

Yeah, the bar is a bar, not a disc. So, assuming the dimensions given in this paragraph are correct, our solar system lies ADJACENT to the bar, not necessarily inside it.

[edit] Good Article!

I've been reviewing this article, and have determined that it meets the qualifications for Good Article Status. It is well written, is factual and well cited, broad in coverage, neutral in tone, stable, and well imaged. I made the small change of including the Galaxy infobox, but otherwise haven't been a part of the editing of this article.

Now that it is a Good Article, editors should review the qualifications for Featured Article Status and set their standards high! This could be a Featured Article at some point, if it continues to improve. Phidauex 20:51, 18 June 2006 (UTC)

[edit] UPDATE: Number of stars vandalized

The article says 400 quadrillion stars, which is clearly wrong and has no citation. Older pages I just googled say 100 billion, and newer ones like this: http://www.seds.org/messier/more/mw.html say least 200 billion other stars (more recent estimates have given numbers around 400 billion). I'll change it to 200 billion for now, just for the sake of taking the QUADRILLION out of there. If someone finds a 2006 source, please update!

[edit] Galaxy Infobox?

Milky Way Galaxy

NASA artist's conception of the Milky Way Galaxy, if viewed along its axis.
Observation data: J2000.0 epoch
Constellation:	Sagittarius
Right ascension:	17h 45.6m
Declination:	-28° 56'
Redshift:	0
Distance:	28,000 ly
Type:	SBbc
Apparent dimensions (V):	360°
Apparent magnitude (V):	~5
Notable features:	Location of our Solar System
Other designations
M0, NGC0
See also: Galaxy, List of galaxies

I noticed that the Galaxy infobox was removed from the article. I think it is better to keep it there, but since there is obviously some contention, I thought I'd ask for some more input.

I find myself (and suspect this to be true of many readers) using the Wikipedia science articles to get quick facts, and make quick comparisons. Is Andromeda bigger than the Milky Way? etc. The Infobox format makes that fast and easy. You don't need to go reading around to find the relevant data, rather, it is placed to the side for easy access for readers looking for a quick tidbit.

I don't think that the fact that we are currently inside the Milky Way is a good reason to remove this 'quick access' to relevant information, since it takes up little more space than the image itself. What do you all think? Phidauex 00:01, 25 June 2006 (UTC)

I think It looks good and would enchance the article. Why was it removed? Aeon ^{Insane Ward} 13:34, 14 July 2006 (UTC)

• I didn't remove it, but support its removal. Much of the information it contains is either not applicable (because we're inside the galaxy it refers to) or filled in with data that makes no sense (again, because we're inside the galaxy it refers to). The standard galaxy infobox contains information that's all applicable to other galaxies, which we view from the outside. I don't think a (corrected) infobox that contains two fields with useful information and all the rest with "N/A" is terribly useful. -- moondigger 20:28, 20 July 2006 (UTC)

N/A isn't hard to fill. We're in it, so redshift is zero. Burnham's notes that no section appears brighter than 5th magnitude, the band circles the sky, and M0 and NGC0 are occasionally used in computerized databases. --Sturmde 05:50, 27 August 2006 (UTC)

• Right ascension, Declination, Distance, Apparent magnitude and Constellation don't make sense; Absolute magnitude cannot be determined from inside -- it refers to the brightness of an object as seen from a particular distance outside of that object. Right ascension and declination refer to the location of the core, yet the galaxy (literally) surrounds us, as you point out when you designate Apparent dimensions as 360 degrees. Distance is meaningless, because (again) we're talking about something that surrounds us. It would be equally correct to say the Distance is 0. Apparent magnitude cannot be said to be ~5 because it varies so wildly depending on where you look. And saying our galaxy is in the constellation Sagittarius is like saying North America is in Denver. -- Moondigger 15:35, 28 August 2006 (UTC)

[edit] The human experience

Please consider modifying the section "The Sun's place in the Milky Way" by appending the following phrase to the sentence that begins, "It takes the solar system about 225-250 million years to complete one orbit" ...

and approximately .0004 orbit since the origin of man.

[edit] Perigalacticon

Circeus removed:

We are presently about 1/8 of an orbit before perigalacticon (the sun's closest approach to the center).^{[citation needed]}

This information is correct (or nearly so) and interesting. Some long time ago, I added it based on work I was doing for a non-wiki project, and now I can't find the appropriate reference. I'd like to encourage others to go looking, but we are definitely nearing perigalacticon now. Dragons flight 02:13, 19 July 2006 (UTC)

[edit] Needs more info on the size, shape and structure of the Galaxy

This article is good, but it lacks allot of detailed information about the size, shape and structure of the Milky Way Galaxy.

For instance, it is not stated how large the Central galactic bulge is. What is its radius? And how much does it bulge out from the normal thickness of the galactic disk?

Also, we are given values for size and mass, but what is the Volume of the galaxy? (i.e. in cubic light years).

What is the stellar density of the Galaxy? Meaning how many stars do we find per cubic light year? Is this value different for different parts of the Galaxy? I assume the core is denser than the rest but how dense? What is the distribution of matter in the Galaxy?

I think these are some of the questions that need to be answered if this is to be a comprehensive article.

--Hibernian 02:32, 25 July 2006 (UTC)

One problem with this article listing those details is that there is not exact information to list. Such specfic details are the very ones that are in question and currently being researched.

[edit] Milky Way Structures

The 3 major parts of the Milky Way are the Galactic Bulge region, Arm Structures, and the Halo region. Should there be 3 sections in the Structure section of this page? Just wondering, CarpD 8/28/06 morning...

[edit] Four new satellite galaxies

SDSS has found four new satellites to the Milky Way: Coma Berenices dwarf, Canes Venatici II dwarf, Hercules dwarf, and Leo IV dwarf.[1]--JyriL ^talk 11:29, 28 August 2006 (UTC)

[edit] GA Re-Review and In-line citations

Note: This article has a small number of in-line citations for an article of its size and currently would not pass criteria 2b.
Members of the Wikipedia:WikiProject Good articles are in the process of doing a re-review of current Good Article listings to ensure compliance with the standards of the Good Article Criteria. (Discussion of the changes and re-review can be found here). A significant change to the GA criteria is the mandatory use of some sort of in-line citation (In accordance to WP:CITE) to be used in order for an article to pass the verification and reference criteria. It is recommended that the article's editors take a look at the inclusion of in-line citations as well as how the article stacks up against the rest of the Good Article criteria. GA reviewers will give you at least a week's time from the date of this notice to work on the in-line citations before doing a full re-review and deciding if the article still merits being considered a Good Article or would need to be de-listed. If you have any questions, please don't hesitate to contact us on the Good Article project talk page or you may contact me personally. On behalf of the Good Articles Project, I want to thank you for all the time and effort that you have put into working on this article and improving the overall quality of the Wikipedia project. Agne 01:00, 26 September 2006 (UTC)

[edit] Intro Paragraph

Is it just me or does 'Although the Milky Way is but one of billions of galaxies in the universe, the Galaxy has special significance to humanity as it is the home of the Solar System.' sound like it was written by some sort of alien? Seeing as how most people reading Wikipedia will be humble human beings, is this pompous phrasing really necessary? Auspiciously 17:37, 27 September 2006 (UTC)

[edit] Motion through CMB

I added a paragraph to the section Speed through space explaining the speed through CMB. Maybe this should be explained in the CMB article, but given the presence of that section, I believe it was needed for completeness. Any comments are welcome. Franjesus 16:02, 23 October 2006 (UTC)

[edit] Nearby dwarf galaxies have surprising composition

According to a recent study: "The chemistry we see in the stars in these dwarf galaxies is just not consistent with current cosmological models," said Amina Helmi of the Kapteyn Astronomical Institute...[2]

[edit] Gap

There's a large gap between "Structure" and its paragraph. I tried to fix it but I'm pretty poor at changing coding. Anybody wanna take a go at closing that gap?

(1sttomars 21:18, 19 December 2006 (UTC))

The article has been vandalized

THe article has been vandalized. "IN THE CENTER OF THE GALAXY IS A GIANT FOOTBALL." was included. I have already removed them.

[edit] Andromeda-Milky Way collision

It has been suggested that Andromeda-Milky Way collision be merged into Milky Way.

(also see Wikipedia:Articles for deletion/Andromeda-Milky Way collision where merge ideas were discussed recently) --mikeu 15:12, 20 February 2007 (UTC)

I don't see anything that speaks against that merger, and non of the merge arguments in Wikipedia:Articles for deletion/Andromeda-Milky Way collision was refuted by any counter points. What speaks against it, in your opinion, mikeu? —KNcyu38 (talk • contribs) 16:29, 20 February 2007 (UTC)

Actually, I'm not against a merger. But a number of people have expressed the opinion that it is notable enough to keep, and a few have been working to improve the article. Wikipedia:Merging and moving pages#Proposing a merger states "After proposing the merger, place your reasons on the talk page..." which is all that I was asking for.--mikeu 18:05, 20 February 2007 (UTC)

Alright, then. I don't want to tread on anyone's toes, but I think that while the information in the collision article is notable and well-referenced enough to keep, it could hardly ever be much more than a stub. In my opinion, it would be an excellent addition to the Milky Way article, though, in a seperate paragraph. Again: I'm not trying to destroy other people's work here, I just happen to think that it would make more sense to merge, in this case. —KNcyu38 (talk • contribs) 02:18, 21 February 2007 (UTC)

I agree. My recent work on the stub was aimed at tidying it up ready for addition to this article. I think we should keep a redirect though, in case people go looking for the collision. Chrislintott 07:42, 21 February 2007 (UTC)

• Support: See AfD discussion. There are not enough reputable sources (i.e., none) for the collision subject to have its own topic. While I support the merger, I would also support deleting this material. Those in favor of keeping the article did not demonstrate that there was a single peer-reviewed scientific article written about this subject. Lunokhod 11:21, 21 February 2007 (UTC)

This is a tricky case; there are plenty of peer-reviewed articles about simulations of the collisions of large galaxies. There are also peer reviewed articles which contain the information about the velocities of the Milky Way and Andromeda. Has anyone published a peer reviewed study of specifically this collision? No, because it would add nothing to the literature. Does it add something to the interest and understanding of the public to use this as an example - yes, it does, and that's why there are a host of popular science articles (in journals of good repute like New Scientist and Sky and Telescope), animations and so on about it. Chrislintott 11:46, 21 February 2007 (UTC)

There are also references [3] [4] that suggest that the motion of M31 is not known with enough certaintity to extrapolate the future motion. This topic seems to be more specultation than a prediction (as the current article states.) I also found this reference [5] which cites Dubinski [6] (where he states that he is presenting a "possible merging scenario".) --mikeu 16:08, 21 February 2007 (UTC)

The first two links above should have been [7] and [8]. --mikeu 22:58, 1 March 2007 (UTC)

• Support: It's been a week and no new information has been added to the article to address the concerns stated above.--mikeu 15:18, 1 March 2007 (UTC)

• Object — The topic has received sufficient discussion in the press to deserve at least a decent article. It is not specific to just the Milky Way or to the Andromeda Galaxy, so I think it should be kept separate and used summary-style. — RJH (talk) 15:50, 5 March 2007 (UTC)

[edit] absolute visual magnitude

Here is a citation [9] that gives -20.9 for the absolute visual magnitude of the milky way. Given the uncertainty in estimating this, I'm sure that there are other references that would give a slightly different value. Absolute magnitude gives -20.5 but does not cite the source.--mikeu 16:23, 21 February 2007 (UTC)

[edit] Infobox

Shouldn't the infobox used in the Andromeda Galaxy article be used in this one too? - 69.19.14.31 22:05, 22 February 2007 (UTC)

At least half the categories don't make any sense when applied to the Milky Way. Chrislintott 22:26, 22 February 2007 (UTC)

[edit] Archive

Someone should consider making archives of past discussions. - 69.19.14.31 22:05, 22 February 2007 (UTC)

Is is now set for Werdnabot to archive comments older than 1 year. The first archive pass will run within a day.--mikeu 01:19, 23 February 2007 (UTC)

[edit] Images.

I fixed the clutter piled up images were making here. Zazaban 03:39, 25 February 2007 (UTC)

[edit] Milky Way Hubble classification

I'm skeptical about that Hubble classification of SBbc for the Milky Way. Neither of the citations given for that sentence actually confirm the classification. Various sources cite different classifications.

• Galaxy morphological classification gives SBb.
• SEDS gives "Sb or Sc"; more recently SB or SAB.
• SAO gives Sb or Sc (Sbc).
• Astronomy Adventures gives SBc
• Rolf A. Jansen at ASU gives Sb or Sc, and barred.
• University of Maryland gives Sbc or SBbc.

&c.

The SBbc appears to be somewhat speculative, merging earlier classifications with the barred-spiral classification. So if there is an accurate 2005 classification for the Milky Way, does somebody have a good source? Thank you. — RJH (talk) 18:34, 4 March 2007 (UTC)

I moved the two references from the classification down to the sentence about the Milky Way mass, where they are more relevant. — RJH (talk) 15:47, 5 March 2007 (UTC)

A portion of the text has been rewritten to try and satisfy this. — RJH (talk) 17:18, 14 March 2007 (UTC)

[edit] Citation

The Milky Way's absolute magnitude, which cannot be measured directly, is assumed by astronomical convention to be −20.5, although other authors give an absolute magnitude of -21.3.

Shouldn't there be a reference here? Hornberry 23:52, 14 March 2007 (UTC)

I've been looking for info on this. I could not find a source that detailed how the magnitude was estimated. Here's a note that I posted above. "Here is a citation [10] that gives -20.9 for the absolute visual magnitude of the milky way. Given the uncertainty in estimating this, I'm sure that there are other references that would give a slightly different value. Absolute magnitude gives -20.5 but does not cite the source.--mikeu 16:23, 21 February 2007 (UTC)" There are two places where the magnitude is given in this article. The Absolute magnitude article also gives a value for the milky way.--mikeu 00:12, 15 March 2007 (UTC)

Let's add the aa.springer reference for now and when other references pop up we can start redebating. Hornberry 02:55, 15 March 2007 (UTC)

[edit] infobox (reverted)

I reverted the addition of an infobox [11] See comments above. Most of the info was not applicable (coordinates, constellation), confusing (distance) or just wrong (Messier never labeled it M0) --mikeu 03:44, 20 March 2007 (UTC)