Talk:Whirlpool Galaxy

Discrepancies in distance
In the initial blurb about the galaxy it states that it is approximately 31 million LY away, then later says it's distance was derived via supernova to be approximately 23 million LY away. I'm not sure which is the actual correct distance, so I'm just leaving a note here about it. — Preceding unsigned comment added by 71.234.90.100 (talk) 20:50, 2 June 2011 (UTC)
 * It looks like the 23 M Ly is a more recent estimate, which probably should be noted in the article's lead. --George100 (talk) 08:21, 3 June 2011 (UTC)
 * That's correct. I've tried to reconcile this discrepancy in the lede.  Careful With That Axe, Eugene  Hello...  09:12, 3 June 2011 (UTC)

The discrepancy is still there. NASA states 31 million lyr.Paulhummerman (talk) 11:11, 9 September 2021 (UTC)

Look at the Picture
Aside from the extremely fun stuff being discussed here, I think that one point needs to be made extremely clear, and that is; we've found Jesus. —Preceding unsigned comment added by 75.0.187.255 (talk) 04:12, 26 October 2010 (UTC)

Image:M51 Whirpool Galaxy.JPG
An edit by anonymous user 219.76.96.9 lead me to http://antwrp.gsfc.nasa.gov/apod/ap020710.html, the original source of the image. The image is copyrighted, and as I assume that explicit permission has not been obtained to use it, I'm removing it from the page and flagging it as a copyvio. --Ardonik 02:00, Jul 29, 2004 (UTC)


 * I've now obtained permission and re-instated the image. Arcturus 17:56, 10 Sep 2004 (UTC)
 * Outstanding. Thank you!  --Ardonik.talk 23:21, Sep 10, 2004 (UTC)


 * Andromeda Galaxy also had an apparent copyvio image from http://antwrp.gsfc.nasa.gov/apod/ap040718.html. -- Curps 02:39, 29 Jul 2004 (UTC)

Incomplete/useless references
Some of the references on this web page are incomplete. "STSCI (2001)" simply cannot be used to check the validity of the information (a distance measurement). The Salo & Laurikainen reference is missing the volume number, which is needed for journal references. Someone should clean up these references. George J. Bendo 15:19, 20 September 2006 (UTC)


 * Fixed. WilliamKF 18:59, 12 October 2006 (UTC)


 * Thank you WilliamKF. George J. Bendo 19:37, 12 October 2006 (UTC)

Comments on 15 October edts
On 15 October I removed a few rambling statements from the Whirlpool Galaxy article. Whoever had written this article would frequently discuss topics indirectly related or unrelated to M51. This includes a discussion on the large scale structure of the universe which was not appropriate here. I also removed a very poor, very misleading explanation of the interaction-induced spiral arm structure in M51. I may attempt to write a better description once I find a reference. (I may try either the Binney and Tremaine or Binney and Merrifield books for basic descriptions of the process. Papers by Toomre and Toomre may also contain good information.)

I have also revised the description of M51's group membership. Note that four references all indicate that NGC 5194 is not part of the M101 Group. The only places where such an assertion is made is the Ferrarese paper (which seems hesitant in drawing such a conclusion) and the Altas of the Universe website (which has not been reviewed for scientific accuracy like the journal articles cited in the M51 entry). If anyone disagrees with my conclusions, please indicate so here. George J. Bendo 00:43, 16 October 2006 (UTC)

Telescope size
You may want to use millimeters (mm) in describing telescope apeture. When converting from apeture in millimeters to apeture in inches, and vice versa, all you would need to do is multiply (in. to mm) or divide (mm to in.) by 25. The use of centimeters can throw one off, especially in the astronomy world, when telescopes under 4 inches are marketed in millimeters and etc. Rwboa22 20:48, 21 March 2007 (UTC)
 * Agreed. I'll change these numbers since it is obvious that no one has raised an objection in the 2 years since Rwboa22 posted their comment.Trilobitealive (talk) 02:05, 14 June 2009 (UTC)

Apperance of Whirlpool in a Telescope
I had the privledge to see the Whirlpool Galaxy (M51) on Tuesday night/Wednesday morning at a dark sky observing site north of Fort Indiantown Gap, Pennsylvania, using a 12-inch Dobsonian telescope. Although the comment in the article states that a 150 mm (6-inch.) telescope will show the spiral structure, that is only true with a refractor telescope, which does not have a central obstructuction (i.e. the secondary mirror). For best results, at least a 250 mm (10 in.) or higher telescope with a good wide-field eyepiece would be better. This dark sky sight, roughly 1,100 feet above sea level, allowed me to see a "hint" of spiral arm in the system, and works better at higher magnifications (100X and higher). Rwboa22 20:54, 21 March 2007 (UTC)


 * While what you saw may be more accurate than the text, you cannot use your own personal observations to write Wikipedia articles. That would be original research, which is avoided in Wikipedia.  Can you supply a reference to support your claim?  (Alternatively, if the Wikipedia article is unreferenced, remove the information from the article.)  Dr. Submillimeter 22:22, 21 March 2007 (UTC)

Dates of Sketch and telescope used: 1845 and/or 1847?
Just wondering: In this article the date below the whirlpool galaxy sketch (showing it to be a spiral) by Lord Rosse says 1845, and it is mentioned that he made the sketch with his 72-inch reflecting telescope, but the article on Lord Rosse says that the 72-inch telescope was not put into use until 1847. So, date-wise that seems rather strange: a sketch "attributed to" the 72-inch telescope seems to predate that telescope by two years.

Telescope date of use can be found at http://en.wikipedia.org/wiki/William_Parsons%2C_3rd_Earl_of_Rosse

Mnentro 13:31, 1 August 2007 (UTC)

Section /Visual appearance - tagged
Please describe and show examples of what you find "inappropriate for WP" in this section. Without this description no other editor can know exactly why you have tagged this section. SmithBlue (talk) 14:15, 14 November 2008 (UTC)
 * I don't know why they tagged it. I rewrote it in the tone I've seen in other articles and deleted the cleanup notice.Trilobitealive (talk) 02:33, 14 June 2009 (UTC)

Factual Error corrected
This article stated that Lord Rosse in 1845 discovered M51, which is impossible since it is a Messier object. Obviously, it was discovered by Messier. I corrected this mistake and included an incomplete reference.

Nick Beeson (talk) 15:03, 9 March 2009 (UTC)

Factual Contradicted Distance correction
The distance to M51 is given as 31 million ly in the introduction and 23 +/-4 Mly in the sidebar. The 23 Mly is referenced to 2006. There is no reference for the 31 Mly number; however, Burnham gives 35 Mly. Given this I'm revising the introduction to use 23 Mly. —Preceding unsigned comment added by DGamey (talk • contribs) 14:51, 9 August 2009 (UTC)


 * How about +- 10 Megaparsecs? Would that be wrong? Then we could get the Whirlpool Galaxy and the Milky Way galaxy within the confines of a 10 by 10 by 10 Megaparsec Cube. Which would be about a billionth of one estimate of the size of the universe. So it's right around the corner on the universe scale.WFPM (talk) 20:19, 31 January 2013 (UTC)


 * Note when you get into distances related to the size of the universe, it's better to think in terms of Megaparsecs, with 1 Megaparsec being 3.26 million light years or 10E^24.5 light years. In that context, the approximately 10 Megaparsec distance to the Whirlpool is only a short distance relative to the estimated size of the universe. Of course the process whereby any estimate was arrived at would,of course, be interesting.WFPM (talk) 05:03, 9 February 2013 (UTC)

Galaxy: Exploring the milky way
Galaxy: Exploring the milky way says the distance from earth is 37 millionLY away and the size is 100K LY. should i put this in? Mocha2007 (talk) 18:00, 3 December 2010 (UTC) Bold text

Whirlpool name
When or who changed name from M51 to Whirlpool galaxy? John a s (talk) 20:48, 24 July 2015 (UTC)
 * The name was never changed from one to the other, but rather the two names are synonyms for the same object. M51 is the catalog designation from the frequently-used Messier catalogue compiled by Charles Messier, while the name "Whirlpool Galaxy" is the common name by which the galaxy is referred to. They are both valid commonly-used names for the object. StringTheory11 (t • c) 03:39, 25 July 2015 (UTC)
 * Thanks. I was just wondering when the name Whirlpool galaxy was first used. John a s (talk) 07:32, 8 August 2015 (UTC)

New distance determination
A new precision determination of M51's distance gives it as 8.58 +- 0.1 Mpc. http://arxiv.org/pdf/1606.04120.pdf — Preceding unsigned comment added by 71.74.105.124 (talk) 00:01, 16 June 2016 (UTC)

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Clockwise ?
"The Whirlpool Galaxy has two, very prominent spiral arms that wind clockwise."

Under the assumption that the tip of a spiral arm is at the trailing end of an arm, these arms are winding counterclockwise.

Spope3 (talk) 23:46, 17 December 2023 (UTC)