Talk:Tully–Fisher relation

A good explanation published

To the curators of this page, please, read this preprint: https://www.academia.edu/8604226/The_Schwarzschild_Solution_to_the_Nexus_Graviton_Field Is already published here: http://www.worldscientific.com/doi/abs/10.1142/S0219887815500425

It deduces from a proposed graviton that v^4= G.M.Ho.c where M is the total barionic mass, and Ho is the Hubble constant

 — Preceding unsigned comment added by 186.59.70.167 (talk) 21:54, 6 March 2015 (UTC)[reply]

Completely Incorrect?

Tully-Fisher relation is not a method for measuring distances to spiral galaxies. The method is analyses of doppler shifting, and the Tully-Fisher relation is a relation between instrinsic brightness and the speed at which galaxies are rotating. Analyses of the doppler shifting allows determination of the radial velocity (speed at which it is rotating) and hence the Intrinsic brightness via the relation. This is then compared with the apparent magnitude to extrapolate a distance. This article needs completely re-wording in the immediate future. Jazzygm 16:38, 31 October 2006 (UTC)[reply]

It is both; it is a relationship between the intrinsic luminosity of a galaxy and the rotation velocities of the stars in that galaxy. This is the fundamental T-F relation. But it can be used to determine distances, because intrinsic luminosity is related to apparent brightness by the square of the distance. I agree with the "badly written / confusing" tag on the page, however; this page needs help. -- David W. Hogg 00:57, 4 January 2007 (UTC)[reply]

Okay, I blew ten minutes and re-wrote the article. I hope people add details. -- David W. Hogg 01:16, 4 January 2007 (UTC)[reply]

Open source compatibility note POV?

Tully-Fisher relation links as a reference to a PowerPoint file whence I found a specific fact (the T ∝ V^4 formula) that I didn't find in my other two sources. Because PPT is proprietary and Wikipedia is open-source / intended to be free and Free to all / has a significant non-Windows readership, I mentioned that the file works in OpenOffice.org. Is this statement POV, or fair notice for those without PowerPoint? --Geoffrey 02:16, 21 Apr 2004 (UTC)

Looks fine to me: IM(NS)HO it's more neutral to mention alternative methods of opening a file. Indeed mentioning the file format at all is an improvement on the usual situation where you click on a link, expecting HTML to pop up quickly, and your browser appears to sulk for ages while it opens some huge file: I'm all in favour of stating the format of an external link whenever it's anything other than HTML (or near equivalent e.g. PHP). --Phil | Talk 06:45, Apr 21, 2004 (UTC)

Pedantic note: as far as the browser is concerned, PHP is HTML - or, rather, normally is. It's just that it's generated by the server when you ask for it, not stored as a complete file somewhere. And in fact, a PHP file could (I believe) actually generate an image, or even a PowerPoint presentation, theoretically - making it even more important to label the link, as its target may well end .php. - IMSoP 14:31, 21 Apr 2004 (UTC)

PHP is capable of generating any kind of file. It's just oriented towards producing ASCII text, and formats derived from that (like HTML) -- Cyrius|&#9998 16:17, Apr 21, 2004 (UTC)

Just mention its type, not how to open it, the reader is not daft. Open Source POV is pushed in some articles around here, and that is tacitly accepted, but it shouldn't be. Pete/Pcb21 (talk) 19:24, 21 Apr 2004 (UTC)

Agreed, just metion the type. Its also openable in staroffice, microsoft office and with microsofts powerpoint viewer. Not listing these other opitions implies a bias towards openoffice. So best to just say that its a powerpoint presentation. I've also added in their original paper as a reference. --Albert White 13:39, 10 April 2006 (UTC)[reply]

Add more stuff?

There is more on the tully-fisher relation on scholarpeida [1], I don't really have much time, so could someone please write more about it using that article as a source? Pseudoanonymous (talk) 07:34, 8 February 2009 (UTC)[reply]

Dark matter

Shouldn't the article mention dark matter as a possible explanation and not just MOND? Dmcq (talk) 14:32, 5 January 2013 (UTC)[reply]

No, because dark matter doesn't explain it. The relation is between the observed matter and the velocity width. There would have to be a direct link between the amounts of dark and ordinary matter for the relation to be extended to dark matter. There is no theoretical reason for such a direct relation between the amount of dark matter and the amount of visible matter. Aarghdvaark (talk) 01:12, 6 January 2013 (UTC)[reply]

Graph confusing, vague and unsourced.

Overall the graph shown does not seem good evidence of a useful relationship since the slope is so poorly constrained ? Velocity scatter seems to have a range of about 3x ? graph has no explanation of 'h', or where the data comes from. Could we have a better/sourced graph ? The one at TFR by Tully is better described. - Rod57 (talk) 13:08, 9 January 2017 (UTC)[reply]

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Another country heard from

There should be a disclaimer that clearly states the method may NOT be accurate, since it is based upon redshift to obtain the rotational velocity of galaxies. REDSHIFT is highly questionable as the basis of distance measurement. — Preceding unsigned comment added by 97.73.100.18 (talk) 15:24, 22 June 2024 (UTC)[reply]