Talk:Spectrum

A conjecture: Is it because dispersed light that had passed through a prism looked ghostly that the word spectrum was introduced into the physical sciences? Michael Hardy 00:05, 18 Aug 2004 (UTC)

Page move

This is a very large dis-ambiguation page. Can anyone move this page to Spectrum (disambiguation) and Optical spectrum here?? 66.245.84.65 23:28, 16 Oct 2004 (UTC)

I don't think optical spectrum should be moved here. The optical spectrum is only the spectrum of visible light. The word spectrum is used far more generally than that even if one restrict discussion to electromagnetic waves. X-rays and radio waves also belong to the electromagnetic spectrum. Michael Hardy 00:09, 17 Oct 2004 (UTC)

Reverse page move

This page used to contain a nice article on the general concept of the spectrum. Someone seems to have overwritten that article by doing a copy-paste move of the former Spectrum (disambiguation) to this page. I ~~propose to reverse~~ have reversed this non-consensual copy/paste move and restored the original article. Comments?--Srleffler 20:17, 28 February 2007 (UTC)[reply]

TV industry

I was looking for Spectrum as used in the TV industry, "Following a simulcast period, analogue services are expected to be switched off around 2015. This will allow spectrum to be made available for new services on the DTT platform. HDTV is not expected to begin prior to analogue switch-off." I wanted to know if Specturm refers just to cable, or to Satellite at well. -C 16 Jan 2009 —Preceding unsigned comment added by 85.69.13.141 (talk) 10:30, 16 January 2009 (UTC)[reply]

You probably want Frequency allocation or Spectrum management, or perhaps Radio frequency if you're interested in the underlying physics.--Srleffler (talk) 13:19, 16 January 2009 (UTC)[reply]

Goethe and Schopenhauer

I have a couple concerns about the following text in the "Origins" section:

The word "spectrum" [Spektrum] was strictly used to designate a ghostly optical afterimage by Goethe in his Theory of Colors and Schopenhauer in On Vision and Colors.

First, the sentence is not really about the origins of the term, but rather is an example of a relatively late use of the term to mean "afterimage" rather than its more conventional meaning. Second, I don't believe either Goethe or Schopenhauer used the English word "spectrum", since both were writing in German. The sentence, as written, seems off-topic for this article, which is about "spectrum" in the sense of "a condition that is not limited to a specific set of values but can vary infinitely within a continuum." It could perhaps be mentioned in the next section as an example of a contrary use of the term, but at the least a citation is needed to a secondary source that discusses Goethe and Schopenhauer's odd usage and puts it in context. (Was this usage common among scientists at the time? Among artists? In English? In German? Is it totally unique to Goethe and Schopenhauer?)

The fact that the authors and their translators use "spektrum"/"spectrum" in an unusual way should definitely be noted in the article Theory of Colors. I notice the article itself seems to use the word in its modern sense.--Srleffler (talk) 06:29, 26 February 2010 (UTC)[reply]

Goethe's and Schopenhauer's use of the word "Spektrum" [spectrum] is more appropriate than Newton's use. An afterimage is ghostly. It is an appearance in which there is no material basis. Newton's band or series of colors is not ghostly in any way. Why is Newton's use of the word thoughtlessly assumed in the article as being correct?Lestrade (talk) 01:26, 25 October 2012 (UTC)Lestrade[reply]

Error in image?

There seems to be an error in image titled "The spectrum of a uniform light source rendered into the sRGB color space." (File:Rendered Spectrum.png)

If the numbers below the rendered rainbow colors stand for frequencies, then they are in the wrong order. Isn't red supposedly lower in frequency than ultraviolet?

Sirkkalap (talk) 15:39, 23 November 2013 (UTC)[reply]

The numbers are wavelength, measured in nanometers. Wavelength is inversely proportional to frequency, so red has longer wavelength than violet.--Srleffler (talk) 15:51, 23 November 2013 (UTC)[reply]

Link Rot

reference #2, "Imagine the Universe! Dictionary". NASA. is a dead link -max 68.70.51.178 (talk) 15:06, 2 June 2015 (UTC)[reply]

Thanks. I fixed it.--Srleffler (talk) 03:27, 4 June 2015 (UTC)[reply]

Is this an article on terminology?

@Srleffler is convinced that this is an article about terminology, and indeed the lead and part of the first two sections discuss the history of the word. But from Electromagnetic spectrum onwards (about 3/4 of the text), it is discussing science. In that respect, the lead doesn't represent the body very well. So is this an article about the term or the things it is referring to? And if the former, do the parts on science belong? RockMagnetist(talk) 22:07, 4 September 2015 (UTC)[reply]

I think you've answered yourself: it's at least in part about terminology; the fact that it's also more than that, makes it a broad-concept article -- one that still includes terminology, though. fgnievinski (talk) 02:50, 5 September 2015 (UTC)[reply]

I could be convinced otherwise, especially if you are trying to get rid of the terminology category altogether. Such categories tend to become catch-alls, since almost any article title can be taken as a "term", and therefore can be categorized as "terminology".

There are several different things that are called "spectra". Per Wikipedia policy, these specific topics need to be covered in separate articles, and they are. This article covers the concept of spectra in general—it's a broad-concept article. Since the broad concept is captured by a single word, I thought that would make it a "terminology" article. If you want to argue for a distinction between a broad concept article defined by a single term, and an actual terminology article, I'm open to that argument.--Srleffler (talk) 18:49, 5 September 2015 (UTC)[reply]

Thanks, you found the name for what I think this article is. There is a CfD on Category:Terminology going on, and I am not in favor of deleting the category because there are articles that do fit in it - for example, botanical nomenclature and -physis. But only articles for which it is a defining characteristic should be in it, and I think that doesn't apply to this article. RockMagnetist(talk) 00:20, 6 September 2015 (UTC)[reply]

Go ahead and remove the category, then. I'm fine with that.--Srleffler (talk) 00:23, 7 September 2015 (UTC)[reply]

Aspect of quantity is missing, and the distinction between qualitative and quantitative spectra.

Since this is an article that is basically an extended dictionary entry, then it should be really clear about the definition. It is not, because it does not include the most important point: that a spectrum is a representation or manifestation of adjacent quantities in a continuum. This might be implied, but is not really clear. Here is the definition of the word "spectrum" from the American Heritage Dictionary:

Spectrum: American Heritage Dictionary:

   1. Physics - The distribution of a characteristic of a physical system or phenomenon, especially:
       a. The distribution of energy emitted by a radiant source, as by an incandescent body, arranged in order of wavelengths.
       b. The distribution of atomic or subatomic particles in a system, as in a magnetically resolved molecular beam, arranged in order of masses.
   2. A graphic or photographic representation of such a distribution.   
   3.  
       a. A range of values of a quantity or set of related quantities.
       b. A broad sequence or range of related qualities, ideas or activities: the whole spectrum of 20th century thought.

The important phrases are italicized. It is much more distinct in this definition that a spectrum in science involves ascending/descending quantity of a given type. This article gives examples that imply this idea, but there is no general statement of it.

Definition #3 makes clear a distinction which is missing in the article, that is, the distinction between a spectrum as a range of adjacent and ascending/descending quantities, and as a sequence or range of related qualities. Related qualities cannot easily be said to be continuous, or ascending/descending, whereas quantities cannot be anything other. This seems to be a fundamental distinction which needs to be made as a general statement. — Preceding unsigned comment added by Contraverse (talk • contribs) 16:35, 4 April 2021 (UTC)[reply]

Internet?

Thus is not anything major, but can we add a link to the template at the top to Spectrum (brand)? That would be very helpful. VMDraper (talk) 14:21, 3 March 2023 (UTC)[reply]

That's covered by the link to Spectrum (disambiguation). The term has dozens of meanings. There is no reason to single out the brand for special treatment.--Srleffler (talk) 07:17, 4 March 2023 (UTC)[reply]