It is so, so refreshing to actually get an answer straight up instead of 6 paragraphs about the context, and how the author came to learn it, and what confusion might be, and how other constants have other names etc.
Its from 1997.
Why is c the symbol for the speed of light? (1997)
21–30 of 47 posts
Re: Why is c the symbol for the speed of light? (1997)
#22> The same Latin root is found in more familiar words such as acceleration and even celebrity, a word used when fame comes quickly. According to the OED, celebrity comes from the Latin “celebritās, [the] state of being busy or crowded, festival, games or other celebration characterized by crowded conditions, reputation, renown, fame, frequency or commonness.” https://www.oed.com/dictionary/celebrity_n?tab=etymology#9…
Which in turn may come from the same root.
> From Proto-Italic kelizris, perhaps root cognate with clueo, from Proto-Indo-European ḱlew-; alternatively (if the rare meaning of "swift, in rapid succession" is to be taken as primary) connected with celer (with Greek κέλλω from a root *kel-). Jackson An Etymological Dictionary of the Latin Language (1828:77).
Four citations given: https://en.wiktionary.org/wiki/celeber#References
Re: Why is c the symbol for the speed of light? (1997)
#23I always remember c as the c onstant speed of light [in a vacuum], but never pondered the actual origin beyond the perhaps rudimentary algebra “x, y, z are variables and a, b, c are constants”. I don’t think I thought c came from “constant”, because that’s a very English-centric view of science, but the annoying thing about reading a smart article like this is that it’s impossible to explore the depths of how your mi…
I think it would have been 'k' if it stood for "constant" since most of them were German-speakers or collaborating with them.
Re: Why is c the symbol for the speed of light? (1997)
#24I always remember c as the c onstant speed of light [in a vacuum], but never pondered the actual origin beyond the perhaps rudimentary algebra “x, y, z are variables and a, b, c are constants”. I don’t think I thought c came from “constant”, because that’s a very English-centric view of science, but the annoying thing about reading a smart article like this is that it’s impossible to explore the depths of how your mi…
As a tongue in cheek remark, it is English-centric to think that using c for constants is an English-centric view of science. French, Spanish, Italian, Portuguese, Romanian, all use the same word of Latin origin.
Re: Why is c the symbol for the speed of light? (1997)
#25Something related which I've not been able to find the root of - in some older British mathematics textbooks, F=ma is written instead p=mf (and this is definitely p meaning force and f acceleration and not an equivalent formula in terms of impulse or similar). I would love to know why these letters were used.
The p is probably Latin potentia or French puissance, but I'm not sure about the f!
The p stands for impetus; i was already used for inertia, and m is in the same equation for mass, so p was the next best letter to use.
Re: Why is c the symbol for the speed of light? (1997)
#26Earlier quoted context omitted.
Right! Most articles I stumble upon nowadays is filled with everything besides the answer until I scroll to the bottom.
Thank the SEO practices for that :( It is often understood that in order to rank on Google you have to have a certain length to the content. So then what do people do when they want to write about something that has a simple answer? Why, pad it with heaps of unnecessary paragraphs of garbage text of course. All in the name of ranking. And what’s more is, the longer the text is the more space is available for insertin…
Yep, my understanding is that Google interprets you clicking then going back within a short period of time as “I didn’t find what I was looking for.”
Re: Why is c the symbol for the speed of light? (1997)
#27Also related to “celery”, known as the fastest of all vegetables.
(Joke of course, celery comes from Greek selinon)
Re: Why is c the symbol for the speed of light? (1997)
#28> Apart from in relativity, the most pervasive use of c to represent a speed today is in the wave equation
This gives credence to what I was taught since high school, in French physics class: v=vitesse (speed), c=célérité (celerity).
Speed is used when talking about physical object movement, celerity is used when talking about propagation of a phenomenon (wave speed).
https://fr.wikipedia.org/wiki/C%C3%A9l%C3%A9rit%C3%A9
Though since c has come to specifically mean the speed of light is a vacuum as a notation, I see it used less often for other wave speeds when the constant is needed. Both speed and celerity are still used when writing and talking, with their respective meanings.
Re: Why is c the symbol for the speed of light? (1997)
#29It is so, so refreshing to actually get an answer straight up instead of 6 paragraphs about the context, and how the author came to learn it, and what confusion might be, and how other constants have other names etc.
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Re: Why is c the symbol for the speed of light? (1997)
#30Earlier quoted context omitted.
Thank the SEO practices for that :( It is often understood that in order to rank on Google you have to have a certain length to the content. So then what do people do when they want to write about something that has a simple answer? Why, pad it with heaps of unnecessary paragraphs of garbage text of course. All in the name of ranking. And what’s more is, the longer the text is the more space is available for insertin…
Yep, my understanding is that Google interprets you clicking then going back within a short period of time as “I didn’t find what I was looking for.”
I mean, if you go back I'd assume you didn't find the answer. If you close the tab, that's a different thing, and tells me you did, in fact, find what you were looking for.