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.
I always remember c as the constant 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 mind worked before acquiring the knowledge!
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.
I did not know about that Latin term however I thought this came from the french since in the old time, many mathematicians and physicists used "celerite" instead of "vitesse" to talk about speed.
> 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.”
> 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).
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.
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 inserting more ads to bombard the reader with as well. Which further serves to incentivise adding filler text that is not really useful to the reader.
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.
> Weber apparently meant c to stand for "constant" in his force law, but there is evidence that physicists such as Lorentz and Einstein were accustomed to a common convention that c could be used as a variable for velocity. This usage can be traced back to the classic Latin texts in which c stood for "celeritas" meaning "speed". The uncommon English word "celerity" is still used when referring to the speed of wave propagation in fluids. The same Latin root is found in more familiar words such as acceleration and even celebrity, a word used when fame comes quickly.
Although the c symbol was adapted from Weber's constant, it was probably thought appropriate for it to represent the velocity of light later on because of this Latin interpretation. So history provides an ambiguous answer to the question "Why is c the symbol for the speed of light?", and it is reasonable to think of c as standing for either "constant" or "celeritas".
> Although the c symbol was adapted from Weber's constant, it was probably thought appropriate for it to represent the velocity of light later on because of this Latin interpretation.
Why do you say that?
> So history provides an ambiguous answer to the question ...
You provide an ambiguous answer, with no evidence (unless I misunderstand). That's not history.
The use of "c" as the symbol for the speed of light can be traced back to the pioneering work of the French physicist Augustin-Jean Fresnel in the early 19th century.
In his research on light and optics, Fresnel used the letter "c" to represent the speed of light in his equations and formulas. The choice of "c" was likely influenced by the Latin word "celeritas" and its association with speed.
Something 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.
I remember seeing a cartoon of Einstein at the blackboard on which the equation E=ma^2 (crossed out) then E=mb^2 (crossed out) and finally E=mc^2 with a beaming Einstein.
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.