Why is C the symbol for the speed of light? (2004)

Causation is a bit of a troublesome concept in physics: https://plato.stanford.edu/entries/causation-physics/

I wouldn’t use causality as a foundational concept ontologically.

What’s true is that c doesn’t just apply to the electromagnetic field, but to all fundamental physical fields.

It sounds like a really nice (and the shortest possible) backronym.

https://en.wikipedia.org/wiki/Backronym

"Photons (being massless) have 100% of their velocity in the spatial dimensions and no velocity in the time dimension"

I kinda see what you're trying to say, but these words aren't a particularly good match for the math in special relativity. To an observer, any photon's velocity 4-vector looks like V = (c,c,0,0). That's a "c" in the spatial direction the photon's moving, and a "c" in the time direction. So, plenty of velocity in the time direction.

What is zero is the _proper time_ along a photon's trajectory through space & time. An observer who's co-moving with the photon (call me if you ever meet one, we can write a paper together) would see a) the photon holding still and b) no time passing.

special relativity is undefined at v = c. so no from a photons point of view the trip doesn’t happen in an instant nor does the length of the universe shrink to zero. there is no definition for a photons point of view. time dilation and length contraction only apply when comparing a moving frame of reference to one that is at rest and photons have no rest frame.

And when you think about c as the speed of causality, it becomes a lot more obvious why FTL travel/communicate is (almost certainty) impossible without breaking causality....

You are going faster than causality, of course it breaks.

The other option is to break relativity, which is what most science fiction media does, often accidentally.

That sounds like an interesting theory; is it yours, or do you have any citations / references you could share?

No, there is no causality anymore in quantum physics, since the EPR paradoxon was disproved.

c stands for the latin for for speed of course. causality is immediate, a higher speed than c. because it's logical, not measurable.

> c is technically the speed of causality.

How does this notion reconcile with seemingly instantaneous quantum phenomena like spooky action at a distance?

I never understood the appeal of title case. It brings nothing valuable, but sometimes leads to stupid mistakes like this, or raises ambiguities that hamper my reading.

I hope the American influence won't make this practice more common in British English. But it's not just about the country: The Washington Post has sane titles, like every British newspaper I've read, while The New York Times Has Elite Titles With Many Big Letters.

Technically it is the character with Unicode code point U+1D450. But HN arbitrarily removes it from the string upon submission, so, since we're approximating, C will do.

Yes, the very next sentence in the article:

The same Latin root is found in more familiar words such as acceleration and even celebrity, a word used when fame comes quickly.

yes! and that is composite

* "a-/ad-" towards

* "celeritas" speed

the second derivative, of sorts:

towards+speed

Indeed, and c_s ("c subscript s") is commonly used to denote the speed of sound.

I thought it was because C is fast (compared to most other languages)

C is for cookies, and that's good enough for me!

I wonder whether this is the Philip Gibbs that set up viXra.

So c = celeration, the derivative of acceleration.

A little too neat. It has the distinct aroma of lies told to children. (Not that I would have detected it myself, as a child.)