8 ms·
c is constant, the speed of light is not. c is the speed of light in a vacuum, but it is not really about light, it is a property of spacetime itself, and ligh
by GuB-42 1y ago
c is constant, the speed of light is not.
c is the speed of light in a vacuum, but it is not really about light, it is a property of spacetime itself, and light just happens to be carried by a massless particle, which, according to Einstein's equations, make it go at c (when undisturbed by the medium). Gravity also goes at c.
- bigfishrunning 1y agoI've always considered C the speed of light and gravity goes at the speed of light, not that light and gravity both go C, which is a property of spacetime. This is a much simpler mental model, thanks for the simple explanation!
- Eldt 1y agoI've always thought of c as the speed limit of causality
- Sniffnoy 1y agoYou can think of c as the conversion rate between space and time; then, light (and anything else without mass, such as gravity or gluons) travels at a speed of 1. Everything else travels at a speed of less than 1. (Physicists will in fact use the c=1 convention when keeping track of the distinction between distance units and time units is not important. A related convention is hbar=1.) You can tell that c is fundamental, rather than just a property of light, from how it appears in the equations for Lorentz boosts (length contraction and time dilation).