We have measured both to higher accuracies than the deviation here. One way to measure the “cosmic speed limit” is by measuring how things like energy transform when you approach that speed limit, for example, which happens in particle accelerators all day every day.
I’m aware that we’ve caculated ‘c’ both by directly measuring the speed of light (to high precision), as well as indirectly via various formulas from relativity (we’ve directly measured time dilation, for instance, which lets you estimate c), but are the indirect measurements really accurate to parts per million?
Fortunately for me, wikipedia turned out to provide good citations. In 2007 some clever people managed to measure the c in time dilation to a precision of about one part in 10^-8.
We have measured both to higher accuracies than the deviation here. One way to measure the “cosmic speed limit” is by measuring how things like energy transform when you approach that speed limit, for example, which happens in particle accelerators all day every day.
I’m aware that we’ve caculated ‘c’ both by directly measuring the speed of light (to high precision), as well as indirectly via various formulas from relativity (we’ve directly measured time dilation, for instance, which lets you estimate c), but are the indirect measurements really accurate to parts per million?
Fortunately for me, wikipedia turned out to provide good citations. In 2007 some clever people managed to measure the c in time dilation to a precision of about one part in 10^-8.
Very good sir!