Has anyone noticed that at least two of the posts have switched around (something to do with the vB switchover, I assume)? Either that or I have ESP.
" If aliens in the Andromeda galaxy defined the concepts of mass, energy, and velocity the same way we do If aliens in the Andromeda galaxy defined the concepts of mass, energy, and velocity the same way we do…"
That’s a big “if”, seeing as that we have real-life examples of a couple of humans (my April 17 alter ego, and the guy who authored the recent mailbag question) who didn’t see any inherent relationship between energy and mass ime\distance. The aforementioned humans are not scientists, granted, and if we were we would be aware of where joules and other kinematically-derived energy units came from. If we didn’t have those units - if our only measure of energy were calories, for instance - Einstein’s equation would have a coefficient in it.
By the way, the above thread has gotten out of order. My incorrect supposition that Einstein used SI units was replied to by Strainger, ostensibly before I made it. Either Strainger broadcast his reply using tachyons, or the transition from UBB has messed up some of the chronological ordering.
Perhaps you’re right, but that constant would have a real physical meaning. It would certainly involve some other fundamental quantities like Boltzmann’s constant (or some suitable multiple), which expresses the fundamental relationship between energy and temperature (which can be defined with respect to dimensionless quantities like the number of accessible states in a system).
I guess you’re correct though, that the equation holds as is only if we think of energy as kinematic. If you’re a general relativist, you just take c and the gravitational constant to be 1, without dimensions. Then E = m, and masses and energies are expressed in terms of length (which works out to be, IIRC, a simple multiple–1 or 1/2, I think–of the Swarzchild (sp?) radius of the mass in question). The fundamental point is that energy and mass are proportional, not what the proportionality is.
Rick