#relativity

@cenobyte@mastodon.thirring.org I've spent the last hour-plus going through more of the "stuff" he links from the overview, and (a) I still have no way to tell if it makes sense or if it's just LLM-generated physics drivel, and (b) I get more and more concerned that "one self-educated non-physicist overturns all of modern physics and solves all outstanding problems", while hypothetically tenable, strains credulity. I mean, a long history of cranks "disproving" Einstein (dunno why they all hated relativity so much) and Dirac and everything else just screams "This guy is a nutter". The alarm bells are ringing. I really want people who actually understand this stuff to read it and tell me whether I can write this guy off as such a crank. But weirder things have happened. Einstein was just a clerk in a patent office who no one had heard of when he demonstrated the then-new and completely unsupported-by-evidence quantum theory, which had only been proposed to solve the (ultra)violet catastrophe, could actually explain the completely unrelated and then-unexplained photoelectric effect. He won the Nobel in physics for that - not relativity - and cemented quantum theory in place, even if he never liked it. A nobody who single-handedly stamped the dividing line between classical physics and modern physics. #crank #cranks #relativity #nutter

@jmax@mastodon.social You are likely going to regret that. (-: When discussing the energy–momentum relation, mass *is* by convention rest mass, as the usual formulation E^2=m^2×c^4+(p×c)^2 is in terms of rest mass m. The relation says that energy does not imply mass when m=0. Energy implies the momentum portion of the sum, which photons have, defined as p=h/λ. With m=0 the full form reduces to E^2=(p×c)^2 which after substitution for photon momentum becomes E=c×h/λ=h×f . But this does not become a statement about mass. It's fallacious to then substitute E=m×c^2 and solve for m to get m=h×f/c^2 . E=m×c^2 is a different reduced case for massive stationary objects (m>0, p=0), neither of which is the case for photons. Furthermore, the maths yields divergent γ=∞ Taylor series sums when u=c so thinking of K.E. terms for photons is aphysical. Energy-mass equivalence is a special form for the case of m>0, γ≠∞. Energy does not imply mass in the general case. @cstross@wandering.shop #physics #relativity