Hi, Bret Busby wrote: > if you would be travelling toward a set of traffic lights, at > the speed of light, and the traffic lights were red, the Doppler effect > would cause them to appear green,
Your don't need to travel with full lightspeed to make red light green. The wavelength change would be from 650nm to 500nm i.e. ~ 0.769. https://en.wikipedia.org/wiki/Relativistic_Doppler_effect brings me to a "beta" of ~ -0.257. I.e. you need only 25.7 percent of lightspeed against the light beam direction from the traffic light if i can still do the math correctly. > and, so you could travel through them; I dimly remember a physicists joke that you will get a fat speeding ticket instead of a fine for traffic light violation. > you would have infinite mass, and so, whatever you hit, would be > obliterated... Whatever you hit has infinite mass, too. It's the theorie of relativity, after all. Both sides have the same right to say that the other is moving. > it is said to be constantly expanding and contracting That was a scientific fact in the 1960s. Nowadays the universe has been changed to expand forwever. Dark energy and such ... You'd need broad consensus among physicists to change it back. But consensus is dying out in these modern times. So for the time being, the laws of nature will have to stay as they are. I mean, imagine: Today an immense crowd of fat particles named Higgs Bosons gives mass to all and everyting. If you change that, then they all become unemployed and get into rebellious mood. > Isn't it E = (1/2)(M*(v**2)) ? That's kinetic energy as of Newton, not Einstein. Due to a grandfather regulation it is allowed to be still in use in small localities with slow movements. If you move faster than that, the factor M will grow according to the Lorenz transformation. This growth is due to energy which does not get into speed increase while you are approaching but never reaching lightspeed. The harder you try, the more mass you get. (There is a Nobel prize waiting for those who can explain why the Higgs bosons jostle so much around fast moving objects of non-zero rest mass ...) Have a nice day :) Thomas
