Changes

:::On the topic of assumptions, I'm not sure what else to say that I didn't say above. Special relativity does not ''assume'' that ''v'' cannot equal or exceed ''c.'' It ''assumes'' that the measured speed of light in a vacuum is the same in all reference frames. It then goes on to ''predict'' that under acceleration ''v'' cannot reach ''c.'' I agree, that alone would be a very difficult prediction to test. Fortunately, special relativity also ''predicts'' that proper time in a moving reference frame runs slower than proper time at rest, in proportion to ''v,'' and that prediction is ''not'' difficult to test. We accelerate particles with known half-lives to high fractions of ''c'' and then observe how long it takes them to decay. After enough such tests, the relationship between proper time in the moving frame and proper time at rest can be measured with a high degree of statistical precision. (This is known as the Rossi-Hall experiment, and was first done in 1940.)

:::On the topic of assumptions, I'm not sure what else to say that I didn't say above. Special relativity does not ''assume'' that ''v'' cannot equal or exceed ''c.'' It ''assumes'' that the measured speed of light in a vacuum is the same in all reference frames. It then goes on to ''predict'' that under acceleration ''v'' cannot reach ''c.'' I agree, that alone would be a very difficult prediction to test. Fortunately, special relativity also ''predicts'' that proper time in a moving reference frame runs slower than proper time at rest, in proportion to ''v,'' and that prediction is ''not'' difficult to test. We accelerate particles with known half-lives to high fractions of ''c'' and then observe how long it takes them to decay. After enough such tests, the relationship between proper time in the moving frame and proper time at rest can be measured with a high degree of statistical precision. (This is known as the Rossi-Hall experiment, and was first done in 1940.)

:::As for the other point about "absurd physical discontinuities" and the example given in the article — and believe me when I tell you I'm trying to say this as respectfully as I can — I'm afraid your math is simply flawed. The example given in the article is that if you take a massive particle, accelerate it to the limit c, ''and then also'' reduce its rest mass to the limit zero, you get a different momentum from that of a photon. At the risk of sounding pedantic, of course you do. Rest mass is not a variable in the equations of special relativity; it's not mathematically meaningful to take its value at a limit, because it's a constant. You could just as easily take the value of the gravitational constant ''G'' at the limit zero, but you wouldn't get physically meaningful results, because ''G'' does not vary. Saying that the equations break when you break the equations is, it seems to me, pretty tautological.--[[User:KSorenson|KSorenson]] 17:18, 11 November 2009 (EST)

:::As for the other point about "absurd physical discontinuities" and the example given in the article — and believe me when I tell you I'm trying to say this as respectfully as I can — I'm afraid your math is simply flawed. The example given in the article is that if you take a massive particle, accelerate it to the limit c, ''and then also'' reduce its rest mass to the limit zero, you get a different momentum from that of a photon. At the risk of sounding pedantic, of course you do. Rest mass is not a variable in the equations of special relativity; it's not mathematically meaningful to take its value at a limit, because it's a constant. You could just as easily take the value of the gravitational constant ''G'' at the limit zero, but you wouldn't get physically meaningful results, because ''G'' does not vary. Saying that the equations break when you break the equations is, it seems to me, pretty tautological.--[[User:KSorenson|KSorenson]] 17:18, 11 November 2009 (EST)