I agree that this point is invalid. I have personally checked that if you take a massive particle, and make its rest mass tend to zero and its speed tend to c ''while keeping its energy constant'', its four-momentum approaches that of a photon. No discontinuity at all. Since this point has been raised 8 months ago and no opposition has been heard, I will delete point 4 from the list. If anyone is interested to see the details of my calculations, let me know and I'll put them in my userspace. [[User:Toph|Toph]] 09:38, 14 August 2010 (EDT) | I agree that this point is invalid. I have personally checked that if you take a massive particle, and make its rest mass tend to zero and its speed tend to c ''while keeping its energy constant'', its four-momentum approaches that of a photon. No discontinuity at all. Since this point has been raised 8 months ago and no opposition has been heard, I will delete point 4 from the list. If anyone is interested to see the details of my calculations, let me know and I'll put them in my userspace. [[User:Toph|Toph]] 09:38, 14 August 2010 (EDT) |