I thought others might be interested in an old educational paper and fim demonstrating that you can't accelerate material objects past c. Bertozzi, Speed and kinetic energy of relativistic electrons, Am. J. Phys. 32 (1964) 551 The Ultimate Speed - An Exploration with High Energy Electrons - Abstract: Using a Van de Graaff electrostatic generator and a linear accelerator, the speeds of electrons with kinetic energies in the range 0.5-15 MeV are determined by measuring the time required for the electrons to traverse a given distance. The measurements show the existence of a limiting speed in accord with the results of special relativity. The kinetic energy, determined by calorimetry, verifies that an electric field exerts a force on a moving electron in its direction of motion that is independent of its speed. The film is honestly pretty dull -- it doesn't have the sense of humor that I associate with the old PSSC films from that period. It is nice, however, as a way of showing people very concretely what happens when you try to accelerate a material object past c. It makes it clear that this isn't just a matter of speculation. You can see all the hardware, cables, etc. The paper is easy to find online, although possibly illegally if your country's copyright laws are as repressive as mine.