I have seen this before, and just saw a thread about the sped of light. The problem is that they say, "light has no mass" then conclude incorrectly on a number of issues. What may be worse is that no replies seem to address the source of confusion, light does have mass, zero rest mass yes, but mass it does have. The last I saw, was it should go infinitely fast have no mass; again no reply addressed the rest mass issue. WHY??