I find it hard to believe that light would be wieghtless. If it was it wouldn't interact with surrounding as it would have no dimensions. Therefore it would travel at infinite velocity, wouldn't diffract, reflect or refract. Also it wouldn't be affected by gravity as gravity needs a mass to act upon as that is how wieght is defined. Therefore if light is weightless it must also have no mass. Thus it follows that it wouldn't be affected by gravity at all for example the kind of gravity that tends to be found around black holes. Am I right or am i missing the point???