Here’s a physics riddle that I just thought up. The only problem is that I’m not sure what the answer is. But I like the question, so here we go:
Let’s say you have a very long piece of string, and it has absolutely no elasticity, it’s perfectly straight, and it’s totally frictionless. The string is floating out in the void of space and it takes light 1 year to travel from one end of the string to the other.
What if you and I are at each end of this string, and I pull on it (or I have an incredibly powerful machine do it for me). How fast would you feel the pull?
Intuitively, it seems like it would be instantaneous, but that can’t be right because it would be traveling faster than light. The answer is probably that it would depend on the mass of the string and the amount of energy in the pull, but that whatever those variables are, it would take at least 1 year, and that while that isn’t intuitive, our brains haven’t evolved to intuitively think about this kind of situation. But what if the string is massless? But then, if I add this premise, is it even a real question for physics anymore? Anyway, I thought it was a fun thought experiment.