Re: [math-fun] speed of our galaxy : 630 km per second but how can this be possible ?

Hello, let me rephrase the question, I know of course the concept of relative speed, even if we take into account that, at the moment of the big bang, the whole thing was going at the speed of light. Just take 1 galaxy and if we calculate the amount of kinetic energy to move a few kilometres per second , the amount of energy necessary is astronomical, how can we explain that ?, Where is the energy coming from ? Best regards, Simon Plouffe