How big is the Universe?

I recently heard that the distance between the furthest galaxies in our Universe is calculated to be 125 billion light years.Yet to my simplistic mind this is not possible. If the Big Bang occurred 13.7 billion years ago and nothing can travel faster than the speed of light, surely the furthest apart any 2 objects could be (moving in completely opposite directions) is less than 28 billion light years.I don't for one minute imagine that I can be right so either I'm missing something obvious or I guess it's a lot more complicated than that.Any explanations, anyone?

CavediverThanks to you and the others for your explanation.I have heard of this "balloon skin" analogy before, and it kind of makes sense in that respect, although how space can be like a balloon skin or how the distance between objects can grow without them actually moving still defeats my imagination!

Hi OniThanks for your input.Yes, I understand the idea of dots on a balloon (or raisins in a cake), although to my mind the dots are moving, because they are moving apart from each other as a consequence of the balloon enlarging. In other words, they are not moving under their own steam but they are hitching a ride on something else that's moving (the surface of the balloon in this case). That's why I still find it hard to get my head around the concept.