Hi, I've never posted on a forum before but I've sent this question to various scientists and not had any replies so I thought someone here might be able to help. It may be that to a trained scientist it is obvious, but if it is could someone please explain where I have gone wrong. The established wisdom is that the further away a galaxy is, the faster it is moving . As I understand it scientists have proposed that dark energy is probably responsible for this acceleration. However, after reading an article on dark energy, I suddenly realised that by my logic the universe isn't speeding up at all, it is actually slowing down! My reasoning runs thus:- (These velocities are only guesses to illustrate the reasoning) The furthest galaxy detectable with modern instruments is about 13.1 billion light years away, just for example let's say that its velocity is point five the speed of light (v = .5c). This is moving faster than galaxies only 1 billion light years away (v = .2c) These, in their turn, are going faster than galaxies only 1000 light years away ( v = .005c) If, instead of thinking a light year as away we think of it as ago, then a different sequence becomes apparent 13.1 million years ago the velocity was (v = .5C) 1 billion years ago it had slowed to ( v = .2C) 1000 years ago (v = .005C) If everything was moving much slower a thousand years ago than it was 13.1 billion years ago, how can it be speeding up? I know I'm wrong, I must be, I'm not a scientist I'm an artist! But for the life of me I can't work out why and it's making my brain hurt. I think the problem is that thinking of lightyears as a measure of distance, to the layman at least, can give the impression that everything we see is part of the universe as it is now. Whereas much (if not most) of it may no longer exist in the form that we observe.