If you measure the red-shift of a star 10 million light years away, you measure the velocity of the star 10 million years ago when the stars were travelling faster (if we are willing to accept that the expansion of the universe is slowing down). This not such an outrageous idea since firstly it satisfies the conservation of energy principle and secondly we already accept that the planets and moons slow down with time. The slowing down of the expansion of the universe may simply be the sum of the slowing down of all the celestial bodies. Hence the existing red-shift data does not automatically prove that expansion of the universe is accelerating and there is therefore no need for Dark Energy. Any thoughts?