A new study of the movement of faraway galaxies has opened a window on a time billions of years ago when the universe\'s rate of expansion began speeding up. Detailed observations of the changing distance between galaxies revealed that the mysterious acceleration of space, which began five to six billion years ago, perfectly matched predictions made by Einstein in 1916. The new measurements, presented at the National Astronomy Meeting in Manchester, show that the universe is expanding at an ever-increasing rate and that the structures within it, such as galaxy clusters, are also growing. The findings match Einstein\'s general theory of relativity in which he proposed the rate at which galaxies should be drawn towards one another and at which the universe ought to expand. Will Percival, of Portsmouth University, said: \"What our results mean is that within our model, which is based on general relativity, we have found that the universe behaves exactly as we would expect it to. Its rate of expansion fits exactly within general relativity, and the growth of structures within the universe also matches perfectly.\" Beth Reid, of Nasa, added: \"We already knew that the predictions of general relativity are extremely accurate for distances within the solar system, and now we can say that they are accurate for distances of 100 million light-years. \"We\'re looking a billion times further away than Einstein looked when he tested his theory, but it still seems to work.\"