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Chandra Furthers Understanding About Dark Energy - Universe Today
A mysterious force, which astronomers call "Dark Energy", seems to be speeding up the expansion of the Universe. New observations from the Chandra X-Ray Observatory have independently confirmed this expansion by measuring the distances to galaxy clusters. It seems that the expansion of the Universe was slowing down after the Big Bang until 6 billion years ago; at that point the force of this dark energy took over and expansion began to speed up. The big mystery still remains... what is dark energy?