• October 25, 2007

    Episode 125: HubbleWatch for October 2007

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    Astronomers now know that that the expansion of the universe is speeding up, as though it were being pushed by kind of strange anti-gravity. Ten years after the discovery, scientists are still trying to find out what this mysterious force, called "dark energy," might be. The more scientists study the tiny galaxy I Zwicky 18, the older it looks. The galaxy has an odd combination of young and old stars, leaving astronomers puzzled about its late star formation.