How fast can a black hole spin? If any object made of regular matter spins too fast -- it breaks apart. But a black hole might not be able to break apart -- and its maximum spin rate is really unknown.

Our Universe is expanding. Distant galaxies appear to recede from us at ever-increasing speeds. What is the rate of expansion? How long has it been expanding? What will be its ultimate fate? Two groups of astronomers are searching vigorously for answers to these fundamental questions using the Hubble Space Telescope (HST).