Washington Post is carrying this summary of new developments in the search for "dark energy", a force that seems to allow the universe to expand faster than it otherwise would. New observations using the Chandra X-ray telescope seem to confirm current predictions about this phenomenon. However, a lot is still very unclear, like whether it really is constant, or varies over distance or time, whether the universe will collapse, etc.

The time frame is around 10 billion years, so it's not like they're under a deadline or anything.