Whatever happened to the Big Crunch?

According to this news story, 'scientists' now believe that the universe will continue expanding forever.

How things change. When I was a physics student (about 20 years ago), the dominant theory was that the universe was expanding, following the Big Bang, but was decelerating in its expansion. The theory went that at some (future) time the universe would reach its maximum size and then begin collapsing in on itself, eventually ending up in the opposite of the Big Bang - the Big Crunch.

At the time it was taught to us as 'fact'. Now it appears that it was wrong and we have a new 'fact'.

"'A thousand years ago we thought the world was a bowl,' he said. 'Five hundred years ago we knew it was a globe. Today we know it is flat and round and carried through space on the back of a turtle.' He turned and gave the High Priest another smile. 'Don't you wonder what shape it will turn out to be tomorrow?'"

Terry Pratchett, 'The Truth'