Is the Universe Going to Last Forever?

In the very, very earliest part of the universe, we believe that there was a rapid acceleration. And it stopped the field that we think caused it to accelerate, decayed away, and then the universe started to slow down. So for all we know, right now, whatever it is that's causing acceleration, since we haven't figured it out yet, it could decay away. We could be back in the universe slowing down and coming to a halt someday in the future. That I think that is the most encouraging answer I could possibly imagine"