At the end of the 20th century, continued expansion took the lead as the most popular fate for the universe.
Space just keeps getting bigger, which allows time to keep rolling on.
Eventually even protons decay if giving enough time and all that's left is cooling radiation. At some point in the incredibly distant future all we have left is photons shifting towards red. This leads to the theory that at a certain distance objects are pushed away from each other, not pulled towards each other. It also suggests that all the matter in the universe will never collapse into only one black hole. Well, scientists are still trying to figure out if the universe will ever stop growing.