The Universe Was Speeding Up — Now It's Slowing Down
Imagine inflating a balloon. At first, it expands slowly; then someone gives a sharp blast of air, and it swells faster. But as the airflow weakens, the balloon's growth slows again. According to a new study, the Universe has behaved much the same way: after the Big Bang, it expanded, then suddenly accelerated, and now that acceleration is fading.