When did the solar nebula begin to collapse?

The solar nebula began to collapse approximately 4.6 billion years ago, likely triggered by shock waves from nearby supernovae or other cosmic events. This collapse led to the formation of the Sun at the center of the nebula, with the remaining material coalescing to form the planets, moons, and other solar system bodies. The process was part of the broader lifecycle of star and planetary system formation in the universe.