Here's why:
* Giant molecular clouds are vast, cold, and dense regions of space primarily composed of hydrogen and helium molecules, along with trace amounts of other elements.
* Instability arises from the cloud's own gravity. As the cloud's density increases, the gravitational pull between its particles also increases. This leads to a point where the cloud's internal pressure can no longer resist the inward gravitational force.
* Collapse: The gravitational instability causes the cloud to collapse upon itself. As it collapses, the cloud's core heats up due to the conversion of gravitational potential energy into thermal energy.
* Star formation: The collapsing cloud eventually forms a dense, hot core known as a protostar. The protostar continues to accrete material from the surrounding cloud, growing in mass and temperature. Eventually, the core becomes hot and dense enough to ignite nuclear fusion, marking the birth of a star.
