Stellar formation begins in vast clouds of gas and dust in space, known as molecular clouds. These clouds collapse under their own gravity, leading to regions of increased density. As the material gathers, it forms a protostar, which is a young star still in the process of forming. As the protostar continues to accumulate mass, its core temperature rises. When the temperature becomes high enough, nuclear fusion ignites, converting hydrogen into helium. This marks the birth of a new star, which will eventually enter the main sequence phase of its life cycle, shining brightly in the universe.