Stellar formation

Stellar formation begins in vast clouds of gas and dust called nebulae. Under gravity, these materials start to clump together, gradually contracting and heating up. As the core becomes dense and hot enough, nuclear fusion ignites—hydrogen atoms fuse to form helium, releasing energy. This process marks the birth of a new star. Over time, the star stabilizes, balancing gravity and the outward pressure from fusion, and enters the main phase of its life. This process can span millions of years and varies depending on the star’s mass and environment.