tähtienmuodostusta

Tähtienmuodostusta, known in English as star formation, is the process by which dense regions within molecular clouds in interstellar space, fragments into smaller units that eventually become stars. These clouds are composed primarily of gas and dust, with hydrogen and helium being the most abundant elements. The process begins when a region of the cloud becomes unstable, often due to external triggers such as supernova shockwaves or galactic collisions. Gravitational forces then cause the unstable region to collapse.

As the cloud collapses, it fragments into smaller, denser clumps. Each clump continues to contract under its own gravity, and its internal temperature and pressure increase. Eventually, the core of a clump becomes hot and dense enough for nuclear fusion to begin. This is the point at which a star is born. The outward pressure from the fusion reactions balances the inward pull of gravity, stabilizing the star.

The time it takes for a star to form can vary significantly, from a few hundred thousand years for the most massive stars to tens of millions of years for stars like our Sun. The surrounding gas and dust that did not form the star often coalesce into a protoplanetary disk, from which planets can eventually form. Therefore, star formation is a fundamental process not only for the creation of stars but also for the formation of planetary systems.