Selbstgravitation

Selbstgravitation refers to the gravitational attraction of an object on itself. It is a fundamental concept in physics, particularly in astrophysics and cosmology. When matter is concentrated in a region, its own gravity pulls it inward. This inward pull is what can lead to the formation of stars, planets, and galaxies.

In a gas cloud, for example, if the density becomes high enough, the gravitational forces between the particles can overcome the internal pressure that would otherwise cause the cloud to expand. This leads to a collapse of the cloud, a process known as gravitational collapse. As the cloud collapses, its density increases, further strengthening the self-gravitation and accelerating the collapse. This process is crucial for stellar birth.

The concept of self-gravitation is also relevant in understanding the stability of celestial bodies. For a planet or star to maintain its shape against disruptive external forces, its own gravity must be sufficient to hold it together. The balance between self-gravitation and internal pressure (or other outward forces) determines the structure and evolution of these objects.

In a broader cosmological context, self-gravitation plays a role in the formation of large-scale structures in the universe. Initial small density fluctuations in the early universe are amplified by gravity, leading to the clumping of matter into galaxies and clusters of galaxies over cosmic time. Without self-gravitation, the universe would remain a diffuse, homogeneous soup of particles. The strength of self-gravitation depends on the mass and density of the object.