Hydrostatic equilibrium

Definition

Hydrostatic equilibrium is the balance between the inward gravitational force and the outward pressure within a star. This balance maintains the star's spherical shape and prevents it from collapsing or expanding uncontrollably.

5 Must Know Facts For Your Next Test

1. Hydrostatic equilibrium is essential for maintaining the stability of stars, including our Sun.
2. The inward force due to gravity is exactly balanced by the outward pressure from nuclear fusion in the star's core.
3. Disruptions in hydrostatic equilibrium can lead to stellar phenomena such as supernovae or collapse into black holes.
4. In the Sun, hydrostatic equilibrium ensures that energy produced in the core is radiated outwards evenly.
5. Understanding hydrostatic equilibrium helps astronomers predict stellar lifecycles and behavior.

Review Questions

• What forces are balanced in hydrostatic equilibrium?
• How does hydrostatic equilibrium affect the structure of a star?
• Why is hydrostatic equilibrium crucial for a star's stability?

Related terms

Gravitational Force:

The force of attraction between two masses, which in stars pulls matter towards the center.

Nuclear Fusion:

A reaction where atomic nuclei combine to form a heavier nucleus, releasing energy that creates outward pressure.

Stellar Lifecycle: The series of stages a star undergoes from formation to death, influenced by processes like hydrostatic equilibrium.