Escape velocity

Definition

Escape velocity is the minimum speed an object must reach to break free from the gravitational pull of a massive body without further propulsion. In astronomy, it's crucial for understanding phenomena like black holes where gravitational forces are extreme.

5 Must Know Facts For Your Next Test

1. Escape velocity from the surface of Earth is approximately 11.2 km/s.
2. For a black hole, the escape velocity exceeds the speed of light, making it impossible for anything to escape once within the event horizon.
3. Escape velocity depends on both the mass and radius of the celestial body.
4. The formula for calculating escape velocity is v = sqrt(2GM/R), where G is the gravitational constant, M is mass, and R is radius.
5. In curved spacetime around a black hole, traditional concepts of escape velocity are replaced by relativistic effects.

Review Questions

• What factors influence the escape velocity of a celestial body?
• Why can't light escape from within a black hole's event horizon?
• How does the concept of escape velocity change in curved spacetime around a black hole?

Related terms

Event Horizon: The boundary surrounding a black hole beyond which nothing can escape.

Gravitational Constant (G): A fundamental constant used in calculating gravitational forces and interactions between masses.

Relativistic Effects: Phenomena that occur at velocities close to the speed of light or in strong gravitational fields, predicted by Einstein's theory of relativity.