Point mass approximation
- For a point outside a uniform sphere, the mass of the sphere may be considered to be a point mass at its centre
- A uniform sphere is one where its mass is distributed evenly
- The gravitational field lines around a uniform sphere are therefore identical to those around a point mass
- An object can be regarded as a point mass when:
Its mass is so small its location is defined at a single point
- This applies for field lines around planets
Gravitational field lines around a planet
Gravitational field lines around a uniform sphere are identical to those on a point mass
