The Theory of Relativity

How an observer moving in a strong gravitational field or at a high velocity perceives measurements of mass, lengths or the passage of time in a different way that an observer at rest would is the basic idea of relativity, developed by Albert Einstein in the early part of this century.

Special Relativity:

1. The laws of physics are the same for all inertial observers.

2. The speed of light is the same for all inertial observers, regardless of their motion relative to the source of the light.

General Relativity:

1. Special relativity governs the properties of space-time in regions where the gravitational influence of matter is neglible. However, space-time around a massive object is warped by gravitation.

2. There is no way to tell locally the different between acceleration and gravity. This is called the Equivalence Principle.

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