An Overview of The Special Theory of Relativity
The Special Theory of Relativity is based upon two postulates:
- Principle of relativity: the laws of physics are the same whether
the observer is at rest or moving at a constant velocity.
- Principle of the invariance of the
speed of light: the speed of light in a vacuum is a universal constant. It
does not depend on the speed of the light source with respect to the observer.
These postulates imply that the Newtonian concept of absolute space and time is no longer valid. Instead, measurements of length and time depend on the relative speeds of the observer and the object involved. This leads to the two
relativistic effects known as the Lorentz contraction and time dilation. Due to the finite speed of light, there will also be the aberration of light and the Doppler Shift.
Another result of the theory is that objects with non-zero rest masses can
never travel at or beyond the speed of light.