It is a common believe that time passes equally for everyone and every frame of reference is relative. In fact these ideas formed the base of classical physics. In modern physics point of view, these ideas are just illusions. They only apply to conditions we all are aware of, i.e the familiar situation. In fact Time and Space are not absolute. They are also relative.

Einstein gave his Special Theory of Relativity (STR) in the year 1905. It stated that everything is relative except for Speed of light which is absolute. It also explained the phenomenon of Time Dilation and Space Time. Einstein's most famous equation E= mc

^{2}is a direct result of Special Theory of Relativity. This theory was named Special because it applied only to Special Frame of reference.

The major predictions of special relativity are:

1.

**Relativity of simultaneity:**Observers who are in motion with respect to each other may disagree on whether two events occurred at the same time or one occurred before the other.

2.

**Time dilation**(An observer watching two identical clocks, one moving and one at rest, will measure the moving clock to tick more slowly).

3.

**Length contraction**(Along the direction of motion, a rod moving with respect to an observer will be measured to be shorter than an identical rod at rest), and

4.

**The equivalence of mass and energy**(written as E = mc

^{2}).

Before going further and studying Special Relativity, it would be helpful for you to first learn the basics. Please refer Pre-Relativity to study classical Physics, nature of light and Particles so that you have better understanding of Special Relativity.

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