Albert Einstein's Theory of relativity

What is great about theory of relativity is that although is a mathematical theory it apply to every day life. If I had to explain to you in very simple words i would say that theory of relativity says that there is nothing constant in universe everything is effected by everything. Everything changes every minute every second and nothing is the way it was before.For example as soon you leave house for school you start experiencing new things, you are effected by kids you hang out with, or things that you did your self and based on that experience your decisions on some subjects could be different than the ones you made in the past. What I love about it is that you can not assume that great or bad things will last forever but what you can always know is that tomorrow you will start new adventure. But anyway that is how I like to understand that theory.
Here is the official scoop.

Tata

General relativity is a theory of gravitation developed by Einstein in the years 1907–1915. The development of general relativity began with the equivalence principle, under which the states of accelerated motion and being at rest in a gravitational field (for example when standing on the surface of the Earth) are physically identical. The upshot of this is that free fall is inertial motion: In other words an object in free fall is falling because that is how objects move when there is no force being exerted on them, instead of this being due to the force of gravity as is the case in classical mechanics. This is incompatible with classical mechanics and special relativity because in those theories inertially moving objects cannot accelerate with respect to each other, but objects in free fall do so. To resolve this difficulty Einstein first proposed that spacetime is curved. In 1915, he devised the Einstein field equations which relate the curvature of spacetime with the mass, energy, and momentum within it.

Some of the consequences of general relativity are:

* Time goes more slowly in higher gravitational fields. This is called gravitational time dilation.
* Orbits precess in a way unexpected in Newton's theory of gravity. (This has been observed in the orbit of Mercury and in binary pulsars).
* Rays of light bend in the presence of a gravitational field.
* Frame-dragging, in which a rotating mass "drags along" the space time around it.

Technically, general relativity is a metric theory of gravitation whose defining feature is its use of the Einstein field equations. The solutions of the field equations are metric tensors which define the topology of the spacetime and how objects move inertially.