Theory of Relativity

Theory of Relativity 

In relativity describe about motion. when something is moved it follow the relativity.

Classical theory of relativity

we cannot say that anything is at rest or in motion unless it has a reference point. for nothing that cannot be moved cannot be at rest unless it is compared to other things. for example: if a car passes in front of me, I will think that I am stopped and the car is moving, If an alien were to see me from the moon at this time, he would see that I am moving, car is moving in front of me and he himself is standing still. The farther we go, the more things seem to move. According to classical theory motion and speed are involved at the same time. 

Einstein describe about two theory of relativity.

• Special theory of relativity.
• General theory of relativity.

Special theory of Relativity(1905)

Inertial reference frame 

Speed of light is always constant. It is equal to 229 792 458m\s.  Einstein thought speed is equal to distance\time. suppose speed is same and distance is different so time is changed for balance the equation. According to Einstein if you are stop then the time will be different for you and if you are standing then the time will be different for you. for example if you take your rocket into space, when you come back, a lot of time has passed on earth. Due to speed of light constant ,time is not only effect length is also effect it is called length contraction.

special theory of relativity is called special when object is moved to close the speed of light or constant speed of light.

General theory of relativity(1907)

 Accelerated reference frame

Until the early 20th century, physics was mostly explained in term of Isaac Newton laws. According to Newton's theory, the planets of the Solar System would leave their orbits instantaneously, since there would be no gravity to pull them toward  the Sun. For Newton, gravity is a force that acts instantaneously regardless of the distance between bodies. 
Albert Einstein describe a new general theory of relativity. He imagined the three dimensions of space and the dimension of time together as a kind of fabric surrounding us, shaped

by the presence of celestial bodies. He called it space-time. This theory alternative the newton theory of gravity. According to Einstein according to general theory of relativity any object that wraps space-time around itself. due to this curve object attract each other.