Special Theory of Relativity Presented By: Faiz Muhammad Abdul Bari What is the Special Theory of Relativity? • In 1905, Einstein sought to explain situations in which Newtonian physics might fail to deal successfully with phenomena, and in so doing proposed revolutionary changes in human concepts of time, space, and gravity. • To put it into simple words, special relativity is how light behaves in relation to different perspectives. Postulates of Special Theory of relativity • The laws of physics are the same in all inertial frames of reference. • The speed of light is a universal constant, regardless of the motion of any observer i.e. no matter how fast you move relative to the speed of light, you will observe the speed of light to be 3*10^8 m/s. What did Einstein actually do? • Introduced a new way to view: • Space • Time • Simultaneity • And changed the concept of time, being absolute! Galilean- Newtonian Relativity • Inertial Frames: the inertial frames in which Newton’s laws of motion are valid. • The relativity principle: the basic laws of physics are the same in all inertial frames of reference • Understood by both Galileo and Newton both • They believed in absolute space and time. What is the ground breaking idea? • Time is relative! • Events that occur simultaneously according to one observer can occur at different times for other observers. • Einstein discovered that there is no “absolute” time, it too depends upon the state of motion of the observer. • Einstein proposed space and time to be space-time, two concepts of the same thing. Time Dilation • Time dilation is a physical phenomenon in which time moves differently for different observers in the same inertial frame (in which there is no acceleration between them). • In time dilation, time moves slower for an observer who is in motion relative to another observer. • The concept of the time dilation effect comes from Albert Einstein's Theory of Relativity. Length Contraction When an object is moving, its length shrinks in the same direction as its velocity. This is called length contraction. Moving objects appear shorter. Relativistic Mass Relativistic mass is the change in mass of a body which is caused due to the change in the speed of the body. The relative change in mass is also perceived when the body is in motion. This concept is relativistic mass. Comparable to length contraction and time dilation a thing called mass increase happens when the object is in motion. In a nutshell • The effects of the Special Theory of Relativity • Moving clocks run slower. • Moving objects appear shorter. • Moving object’s mass increases. Thank You!
