Special Relativity By SUSHANT KUMAR CHAUDHARY Department of
Special Relativity By SUSHANT KUMAR CHAUDHARY Department of Physics K. V. Sc. College, Uchchaith, Benipatti, Madhubani
Special Relativity vs General Relativity • In 1905, Albert Einstein developed his Theory of Special Relativity – How we move through a space changes on how we move through time • Special relativity refers to motion through a space at constant velocity • General relativity refers to accelerated motion through a space
Summary of Space-Time When you stand still, you are traveling at the maximum rate in time: 24 hours per day If you traveled at the maximum rate through space (the speed of light), time would stand still
Motion is Relative • Whenever we discuss motion, we must pick a reference point – Usually we refer to motion relative to the surface of the earth – Example: On a bus, you may travel 0 mi/h relative to the seat, but 60 mi/h relative to the road outside • Speed is a relative quantity, meaning its value changes based on location, or frame of reference
The Speed of Light is Constant • Light does not behave like the baseball thrown from the truck • No matter what the speed of the source of the light, light will always travel toward an observer at the same speed – If light is a constant, then space and time must be a single unit – Altering the rate of one will alter the rate of the other
Postulates of Special Relativity • First Postulate: All laws of nature are the same in all uniformly moving frames of reference – i. e. The behavior of a coin when flipped on a plane that is moving at constant velocity is no different than if flipped while standing still • No experiment confined in the moving reference frame itself can determine whether or not there is uniform motion
Space and Time Travel • Before theory of relativity, no one thought we could ever travel great distances in space – Our life span is too short to cover such great distances • Today, because of time dilation, we know that time for a person on Earth is different than time for a person in a high-speed spacecraft – Problem: The amount of energy needed to propel a spacecraft near the speed of light is too great.
Space and Time Travel • In the future, people may have the option to travel into space and return to a future century of their choosing • These people could never come back to the same era they left – Time travels only one way – FORWARD • Time and space, and therefore space -time, exist in the universe, not vice versa – Without the universe, there would be no space or time
THANK YOU
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