A Summary of “Relativity: The Special and General Theory by Albert Einstein.”

“Relativity: The Special and General Theory” is a seminal work by Albert Einstein, published in 1915.

The book introduces and explains the two major theories of relativity: Special Relativity and General Relativity.

Special Relativity:

Principle of Relativity: The laws of physics are the same for all observers in uniform motion. There is no privileged frame of reference.

Constancy of the Speed of Light: The speed of light in a vacuum (denoted as ‘c’) is constant for all observers, regardless of their motion or the motion of the light source.

Key Concepts of Special Relativity:

Time Dilation: Time is relative and can dilate (slow down) for objects in motion relative to an observer.

Length Contraction: Objects in motion appear shorter along the direction of motion.

Mass-Energy Equivalence (E=mc²): The famous equation stating that mass and energy are interchangeable.

General Relativity:

Principle of Equivalence: There is no experiment a person can perform that will distinguish between being at rest in a gravitational field and accelerating in the absence of gravity.

Curvature of Spacetime: Massive objects like planets and stars cause spacetime to curve around them. Objects move along curves in this curved spacetime.