Chapter S3  Spacetime and Gravity

General Relativity

   Einstein 1915

How to think about curved spacetime

How mass affects spacetime

Special relativity versus General relativity

The laws of nature are the same for all reference frames.

The effects of gravity are exactly equivalent to the effects of acceleration.

Equivalence principle  1 2

Spacetime

3 space and 1 time = 4

         a worldline  1 2  more imaginative worldlines  1 2 3 4

But what if it is curved?

         Shortest distance on a sphere is a great circle  1 2

         Three geometries  1 2 3

Inertial frames are in straight worldlines.  Non-inertial [with gravity/acceleration] are curved.

The revolution

What we perceive as gravity is the curvature of spacetime.

Mass causes spacetime to curve and the curvature of spacetime determines the paths of freely moving objects.

Rubber sheet views.  1 2 black holes and event horizons.

Time dilation

Gravitational Redshift

Mercury’s orbital precession

Gravitational lensing total solar eclipse multiple images

Gravity waves  gravitational radiation   PSR 1913+16

         Detection by LIGO

Wormholes

Review Questions for Chapter S3