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General Relativity

General relativity is the theory of gravitation. It was published by Albert Einstein in 1916¹. This provides a unified description of gravity as a property of space and time, or spacetime. Spacetime is directly related to the energy and momentum of the matter and radiation are present. The relation is the Einstein field equations.

The simplest of Einstein’s field equations is

R_ab- 1/2 Rg_ab= 8πG/c^4 T_ab


R= R_cd g^cd

Currently, general relativity has emerged as a highly successful model of gravitation and cosmology. This has so far passed many unambiguous observational and experimental tests. However, there are indications that the theory is incomplete. Questions regarding quantum gravity and the question of the reality of spacetime singularities remain open.



1. Grandin, K. (n.d.). Retrieved from

Categories within General Relativity

Doppler Shift

Postings: 61

The doppler shift is the change in frequency or waves for the observer moving relative to the source.

Equivalence Principle

Postings: 14

The Equivalence Principle is any related concept dealing with equivalence of gravitational, inertial mass and Einstein's gravitational observed.

Relativity space travel and relativistic momentum

1. A ball (B) of mass m moves with velocity v relative to an observer (O). The momentum of B relative to O is p=mv according to Newtonian mechanics and p=gamma x mv according to Special Relativity. What do the above two theories predict for B's momentum if its speed equals c, the speed of light? 2. Alice travels from Earth to

Proper Time in Schwarzschild Metric

1. Consider a Schwarzchild black hole of mass M=15Ms where Ms is the mass of the sun. Two stationary clocks are on the same radial line, one at r1 = 300GMs and the other at r2 = 10Rs where Rs is the radius of the sun. (a) If 1000 seconds elapse on the clock at r2, determine the amount of time (in seconds) that will elapse on

Special Theory of Relativity

A.7 Give a very brief description of two observational tests of general relativity. A.8 An inertial observer sees a particle moving at a speed 3c/5. It then is seen to decay into two photons. Draw an accurate spacetime diagram to illustrate the situation before and after the decay takes place.