Produced by Einstein in 1915, the typical theory of relativity may be the modern theory of gravity. This can be a very complicated mathematical theory which in summary states that space and time, collectively called spacetime, is curved from the existence of matter as well as, and that the motion of matter as well as is relying on this curvature.

Special Relativity

When Einstein devised his theory, he previously three experiments at heart to check its predictions. One was the gravitational bending of starlight around the sun. According to general relativity, the road of starlight which grazes the top of the sun should bend by 1.75 arcseconds. This effect can be measured during a total eclipse. In 1919, Sir Arthur Eddington measured precisely this bending throughout an expedition by which he observed a total eclipse. This discovery made Einstein an instantaneous worldwide celebrity.



The next prediction is the precession of planetary orbits about the sun. In accordance with general relativity, the perihelion with the orbit of mercury should precess concerning the sun by 43 arcseconds per century. This effect was in fact observed just before Einstein's theory and unexplained until predicted through the theory.

Special Relativity

The next experimentally verified prediction will be the slowing of time because of gravity. This effect causes light to become redshifted in the presence of a strong gravitational field, i.e. nearby the the surface of a huge star. This effect is noticed in the spectra of massive stars. Taken up its extreme, this effect predicts the existence of black holes, i.e. objects that are so massive that nothing, not light, can escape from their gravity. Black holes have been observed indirectly now their existence is actually undisputed.