Naked Science Forum

General Science => General Science => Topic started by: ijaz on 05/12/2015 11:43:56

Title: What did GRT clarify about planet mercury??
Post by: ijaz on 05/12/2015 11:43:56

Planet mercury's example as testifying to the veracity of GRT , is prime; why is it so important? What exactly did GRT explain about Planet mercury ??

Title: Re: What did GRT clarify about planet mercury??
Post by: Atomic-S on 06/12/2015 02:28:59

Mercury is close enough to the sun that the deviation between Newtonian and Einsteinian theories of gravity becomes enough to be detected. Specifically, Newtonian gravity predicts elliptical planetary orbits, but Einsteinian gravity says that the orbits would deviate from that.  In Mercury, the deviation is detectable.

Title: Re: What did GRT clarify about planet mercury??
Post by: evan_au on 06/12/2015 06:32:56

Einstein says that the orbits are still ellipses, but due to time dilation close to a big mass, the direction of the major axis changes (precesses) over time, as seen by a distant observer.

See: http://en.wikipedia.org/wiki/Tests_of_general_relativity#Perihelion_precession_of_Mercury

Of course, for an orbit passing very near a very dense mass (like a black hole), a distant observer might see the orbit as more like a flower than an ellipse...