Quote:
Originally Posted by xelasnave
General Relativity is geometry and as such it can not control or influence space ... General Relativity revells in the fact it requires no force... well of course it requires no force because it is the observation and not the machinery of the Universe... General Relativity (as I understand it and I do not pretend to understand it very well which means I am presumptuious when even taliking about it) as I said is geometry and can only ever be how we record how mass and space relate... and mass and mass of course...
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General relativity is not geometry it is a gravitational field theory and forces
do exist in GR provided they are external.
The basics behind GR can be understood by anyone who has done year 12 physics and is familiar with electric fields.
If one considers the space between 2 charged plates, the electric field lines run perpendicular to the plates. The strength of the field is pictorially defined by the distance between each field line. If you put a charged particle between the plates, the field lines loop and converge or diverge depending on the charge of the particle.
With GR the gravitational field lines are defined as the trajectories taken by small mass "test particles". In zero gravity the particles move at a constant velocity in a straight line. If the particles moves into the gravitational field of a large mass, the trajectories deviate towards the centre of gravity of the large mass.
Einstein worked out that the trajectories of the particles in a gravitational field is the same as a particle moving from pt A to pt B in the shortest possible distance in curved space.
A particle moving in curved space along the shortest pathway does not see gravity as a force as it is travelling in an inertial frame of reference.
If however we add a second large mass to the picture which causes the particles to deviate from their trajectories, the particles experience gravity
as a force.
Regards
Steven