General theory of relativity and Space Time
Before the General theory of relativity there is no relation between time and Gravitation.Newton told that Time is absolute through the whole universe there is no role play time in universe
But after published special theory of relativity.Ten year after Einstein published General theory of relativity and tell that time and Gravity are related to each other. Einstein found that gravity effects time. Speed of time is depends on gravity.Newton could not able to explain gravity in the term of space time.Einstein said we need to understand more about gravity theory of General relativity totally changed the gravity concept.This theory explain motion of planets in a different way
According to the General theory of relativity "Space time spread through the whole universe in the form canvas when a mass would be placed on this canvas there make a curvature.
This curvature knows as Curvature of space time Now we can explain the motion of planets around the sun.
we know that Sun is the heaviest mass in Solar system due this heavy mass sun make a circular curvature with space time.
due to this curvature planets moving around the sun and this curvature is gravity.Same thing apply with Earth and Moonsince Earth has more than mass in the comparison of Moon
Moon always moving in the curvature of Earth. Jupiter has huge mass than other planet then the curvature with space time made by Jupiter is bigger than other planets then we can assume that due this bigger curvature Jupiter has more natural satellite
By the theory of Gravitation Newton never able to explain of orbital motion of mercy. We knows Mercury is the closest Planet to the Sun.The elliptical path of mercury around the sun is slightly shifts because space time is disturbed by the massive mass of Sun
We have study that light always travelling in a straight line but Einstein changed this perception about the direction of light.Einstein explain this how gravity changes the direction of light in his General theory of relativityif are looking another star behind sun we never determine the accurate location of that star due to gravity of sun. Gravity of sun bend the direction the light due to this where these are star seen but in
actual they do not be there.So General theory of relativity clear these fact gravity effects time ,gravity effect travelling direction of light.So in the modern physics Gravitation explain on the base of General theory of relativity besides the Universal law of Newton.
Time is not a absolute through the whole universe time is relative.Time blows with different velocity at the different places.Where gravity is more there time blows slow where gravity is less there time blows fast.