HOW TO DEFINE GRAVITY ?

GRAVITY is natural phenomenon which causes our foot's still on ground holds our  atmospheric gas molecules , due to this gravity we are having days nights and also our moon revolving around the earth even the fusion process in sun is in role due to high gravity . 

than question is what actually causes gravity , which mechanism  makes it  to do what it's do .

first time this phenomenon was stated by Issac Newton . as Newton's law of universal gravity according to which it is a force which causes two object's to be attracted toward each other  whose magnitude is given proportional to product of both bodies and is inversely proportional to square of distance between them  -

                            F =Gm1m2/r^2

where F is the force due to gravity, between two masses (m1 and m2), which are a distance r apart; G is the gravitational constant. whose value is given by - 6.67408 × 10^-11 m³ kg^-1 s^-2 . 

 

 ^{although this formula works correctly Newton never explained how this force is born  he just stated that mass of any object causes it and pulls everything surround its to center of that mass  .} 

^{like our earth do it pulls object toward its center perpendicularly , consequence of it is very mind blowing moon is revolving around our planet because its not have enough speed so it can free it  self from pull of earth at same time don't have that less speed so earth can pull it down so its revolving around earth balancing gravity and speed of itself .}

 

^{Most recognized theory of gravity is given by Einstein in his general theory of relativity in which he described gravity as the distortion of spacetime fabric rather than as any force . recent experiments also proved that about gravitational wave who supports Einstein's claim .}

 

^{He also stated gravity as acceleration in his famous Elevator thought experiment in which he imagined elevator going down very fastly so he feels no weight at all  and when Elevator goes up rapidly opposite of it happens he feels his weight is increasing .}

^{so in condition of no gravity same thing happens you will feel weightlessness  all like when elevator goes down very fastly indeed you will start floating in it known as free fall (object acquires state of free fall   in space where gravity is infinitesimal ) . and if you are at the place where gravity is very high you will feel too much weight just like in condition of rapidly going up elevator .} 

^{well both this explanation just explains how gravity work rather than explaining what is it really the acceleration part will also appear you contradictory if you apply it on earth & sun in place of elevator and you because there is no physical contact in case of sun and earth and Einstein described it as space time .}

newton also wrote in his book where he talked about gravity that he is leaving this question on readers part that what causes gravity ?

^{and till now we don't know actually what gravity is  in real we just know its least and extreme effects like BLACK HOLE , WORMHOLE. if someday we know may be we can control it , but meanwhile we are just controlling it by spinning our space ship in space so it will grab us towards its inner surface .}