Local Gravity is my name for gravity at a specific height above sea level or normal ojects like metal balls.
To understand my concept of Local Gravity, let's go back to 1686 when Isaac Newton first published his equation for universal gravitation:
Where F is the gravitational force acting between two objects, m1 and m2 are the masses of the objects, r is the distance between the centers of their masses, and G is the gravitational constant.
Newton did not have a value for the gravitational constant. It was calculated in 1797-98, when British scientist Henry Cavendish conducted a series of experiments to determine its value.
Henry Cavendish in his famous experiment in 1797-1798, calculated the gravitation force between lead balls with a torsion balance.
This quote from Wikipedia explains the experiment:
The experimental apparatus consisted of a torsion balance with a pair of 2-inch 1.61-pound lead spheres suspended from the arm of a torsion balance and two much larger stationary lead balls (350 pounds). Cavendish intended to measure the force of Gravitational attraction between the two. He noticed that Michell's apparatus would be sensitive to temperature differences and induced air currents, so he made modifications by isolating the apparatus in a separate room with external controls and telescopes for making observations.
Data from the experiment was used to calculate the universal gravitational constant G.
Einstein's Theory or General Relativity in 1915 said massive objects cause a distortion in space-time, which is felt as gravity.
Today, Local gravity is calculated using Newton's equation. It is easier to use. Stellar gravity uses Einstein's equations.
Please read these essays in sequence: Time - Local Gravity - Experiments
Written By: Dennis Wilmeth
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