All About Inverse Square Law
Universe and Inverse are closely related, for the effects of known forces of universe are inverse in nature. Ever since Newton made a bold proposition that there is a force of attraction amongst the planets of planetary system, amongst different planetary systems and amongst the different galaxies and varies as Inverse Square of their distances, people began to correlate every activities of nature and predict its effect accurately. 1. Kepler’s laws
Tycho Brahe’s largest and most accurate collections of planetary observations helped Kepler to present the first ever natural laws
First law: Two planets P1 and P2 move on separate ellipses with the Sun at a common focus.
Second law: For planet P1 the line SP1 sweeps out equal area in equal intervals of time.
Third law: The square of the time taken by P1 and P2 to complete their respective orbits are in proportion to the cube of their respective semi-major axes.
First law indicates clearly what path the orbiting planets follow. Second law explains about the speed of a planet i.e. when the planet is nearest to the Sun (focus) speed is less e.g. at perihelion. When planet is farthest to the Sun e.g. at the aphelion the speed is more, so that at equal intervals of time the line joining the Sun and planet sweeps out equal areas. Third law is purely qualitative and compares the orbital motion of the different planets i.e. the ratio of square of period of revolution to the cube of semi-major axes is constant.
If T1 and T2 are periods of two planets P1 and P2 and a1 and a2 are their respective semi-major axes then
T12a13 = T22a23 =constant
The Kepler’s laws are a-posteriori i.e. derived by experience. Hence none of the laws state why planets follow elliptical orbit why not straight lines.
In those days one of the theories proposed was that the planets went around the elliptical orbits because behind them were the invisible angels beating their wings and driving the planets forward.
Newton freed nature from an all
Tycho Brahe’s largest and most accurate collections of planetary observations helped Kepler to present the first ever natural laws
First law: Two planets P1 and P2 move on separate ellipses with the Sun at a common focus.
Second law: For planet P1 the line SP1 sweeps out equal area in equal intervals of time.
Third law: The square of the time taken by P1 and P2 to complete their respective orbits are in proportion to the cube of their respective semi-major axes.
First law indicates clearly what path the orbiting planets follow. Second law explains about the speed of a planet i.e. when the planet is nearest to the Sun (focus) speed is less e.g. at perihelion. When planet is farthest to the Sun e.g. at the aphelion the speed is more, so that at equal intervals of time the line joining the Sun and planet sweeps out equal areas. Third law is purely qualitative and compares the orbital motion of the different planets i.e. the ratio of square of period of revolution to the cube of semi-major axes is constant.
If T1 and T2 are periods of two planets P1 and P2 and a1 and a2 are their respective semi-major axes then
T12a13 = T22a23 =constant
The Kepler’s laws are a-posteriori i.e. derived by experience. Hence none of the laws state why planets follow elliptical orbit why not straight lines.
In those days one of the theories proposed was that the planets went around the elliptical orbits because behind them were the invisible angels beating their wings and driving the planets forward.
Newton freed nature from an all