The Law Of Gravity: Universal Or Not?

Newton's law of universal gravitation states that every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. In other words, the force of gravity between two objects depends on their masses and the distance between them. This law applies everywhere in the universe and can be used to explain a wide range of phenomena, from falling apples to the orbits of planets and moons.

The law of universal gravitation applies to all particles in the universe

Newton's law of universal gravitation states that every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. In other words, the force is stronger when the masses of the particles are larger, and weaker when they are farther apart.

The law can be expressed mathematically as:

F = G * (m1 * m2) / r^2

Where:

• F is the gravitational force acting between the two particles
• G is the universal gravitational constant
• M1 and m2 are the masses of the particles
• R is the distance between the centres of the particles

The gravitational constant (G) is a key factor in the equation and is thought to be the same everywhere in the universe. It has been experimentally determined to be approximately 6.673 x 10^-11 N m^2/kg^2 or 6.674 x 10^-11 m^3/kg/s^2 in SI units.

The force of attraction is directly proportional to the masses of the particles

Newton's Law of Universal Gravitation states that every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres. This means that the force of attraction between two particles becomes greater as the masses of the particles increase, and decreases as the distance between the particles increases.

The equation for universal gravitation is:

F = G * (m1 * m2 / r^2)

Where F is the force of attraction between the particles, G is the universal gravitational constant, m1 and m2 are the masses of the particles, and r is the distance between the centres of the particles.

The value of the gravitational constant, G, is difficult to measure accurately. British scientist Henry Cavendish devised an apparatus to measure G in 1798, 111 years after the publication of Newton's Principia. Cavendish's experiment was also the first test of Newton's theory of gravitation between masses in a laboratory setting.

Newton's Law of Universal Gravitation applies to all objects with mass, regardless of size. It is a fundamental principle in physics and has been used to explain a wide range of phenomena, from the motion of planets and moons to the falling of an apple from a tree.

The force of attraction is inversely proportional to the square of the distance between the particles

Newton's law of universal gravitation states that every particle in the universe attracts every other particle. This means that any two bodies are attracted to each other by a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

The law can be expressed mathematically as:

> F ∝ m1 x m2 / r^2

Where:

• F is the force of attraction between the particles
• M1 and m2 are the masses of the particles
• R is the distance between the centres of their masses

The law of universal gravitation can be applied to explain a wide range of phenomena, from how an apple falls from a tree to the revolution of the moon around the Earth. It also helps scientists study planetary orbits and explain small perturbations in a planet's elliptical motion.

The law of universal gravitation is a fundamental principle in physics and has been instrumental in shaping our understanding of the universe.

The law was formulated by Isaac Newton in 1687

In 1687, Sir Isaac Newton published his law of universal gravitation, which states that every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres.

Newton's law mathematically describes the force of gravity, revealing a cosmos bound together by the mutual gravitational attraction of its constituent particles. The law is derived from Johannes Kepler's laws of planetary motion, the concept of "action-at-a-distance", and Newton's own laws of motion.

Newton's law of universal gravitation was formulated in his work *Philosophiæ Naturalis Principia Mathematica* ("the Principia"), first published on 5 July 1687. The publication of the law has been dubbed the "first great unification" as it unified the previously described phenomena of gravity on Earth with known astronomical behaviours.

The law states that:

> any two bodies are attracted by a force proportional to their mass and inversely proportional to their separation squared.

Newton's original formula was:

> {\displaystyle {\rm {Force\,of\,gravity}}\propto {\frac {\rm {mass\,of\,object\,1\,\times \,mass\,of\,object\,2}}{\rm {distance\,from\,centers^{2}}}}}

Where:

• {\displaystyle \propto } means "is proportional to"
• F is the force between the masses
• G is the Newtonian constant of gravitation (6.674×10−11 m3⋅kg−1⋅s−2)
• M1 is the first mass
• M2 is the second mass
• R is the distance between the centres of the masses

The equation for universal gravitation thus takes the form:

> {\displaystyle F=G{\frac {m_{1}m_{2}}{r^{2}}},}

Where F, m1, m2, and r are as defined above, and G is the gravitational constant.

The gravitational constant (G) is also referred to as the universal gravitational constant. The precise value of G was experimentally determined by Henry Cavendish. The value of G is approximately 6.673 x 10^-11 N m^2/kg^2.

The law was superseded by Einstein's theory of general relativity

Newton's law of universal gravitation states that every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. In other words, the magnitude of the force of attraction between two bodies is directly related to their masses and inversely related to the square of the distance between their centres.

While Newton's law of universal gravitation was a groundbreaking discovery, it was eventually superseded by Einstein's theory of general relativity. This theory, published in 1915, expanded on his earlier theory of special relativity and provided a new understanding of how gravity affects the fabric of space-time. According to Einstein, gravity is not an innate force of an object that can act over a distance, as Newton proposed. Instead, objects move towards each other due to the curves in space-time.

General relativity is a geometric theory of gravitation, describing gravity as a geometric property of four-dimensional spacetime. In this theory, spacetime is a four-dimensional object that obeys the Einstein equation, which explains how matter curves spacetime. The curvature of spacetime is directly related to the energy and momentum of the matter and radiation present.

One of the key predictions of general relativity is the existence of black holes. Black holes are regions of spacetime where space and time are distorted so extremely that nothing, not even light, can escape. This distortion is caused by the presence of extremely massive objects. General relativity also predicts the existence of gravitational waves, which are ripples in the metric of spacetime that propagate at the speed of light. These waves were first directly detected in 2016 by the Advanced LIGO team, providing strong evidence for the accuracy of Einstein's theory.

Another important consequence of general relativity is the gravitational lensing effect. This occurs when the path of light is bent by the curvature of spacetime as it passes near a massive object. This effect was first observed in 1919 when the positions of stars near the Sun were noted to shift during a solar eclipse. This discovery caused a sensation, propelling Einstein to fame.

General relativity also has important implications for our understanding of cosmology. The field equations of general relativity, known as the Einstein equations, can be used to model an expanding universe and have provided the basis for the discovery of the Big Bang and cosmic microwave background radiation.

While general relativity has been highly successful in explaining a range of gravitational phenomena, it does have limitations. One significant issue is its reconciliation with the laws of quantum physics. Currently, there is no self-consistent theory of quantum gravity that successfully unifies general relativity with the laws governing the very small particles described by quantum mechanics.

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