Questions tagged [gravity]

For questions about the attractive force between two objects which possess gravitational mass or energy.

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How did Bishop Francis Godwin Know About Mass and Gravity Pre-Newton?

In the answer to this question, a user provided a quote from the 1638 novel The Man in the Moone by Bishop Francis Godwin: The manner of our Travel to the Palace of Pylonas was more strange and ...
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How did Newton come up with mass terms in his gravitation formula and then what led to a confusion between inertial and gravitational mass?

Newton had realised that the acceleration due to gravitational force had to be inversely dependent on the square of the distance between two bodies. But how did he arrive at the conclusion that the ...
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What are the references for Riemann's discussion of gravity?

I've heard anecdotally that Bernhard Riemann was interested in applying his discovery/invention of Riemannian geometry to model gravitation about 50 years before Einstein managed to do so. In this ...
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Did the Idea of Universal Gravitation predate Newton?

"Baba wrote over 60 books, almost everyone on a different topic, writing on issues from astronomy, identified stars that European scientists technology could not discover until the late 1800s, ...
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81 views

Did Galileo state the principle of equivalence in full generality?

The weak equivalence principle (WEP) is often attributed to Galileo. Did Galileo ever state the WEP precisely? For instance as given here? The original principle, usually attributed to Galileo, ...
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How was gravity explained in Ancient Greek and Roman times?

Gravity is of course something that we can all observe. Stuff falls towards the ground. But not everything: some things like steam or smoke defy this force and instead float up. During Ancient Greek ...
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Was Lorentz aware of Le Sage theory?

I just wondered if Lorentz was aware of Le Sage theory. Seems like he uses similar math. Is there any direct quote from Lorentz regarding Le Sage gravity?
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Clairaut's proposed correction (reported as “D'Alembert's, Clairaut's and Euler's corrections”) to the Newtonian inverse-square law of gravity

From A.P. Yushkevich, "Leonhard Euler, his life and work", in "Development of Leonhard Euler's ideas and contemporary science", Nauka, Moscow, 1988, 15--46 (translation from Russian is mine): "One ...
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Who introduced passive/active gravitational mass?

Do you know who introduced the distinction between active and passive mass? In what circumstances the necessity for such distinction arose and when it was discarded? Wasn't it quite obvious that a ...
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Whose value of the distance to the Moon did Newton use?

I heard that Newton used the Moon acceleration to come up with his universal law of gravity, but in order to calculate its acceleration you need the distance to the Moon. Whose measurement of this ...
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1answer
155 views

What is a vortex?

Both Descartes and Llinas use the term of vortex to illustrate their theories, but none of them does it really specifically, and none of them is mentioned in the Wikipedia article on vortices. Could ...
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How would land “mount steadily in a continuous rise” if there was no difference between center of gravity and magnitude, according to Copernicus

In chapter 3 of "The Revolutions of the Heavenly Spheres" where Copernicus defines "how the Earth forms a single sphere with water", the Edward Rosen translation of the book states this. Moreover, ...
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Modification of Newtonian Gravity based on Maxwell's Theory

As is well-known, Maxwell's equations were already consistent with Special Theory of Relativity while the Newtonian law of Gravitation wasn't. It can be shown by solving the equations of Maxwell for a ...
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83 views

Who wrote down the equations governing gravity in a field language for the first time?

In his paper The search for unity: Notes for a history of quantum field theory [Daedalus 4, 106 (1977)], Steven Weinberg writes: The first successful classical field theory was based on Newton's ...
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How did Newton come up with the formula for gravity? [duplicate]

In high school students are taught the formula that describes the universal gravitational force $F=G\frac{m_1 m_2}{r^2}$. However it is not taught how and why Newton came up with it. Does Newton give ...
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How did Newton come up with his formula?

In high school students are taught the formula that describes the universal gravitational force $F=G\frac{m_1 m_2}{r^2}$. However it is not taught how and why Newton came up with it. Does Newton give ...
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1answer
205 views

Did Newton find geodesics on curved surfaces in Principia?

My question reffers to section X of book 1 of Isaac Newton's Principia, that deals with motion of particles on curved surfaces. I read that in proposition 56 Newton found the trajectory of a particle ...
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520 views

Was Newton aware his theory of gravity had flaws?

Was Newton aware of the fact that his theory of gravity did not account for the motion of Mercury?
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642 views

How did Galileo know that objects rolling down a ramp was an accurate model for free fall?

Galileo used balls rolling down ramps to study the relationship between time and distance traveled. However, without any knowledge of physics, it doesn't seem immediately obvious that the time-...
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Why did Einstein develop General Relativity?

I know that ultimately GR was validated by experiment. I'd like to know however, if there was any experimental discrepancy at the time that pointed to a conclusive flaw in Newtonian gravity, and which ...
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504 views

Did Einstein propose a perpetual motion machine to try to disprove quantum mechanics?

In response to quantum mechanics, so the story goes, Einstein proposed a machine, that, based on the uncertainty principle, was a perpetual motion. This showed that quantum mechanics was at odds with ...
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195 views

Was Einstein the first person to think of the equivalence of a ball drop in an accelerated elevator and a ball drop on Earth?

Consider the following figure taken from Wikipedia. Was Einstein the first person to think of the equivalence of a ball drop in an elevator with acceleration of $g$ and a ball drop on Earth? To be ...
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1answer
385 views

What 19th century developments contributed to the General theory of Relativity?

Regarding General Theory of Relativity, I'm interested to find out whether there are some contributors to this theory in 19th century or not. In fact I want to know whether there are some physicists ...
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421 views

Who was first to explain intuitively the inverse square law of gravity?

The surface area of a sphere is $4\pi r^2$ and when you increase the distance to a point charge the force diminishes like the $r^{-2}$. Who was the first person to realize this?
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Who was the first person to intuitively explain why gravity weakens by the square of the distance? [duplicate]

the surface area of a sphere is 4pir^2 and when you increase it the energy disperses by the square. Who was the first person to realize this?
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Robert Hooke and the Inverse Square Law

In borel, emile, 1922, l'espace et le temps, paris: alcan there is a claim that Robert Hooke discovered an inverse square relation of gravitating bodied prior Isaac Newton, who later applied it more ...
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541 views

Did Newton develop the concept of gravity first for falling objects or for celestial motion?

A benefit of Newton's concept of gravity as a force--despite the fact that it involved what was considered mysterious action at a distance--was that it explained objects falling to earth, and the ...
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Who discovered that different objects accelerate at the same rate due to gravity?

The concept of the constant acceleration for different objects due to gravity (at the same height and ignoring atmospheric effects) is usually attributed to Galileo. In reality, Galileo merely ...
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When did physics texts start to teach Kepler's $3/2$'s power law as a result of Newton's $1/r^2$ law of gravitation, rather than the other way around?

In modern physics textbooks, we teach Newton's laws of motion, then Newton's law of Universal Gravitation, and then Kepler's laws of planetary motion. Specifically, from the $1/r^2$ form of the ...