All Questions
Tagged with newtonian-gravity general-relativity
227
questions
34
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4
answers
8k
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How can we recover the Newtonian gravitational potential from the metric of general relativity?
The Newtonian description of gravity can be formulated in terms of a potential function $\phi$ whose partial derivatives give the acceleration:
$$\frac{d^2\vec{x}}{dt^2}=\vec{g}=-\vec{\nabla}\phi(x)=\...
- 1,406
23
votes
4
answers
3k
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Is it possible that antimatter has positive inertial mass but negative gravitational mass? [duplicate]
Newtonian mechanics seems to allow for both positive and negative gravitational mass as long as the inertial mass is always positive. The situation is analogous to electrostatics but with the ...
- 2,403
20
votes
7
answers
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Is Newton's Law of Gravity consistent with General Relativity?
By 'Newton's Law of Gravity', I am referring to
The magnitude of the force of gravity is proportional to the product of the mass of the two objects and inversely proportional to their distance ...
- 6,000
18
votes
3
answers
673
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Comparing predictions and reality for the gravitational attraction due to light beams
While doing some on-the-side reading, I stumbled across this question: Do two beams of light attract each other in general theory of relativity?. Great question and a great, easily understandable ...
- 24.5k
18
votes
2
answers
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Newtonian gravity from the holographic principle?
Can one understand Newton's law of gravitation using the holographic principle (or does such reasoning just amount to dimensional analysis)?
Following an argument similar to one given by Erik ...
- 5,925
15
votes
8
answers
2k
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What is the true nature of gravity? [closed]
In 17th century, Sir Isaac Newton gave us the universal law of gravitation which stated that gravity is an inverse square force. In 1915, Albert Einstein recognised gravity as a curvature of space-...
- 255
13
votes
4
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Can a black hole be explained by Newtonian gravity?
In the simple explanation that a black hole appears when a big star
collapses under missing internal pressure and huge gravity, I can't see
any need to invoke relativity. Is this correct?
- 1,436
13
votes
2
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Newtonian gravity vs. general relativity: exactly how wrong is Newton?
Is there a simple function I can use to describe the difference between simple Newtonian dynamics and the actual observed motion? Or maybe some ratios for common examples of, say, the motion of stars ...
- 679
13
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1
answer
3k
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Gravitational Constant in Newtonian Gravity vs. General Relativity
From my understanding, the gravitational constant $G$ is a proportionality constant used by Newton in his law of universal gravitation (which was based around Kepler's Laws), namely in the equation $F ...
- 359
12
votes
1
answer
589
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Newton's law of gravitation in de Sitter space
Given two masses $M$ and $m$ (with $M\gg m$) in a de Sitter background with cosmological constant $\Lambda>0$ and positive spatial curvature ($k=+1$). What is the corresponding (semiclassical "...
user56224
11
votes
4
answers
878
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Can we disprove Artificial Gravity (like in the movies) with a thought experiment?
Suppose you have a Device that creates an 'artificial gravity' (AG) inside a Box, with these properties:
the system does not use inertial forces (like centrifugal force) or a huge mass to create AG
...
- 2,132
10
votes
4
answers
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Similarity between the Coulomb force and Newton's gravitational force
Coulomb force and gravitational force has the same governing equation. So they should be same in nature. A moving electric charge creates magnetic field, so a moving mass should create some force ...
- 1,975
10
votes
2
answers
2k
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Bending of light - photon's inertia instead of mass
Using classical mechanics, the formula for gravitational attraction is
$$F = G\frac{m_1m_2}{r^2}.$$
This formula does not work for photons, and we need to use Einstein's theory of gravity to ...
- 1,582
9
votes
5
answers
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Resolving General relativity and Newtonian mechanics on a computer [closed]
I know this is considered an old subject long ridiculed by many as the folly of layman. But I work in the field of computer simulation, specifically in producing fully functional 3D interactive ...
- 99
9
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3
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Contradiction in negative mass interactions according to GR
I quote Sabine Hossenfelder:
Gravitation is a spin-2 interaction. It is straightforward to see that this means that like charges attract and unlike charges repel. The charge of gravity is the mass. ...
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