All Questions
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When is it appropriate to say Newtonian gravity is a force? When is it not appropiate? [closed]
Please help me understand the notion of force when it is applied to Newtonian gravity. From my understanding forces in physics involve interactions with at least 2 objects and can cause an ...
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1
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0
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65
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Does gravity actually have a ‘reaction force’? [duplicate]
By (my limited knowledge of) Einstein’s theory of General Relativity, as gravity is not a force but rather the effect of an object’s inertial path following a geodesic through curved spacetime due to ...
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4
votes
2
answers
695
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General relativity when can we approximate to Newtonian gravity?
Lets consider this scenario in deep void of space where other curvatures of large objects are negligible in this case and we bring 2 objects lets say $A$ and $B$.
We give it a force slightly lower ...
- 441
2
votes
6
answers
804
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Is the gravitational force a phenomenon or a theoretical invention? [closed]
We use to say that gravitational force is a phenomenon. But since the theory of General Relativity replaced Newtonian gravitational force, how is it possible for a phenomenon to be replaced by a ...
4
votes
3
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472
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How does relativity explain Newton's apple? [duplicate]
You must have heard the anecdote about the apple falling on Newton's head that led him to come up with the concept of Gravity. A long time later, Einstein upgraded it to the General Theory of ...
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0
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1
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76
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How do you find the distance between a massive object and its certain gravitational force?
Okay so I know I might've not phrased the question very well so I will give an example to try to make sense of it:
Say we have the moon and a place in space where the moon's gravitational force is 1,...
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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
2
votes
3
answers
139
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What is the gravitational pull if one has as much mass above them as below them? [duplicate]
I understand the previous responses to other answering if you were at the center of a planet, would you be weightless? Yes you would due to the forces of gravity pulling at you from all sides.
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1
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4
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How far apart do two objects have to be for there to be negligible force between them?
Inspired from the commentary on this question.
How far apart do two objects have to be for the gravitational force between them to be negligible? By negligible I mean, that it could never be ...
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Circular orbits in general relativity(GR)
Reading about Schwarzschild geodesics, I found that circular orbits are possible when the effective force
$$
F=-\frac{dV}{dr}=-\frac{\mu{c^{2}}}{2r^{4}}\left(r_{s}r^{2}-2a^{2}r+3r_{s}a^{2}\right)=0
$$...
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