Gravity is an attractive force that affects and is effected by all mass and - in general relativity - energy, pressure and stress. Prefer newtonian-gravity or general-relativity if sensible.

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What observation(s)--if any--confirm that the types & concentrations of energy, which are influenced by gravity, are the same ones that cause gravity?

General relativity allows various forms of energy to participate in the gravitational force. What observation(s)--if any--confirm general relativity's notion that the various types & ...
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What level of mathematics would I need to understand the physics of a black hole? [duplicate]

I recently went to go see the movie Interstellar and was awed by the visualizations of the wormhole and the black hole Gargantua. I read that noted physicist Kip Thorne was a consulting producer on ...
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22 views

Does a time-evolving gravitational field or potential have any important/interesting effects?

I have learned from classical electromagnetism that a time-evolving magnetic field gives rise to a contribution to an electric field, and vice-versa. Do gravitational fields have an analogous effect ...
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Is the influence of gravity greater than light? [duplicate]

As the influence of gravity is infinite throughout the universe.is the influence of its force on a body very far away faster than the speed of light.suppose a star dies...is the influence of its ...
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Hydro-electric gravity problem - Is there a air-resistance-like force affecting water flow down a mountain making placing hydro-electric ?

Say I have a theoretical mountain with a river starting exactly at the peak. Gravity would act on the water, accelerating it down the mountain. There would also be a force limiting the water's ...
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117 views

How does Einstein's gravity work? [duplicate]

I'm a chemistry student interested in physics. Hope the question doesn't sound funny. As opposed to Newton's gravity, which doesn't explain how gravity works, Einstein explained gravity as a result ...
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Is an elastic, gravitating object stable?

As I understand, an object can contract under its own gravitantional pull. Then as it does so, different parts of the object must move with some velocity. This in turn means that their relativistic ...
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A central force which enables a torque on a sphere - is it still conservative?

Consider the following example: Two spheres (one big, other small) standing vertically on ground. At first, the small sphere is on top of the big sphere. Then, it starts to roll w/o slipping to ...
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121 views

What is the Casimir effect caused by gravity?

What is meant by a Casimir effect caused by gravity? Please explain me the concept in detail and how is it caused.
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How can spacetime affect massless entities? [duplicate]

Why is light affected and "bent" by spacetime if it has no mass or density?
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85 views

Potential Energy of Interaction Between a Sphere and a Particle Formula Derivation [closed]

A sphere of radius R has density described by ρ=ρ(r). Derive equation for pontetial energy of interaction between the sphere and some point particle of mass m which is at distance r from the center of ...
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Photons and gravity [duplicate]

A very powerful laser pointing to the empty space next to small object in space. The photons in the laser beam does not hit the object. Will the small object be gravitationally affected by that laser ...
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79 views

Bending of space vs. bending of a body - which is larger, and by what factor?

This is not homework, but is a problem I am asking myself. A long rod with known elastic material properties floats in flat space - suspended and kept in place by a number of massless ropes. Now we ...
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30 views

The stability of falling through a planet [duplicate]

Let's say that you were standing on Earth, and stepped into a hole that went perfectly straight down through the entire planet to the other side. Would the terminal velocity of your fall, and the ...
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36 views

why do everything tend to be stable? [duplicate]

Whenever I ask'why does a proton attract electron?' People say that 'because they are oppositely charged' But I want to know why do opposite Charges attract each other and tend to become neutralised? ...
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108 views

Definition of “nonlinear” in the context of perturbation of gravity

What exactly is the definition of a nonlinear perturbation when applied to a background spacetime metric? I have seen so called "linear perturbations" which look like $$ds^2 = -(1+2\Phi)dt^2 ...
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32 views

Does gravity get stronger with compression of matter? [duplicate]

I am wondering if gravity gets or would get stronger with ultra-compression (relativistic level) of matter? This may sound stupid but this is how my thought process went. Let us assume we have an ...
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47 views

To What Extent are Magnetism and Gravity Related and Unrelated? [duplicate]

I find many people (especially UFO-ologists) are quick to say there is an interplay between magnetism and gravity, especially when explaining antigravity of UFOs. On the other side, I see those who ...
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65 views

How would an observer feel the Einstein Thirring Lense Effect?

The Einstein Thirring Lense Effect, also known as Frame Dragging, is what happens when cellestial bodies have rotation. It states that when a body of mass is rotating around an axis it drags space and ...
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168 views

What Is the Physics principle behind dropping a stone into a cup of water?

I have been doing an experiment about relationship between drop height of a stone and the loss of water in the cup it lands in. I found that after dropping the same stone into a cup with the same ...
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609 views

How does gravity bend light [duplicate]

Assuming photons have no mass, as I believe they don't, how does gravity affect photons in order to bend them?
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87 views

What it would look like to observe people with a different time flows?

As I learned, that the bigger gravity source you are influenced by the more slow time ticks for you, the farther away you are from a gravity source the faster times ticks. So Imagine two different ...
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24 views

How does momentum effect velocity? [duplicate]

I'm in AP physics and we haven't even covered this yet so sorry if my question seems strange... I know $p = m v$, However right now I am writing a 2D physics engine and I am having some trouble with ...
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132 views

Visualizing bending of Spacetime around a heavy object

The commonly used example of viewing bent SpaceTime around a heavy object such as the Sun is the Trampoline. However, this image is limited as it shows only the bending below the Sun. What about the ...
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Materials on charged black brane

everybody! Does anyone know some good materials on charged black branes in AdS/CFT and the role of chemical potential in theses cases?
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How fast time goes in zero gravity [duplicate]

I understand that the effect of gravity is warping of space because of which object travels more through space dimension and less through time dimension, this is the reason for time slowing down in ...
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Gravity at event horizon [duplicate]

To find the gravity at Schwarzschild radius of a black hole, I used the below equations. Assuming escape velocity at event horizon is speed of light c and M is the mass of the black hole $$ v_e = ...
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At which gravitational acceleration would a diamond crystal lattice break down?

Gravitational acceleration can be upto infinite (which is at the Event Horizon of a Black Hole). On which least acceleration, would crystal lattice of diamond break down? Update: Please, don't apply ...
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electrostatic force vs gravitational force [duplicate]

I have question regarding the forces caused by electrostatic charges and gravity. From the explanation here in the link just by existing an object with mass distorts space-time. Will there be a ...
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88 views

What are laws regarding falling meteorites and the angles of descent?

I would like to know if there is any math / laws of physics governing the angle that a meteor falls on our planet. I doubt it falls towards the center of the planet, from what footage I've seen, it ...
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86 views

why ostriches cannot fly? physics explanation

I'm looking for a physics explanation concerning to the fact "The ostriches cannot fly". My statments: During the time interval $\Delta$t of the upward wingbeat, the ostrich drops a distance h ...
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What does one get when admitting negative mass? [duplicate]

So essentially, both gravitational and electric fields behave in exactly the same way. The only difference is that, while mass can only be positive, charge can be positive or negative. As I understand ...
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129 views

Calculating time of being in a lift only by weight & travel distance

If someone is in a lift and normally weighs 90kg, when the lift starts accelerating the person weighs 100kg. After the lift has maintained a constant speed for a while it starts slowing down. While ...
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67 views

How big could a bubble of air and water be in zero gravity? Assume air surrounds and fills a bubble of water

I am designing an all water planetoid for a new science fiction novel I am writing. The Planetoid is a spherical bubble of water filled with air, and covered by a sufficiently thick atmosphere to ...
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How can you calculate how fast a spinning ring/cylinder will accelerate a mass via gravitomagnetism? [duplicate]

Lets say you have a cylinder of length L, radius R, and mass M. How fast will it accelerate a mass of mass M2 that is entering the "throat" of the cylinder, considering the effects of ...
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related to projectile motion [closed]

I was given this worksheet from my teacher and well im finding it really tough so far .. the question below is just crushing my skull .. so i would appreciate it if you guys would guide me through it ...
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Properties of the Scalar Field in Scalar-Tensor Theories

I've been reading about scalar-tensor theories of gravity, such as Brans-Dicke theory, and I started thinking about the scalar field. Now, I know that the Higgs field is a scalar field, and of course ...
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Is gravitational acceleration less affected by relativistic mass increase? [duplicate]

Acceleration due to mechanical force will lessen due to relativistic mass increase as kinetic energy becomes significant near c. But if acceleration is gravitational, the gain in relativistic mass ...
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How do objects outside a spacecraft fall “around” the earth?

Now I get what microgravity is, how spacecrafts (even moon) fall around the earth to keep up themselves in their orbits and other related concepts after reading ...
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4answers
232 views

How does gravity slow light without an equal and opposite action? [closed]

This is regarding the gravity well sort of explanation. People claim that gravity doesn't slow light by saying it curves the road by which it travels but if space is indeed without properties and ...
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63 views

Effects of gravity on light [duplicate]

If gravity can bend light, why can't gravity slow light. At least momentarily? Wouldn't that give the illusion of the universe expansion speeding up?
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Does gravity act in the centre of the Earth? [duplicate]

If we we dig a hole from north pole to the south pole of the Earth and we throw a ball in this hole where would it stop? Will it come back on the surface or it will stop at the centre?
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Is there a mistake in this example in my mechanics textbook?

This is a worked example in my mechanics book: But I think this worked example is wrong. In the 6th line. shouldn't $X=4R$ as the expression for distance above the surface is $(X-R)$ and when the ...
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Relative effects of forces

Excuse me for my ignorance but I really couldn't find a solution. According to Einstein, every happening is possible to describe by both of interacted objects. Is there any other way to describe the ...
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Visualizing Tension in FBD — Rope With Mass

Asked to find the tension of a point that is halfway up a rope (where the rope has mass), given the system: The solution of the problem (FBD included) is as follows. In this diagram (Tm = tension ...
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4answers
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Gravity force between two objects with different mass

We know thanks to Newton that: $$F=G\frac{m_1\cdot m_2}{r^2}$$ Where $G$ is the Gravitational Constant that is about $6.673\cdot10^{-11}$ $m_1$ and $m_2$ are the masses of two different objects ...
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193 views

Does non-matter energy curve spacetime? [duplicate]

I know that matter (mass) curves spacetime, but do other forms of energy do the same? I.e. is matter the only form of energy that curves spacetime?
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Is Dark Energy Pushing Us Or Pulling Us? [duplicate]

This may seem silly, but how do they know that the effects we are seeing from dark energy, (which we only assume must be there due to observed acceleration), are not from gravity pulling us out from ...
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Could there be massive gravitons and in our spacetime? [closed]

My question is: Could there in principle be sub-groups of gravitons (if they existed) that has mass (and in our spacetime dimensions) such as those affected by electric or by strong force or other ...
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Gravity propagation speed [duplicate]

Related to: The speed of gravity? In the related question and in many other questions here, it seems as if the propagation speed of the gravitational interaction is $c$. To my understanding, the only ...