# Tag Info

Accepted

### Can Newton's gravity equation explain why black holes are so strong?

No you can't and the behaviour of bodies with mass and of light is completely different near a compact, massive object if you use Newtonian physics rather than General Relativity. In no particular ...

### What is the shape of orbit assuming gravity does not depend on distance?

Circular orbits are always possible for any central force law, but noncircular orbits would resemble rosettes. Here's a specific example for the case where the force is constant with distance: By ...
Accepted

### Intuition about why gravity is inversely proportional to exactly square of distance between objects

Imagine "gravity" spreading out in a sphere, like light from a bulb. For each doubling of the distance, the sphere has four times the area. The surface area of the sphere is proportional to ...

### Does the escape velocity formula take into account how a gravitationally bound object's distance to its primary increases before coming back down?

The escape speed is defined in Newtonian physics simply by demanding that the sum of kinetic energy at launch (ballistically, with no power applied thereafter) and gravitational potential energy at ...

### Can Newton's gravity equation explain why black holes are so strong?

I am not an expert in physics and the explanation of the others is excellent. However, I noticed a flaw in your reasoning which they did not address. You have written: Considering the Newton's Law of ...

### Does the escape velocity formula take into account how a gravitationally bound object's distance to its primary increases before coming back down?

Yes, escape speed is an instantaneous calculation at the distance 'r' from the center of the object, as that changes you have to recalculate your escape speed. For example, these are the escape ...
Accepted

### Gravitational acceleration inside a planet

You can use Gauss's law for gravitation to work out the gravity as a function of (interior) radius. $$\oint \vec{g} \cdot d\vec{A} = -4\pi G \int \rho\ dV\ .$$ What this means is that the flux of ...
Accepted

Accepted

### Why can't gravity repel things?

Apart from the field-theoretical standpoint presented by Stan, one can repel objects in a sense, when taking orbital mechanics into account. The slingshot maneuver extracts angular momentum and ...

### Intuition about why gravity is inversely proportional to exactly square of distance between objects

The validation is the same as the validation of any astronomical theory: it fits the data. Newton's law of gravitation was formed empirically, by observing the motion of the planets. In particular, ...

### At what distance does MOND Modified Newtonian Dynamics take effect?

There is no line at which things transition from Newtonian dynamics to MOND, it's more of a gradual continuous transition depending on the nature of the interpolating function $\mu(x)$: From Wikipedia ...

### What is the shape of orbit assuming gravity does not depend on distance?

There wouldn't be standard orbits at all. The Earth orbits the Sun because the Sun's mass dominates the local spacetime. By removing distance from the gravitational equation, the Earth would, with ...

### Gravitational waves vs. "normal gravity"

Acceleration isn't a property of spacetime per se. Two test particles at the same location can have different instantaneous accelerations, so just knowing that there is a passing gravitational wave ...

### Gravitational attraction of Sun on distant object

James K gave a good answer to this, but I just want to add that if the Sun was unmoving relative to the center of the Milky-way, it would fall towards the center along with your object. The sun ...