Does an object's density affect it's gravity?

Question

In space, if I have a small planet made out of some kind of metal(solid to the core), and a larger planet made out of sponge(porous to the core), would the larger object have more gravity because of it's size, or would their gravity be similar? The same can be applied to the idea of a marble versus a sponge I guess.

Does the density of an object affect the gravity it produces more than it's size, or is size the best measure of gravity forces?



PS: The sponge planet would not collapse and become denser, because it's a theoretical sponge planet.

Answer 1

p = M / volume = 3 M / ( 4 pi R^3 )
g = G M / R^2

M = 4 pi R^3 p / 3
g = (4 pi G / 3) R p
g = (2.7951E-10 m^3 kg^-1 sec^-2) R p

If the radius is held constant, then the gravity will increase in linear proportion with the average density. (The mass will increase as the density increases, of course.)

R^2 = { 3 M / (4 pi p) }^(2/3)
g = (4 pi / 3)^(2/3) G M^(1/3) p^(2/3)
g = (1.7339E-10 m^3 kg^-1 sec^-2) (M p^2)^(1/3)

If the mass is held constant, the gravity will increase in proportion to the density raised to the power of 2/3. (The radius will decrease as the density increases, of course.)

where g is the gravitational acceleration on the planet's surface in meters per second squared,
where R is the radius of the planet in meters,
where M is the mass of the planet in kilograms,
where p is the average density of the planet in kilograms per cubic meter,
where (pi) = 3.141592653589793...,
where G = 6.6728E-11 m^3 kg^-1 sec^-2.

Answer 2

Yes it does as the density would affect the object's mass. Gravity is a mass relationship and anything that would affect mass would affect gravity.

Larger the mass the larger the gravitational pull.

In the Jupiter example above the only problem with that example is that jupiter is SO much more massive than Earth that it has the required MASS to exert much more gravity...you would have same gravity if you compressed it into a dense pin head planet. HOWEVER if you had a planet the same size as jupiter that had a greater density by being solid instead of gaseous it would have a greater power of gravity

Answer 3

T R gives the best answer (Not to self: Vote for T R).

I like Jenna's answer also, but T R's was short and to the point.

M=VD. Gravity is a product of mass. So at the same distance from each planet (assuming equal mass), the gravitational pull would be the same. Now, the gravity at the surface of the denser planet would be greater, but the overall graviational pull of each planet (again assuming the only difference is density) would be the same.

Answer 4

At neutron famous individual densities, it may impression gravity. yet not earth type densities at factors sufficiently distant from the Earth. (assuming consistent mass for the Earth alongside with its atmosphere). Density is mass in line with unit quantity, so density is often correlated to mass for this reason gravity. In a superbly around completely homogeneous spherically symmetric international, gravity exterior the Earth does not be affected if one around shell shrank or greater to a diverse density (at consistent mass). The mass of the ambience is a few million millionth of the full mass of the Earth. Any outcomes of increasing it or lowering its mass on gravity would be factors in line with million. In destiny you would be able to to not want to ask a query and its negation in a similar placed up. Your final question is like asking:"what's the result if in 5 hourss i'm not the place i'm now?" It kinda relies upon on why and how the replace grew to become into made, does not it? Lightning bolt or a pass to to a sea coast in Hawaii would desire to the two reason you to pass away the place you're actually - one way on a stretcher to the morgue or in a bikini and flipflops. "someway" i think of you need one thank you to the different...

Answer 5

No, density does not affect gravity...Jupiter is less dense than Earth however it has a greater gravitational pull than Earth because of its immense size! The larger the object the stronger the gravitational pull. We ourselves have gravity....every object has some sort of gravity however it is not great enough for anyone to feel the effects.

Answer 6

Suppose if you have two planets, same mass, but different volumes. The greater volume planet will be less dense. The less-dense planet will mean that someone standing on the surface is further away from any given point within the planet's mass, so net the gravitational force pulling on the person will be less.

Answer 7

well, if we had 2 planets with the same size but different densities therefore different masses, the planet with the bigger density will have a stronger gravity.

Answer 8

I believe mass is the key, not necessarily density.