# Gravity at the Earth center

Hi if an object was in the center of the earth would gravity be trying to pull it in all directions from it’s center out?
What are gravity’s characteristics there?
Virtually Yours

You would be weightless as Cecil says here: :

If you hollowed out a space at the center of the Earth, you would be weightless at within that space.

Yes.

And, to a first approximation, gravitational attraction cancels out at the centre of the Earth due to symmetry. It is, however, an unstable equilibrium.

Yes, but does it matter that much? If you have half the earth’s mass in one direction that you might want to move and half the earth’s mass in the opposite direction, your insignificant mass isn’t going to be able to counteract it. You’re going to remain motionless and weightless. This assumes you (or whatever object) were at rest in the center of the earth to begin with.

As in no feeling of action/pull on the body in any direction as we feel on the “outside”?
Would I feel my body trying to pull apart towards the mass all around me and that in essence causes my "weightlessness?

If you were inside a hollow space at the center of the earth, you would not feel gravity “pulling you apart.” Inside any hollow spherical shell, there is no gravitational force, even if you aren’t in the center.

I suppose you’re imagining the situation of someone being pulled in opposite directions, say by someone else grabbing each arm. Then you’d feel yourself being pulled apart. When field forces cancel, though, there is no “pulling” felt. Instead of the mass pulling you, think of the mass as creating a field of force, and the field pulling you. A zero field does not exert any force, even if it’s made by gigantic forces cancelling out.

If the force inside a sphere was different at different points, and only zero at the exact center, then you would feel “pulling” (although maybe not very much). That’s not how it works, though. Anywhere inside a hollow sphere the force is zero.

When a spaceship passes the medium point between earths gravity and the moon(on the way to the moon)it begins to accelerate as it feels the moons gravity more and loses the earth.
Newton surmised that if you whittled the earth away to the size of an apple the who would fall towards who.So I think it is the masses that attract one another smallest moving more rapidly toward the largest.
If to equal sized worlds were to come together in proximity and I was suspended between the two arms streched towards on and feet towards the other.would I feel a “pull” then in opposite directions of my center of gravity towards each mass or I am wrong in thinking of this pull effect(by pull I mean the weight that you feel when you hang your hands at your side and try to raise them)

Floating between two point masses is very different from floating inside a hollow sphere. If you are in a hollow sphere and move to the right, the right wall of the sphere gets closer, so each unit area (brick, molecule, or whatever) on the right wall pulls you with a stronger force. But since you’ve moved to the right, there is more mass to your left than before. So the two effects cancel out completely. The entire volume inside the hollow sphere is effectively weightless. Things will not “fall” towards the nearest wall.

On the other hand, if you are floating between two point masses and move to the right, the mass on the right gets closer. But you still have that same mass on your right, and the same mass on your left as you did before. So the net effect is that you get pulled towards the mass on the right.

What do you mean by unstable equilibrium in this case? Do you mean that a hollow at the center of the Earth would not last long?

If the hollow were offset from the center of the Earth, then there would be a slight gravitational pull in the direction of the center. Is that what you mean? We are assuming center, though.