# Can gravitation force change its direction

#### parthivsmehta

force, can force change direction, if so can gravitation force change its direction,

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#### Artman

If all gravitational force effecting an object were reversed, it would do far more than just float up off the ground. It would smack into whatever building, tree whatever, rotating at it as the earth spins toward it. Missing that, it would be left in it's position in space at the time when gravity abandoned it just waiting for some planet or star or whatever to crash into it and burn it up.

#### keni

Actually, if the effect of gravity would suddenly be reversed the object in question would 'fall' upwards accelerating ca. 9.81 m/s^2. Although gravity would be reversed the inertia of the object would be left intact so the object would also keep moving along its previous path. This previous path is naturally the tangent of the curvature of Earth at the moment gravity was reversed. Knowing when gravity was reversed we could fairly easily calculate the speed (v = vx + vy + vz)of the object as a function of time.

#### Artman

Actually, thinking about it some more, with gravity reversed, the object would probably explode on a subatomic level (no gravity to hold itself together and anti gravity pushing it apart). Then all the pieces would continue seperating in their new inertial path (as Keni correctly pointed out).

#### neutroncount

Originally posted by Artman
Actually, thinking about it some more, with gravity reversed, the object would probably explode on a subatomic level (no gravity to hold itself together and anti gravity pushing it apart). Then all the pieces would continue seperating in their new inertial path (as Keni correctly pointed out).
Does a comet come apart in deep space? No. So why would anything else? Gravity doesn't 'hold' an atom together, the strong force and electromagnetic force do. Matter just reacts to gravity. So if gravity reversed, we'd all just float off the planet.

#### Artman

We don't know what the consequences would be for gravity being reversed. Objects are attracted to one another, not just to larger objects. Your comet has gravity even in deep space. Gravity is a weak force, but it seems to exist between all pieces of matter.

#### HallsofIvy

Homework Helper
What does being in "deep space" have to do with a comet holding together? A comet holds together because of the gravitational attraction of each part of it for the others. It is more likely to be disrupted when it is in "near space"- near to the sun or a large planet.

I agree that it is primarily strong and weak forces that hold nuclei together- and the electromagnetic force that holds atoms and molecules together. However at the scale of a "comet", it is gravity that is important.

#### Artman

What I am thinking is that if gravitation is reversed, all of the forces acting on the matter would be disrupted. What would happen if just one object ran counter to the laws of physics?

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