# Does gravity increase as mass get compressed and dense?

So far I know gravity is relative to mass but what if Earth was shrunk into the size of USA shall we experience the same gravity and weight or more? If not how can Earth ever become a black hole? I have read that if Earth was compressed to the size of a 50 cent coin it would become a black hole that not even light can escape from it's gravity. It's confusing.

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So far I know gravity is relative to mass but what if Earth was shrunk into the size of USA shall we experience the same gravity and weight or more? If not how can Earth ever become a black hole? I have read that if Earth was compressed to the size of a 50 cent coin it would become a black hole that not even light can escape from it's gravity. It's confusing.

Gravity (force of) is proportional to each mass, true, but it is also inversely proportional to distance squared, distance from center to center of the objects.

So if you shrunk the earth down, to say, 1/4 its present diameter, then the distances are 1/4 what they were, so force of gravity is 16 (4 squared) times stronger.

Shrink it down to 1/1000 its present diameter, then the distances are 1/1000 what they were, so force of gravity is 1000000 times stronger.

you can see as size becomes smaller, force increases by a large factor.

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• Yes. If mass is compressed, you can get closer to its center, so its gravity is stronger.

F = GMm / r^2

Gravity force depends on both mass and distance from its center. If earth's mass was squeezed to size of a golf ball, it would become a black hole.

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• No. only the radius of the mass changes making gravity stronger at the now smaller surface.(closer to the center of mass)

Not even our sun has enough mass to become a black hole, at minimum, near 3 times that mass.

Yes, if it were possible to shrink the mass of earth to the size of a golf ball, theoretically, it would become a black hole. Gravity alone can't do that.

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• The gravity at the surface of a planet (such as Earth) is based on the mass and the distance from the center (the radius of the planet).

If the Earth was compressed to a smaller radius but the mass remains the same, the total gravity is the same (total gravity is based simply on mass) but the gravity at the surface would increase.

Surface gravity = GM / r^2 where M is the mass of the planet, G is the gravitational constant, and r is the radius.

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