Perhaps my knowledge of the nature of gravity is a little shaky, but I'm pretty sure that the gravitational pull of a planet is directly related to the planet's mass. This is in contrast to the size of the planet, and also to the planet's density. If I'm wrong, please point me to a reliable source of information. Until then I'm going to continue saying that a planet with a mass 15 times that of earth with have a gravitational pull that is 15 times stronger that of Earth.
And actually, I went ahead and looked this up on wikipedia...
"According to the law of universal gravitation, the attractive force between two bodies is proportional to the product of their masses and inversely proportional to the square of the distance between them."
ie. gravity has nothing to do with density or size. Gravity has to do with mass. Gravitational Constants
Pretty sure I'm right
Perhaps my knowledge of the nature of gravity is a little shaky, but I'm pretty sure that the gravitational pull of a planet is directly related to the planet's mass. This is in contrast to the size of the planet, and also to the planet's density. If I'm wrong, please point me to a reliable source of information. Until then I'm going to continue saying that a planet with a mass 15 times that of earth with have a gravitational pull that is 15 times stronger that of Earth.
And actually, I went ahead and looked this up on wikipedia...
"According to the law of universal gravitation, the attractive force between two bodies is proportional to the product of their masses and inversely proportional to the square of the distance between them."
ie. gravity has nothing to do with density or size. Gravity has to do with mass.
Gravitational Constants