Which planet has the weakest gravitational pull?

Answer 1

There are 3 possible answers to this question: Mercury, Mars, or Pluto. The simple definition of gravity is the force of attraction between two objects. Two factors determine gravitational pull: 1) the mass of the two objects and, 2) the distance between the two objects. Gravitational pull is proportional to the product of the masses of the two objects. For example, gravitational pull doubles if either of the two masses is doubled. On the other hand, gravity grows weaker if the two objects are moved farther apart. It is inversely proportional to the square of the distance between them, or if the distance is doubled between the two objects, gravity is only 1/4th as strong. So both mass and distance matter when determining gravitational pull. The big variable that the question doesn't address is how far away are you from the planet when you want to know it's "gravitational pull". Do you want to know the gravitational pull at some constant distance in space from each planet's center, or do you want to know the gravitational pull at each planet's surface. Because each planet has a different diameter, the distance from the planet's center varies from planet to planet. Since both mass and distance matter, here are the qualified answers: Pluto has, by far, the least mass of all the planets, but Pluto is now considered to be a "dwarf planet" and is no longer to be considered as a regular planet. If it were to be considered, it would have the least gravitational pull of all the planets at both it's surface and at some fixed distance in space from it's center. Mars has slightly more mass than than Mercury but also has a larger diameter. The math works out that Mars has the least gravity at it's surface. Even less than the surface gravity of Mercury because of Mars' larger diameter. Mercury has slightly less mass than Mars and a much smaller diameter. The math works out that at some constant distance in space, Mercury has the less gravitational pull than Mars because Mercury simply has less mass. Because Mercury's diameter is smaller, which puts you closer to its center, that makes its surface gravity slightly more than Mars'.

Answer 2

Mars has the lowest surface gravity (0.376g), just a little lower than that of Mercury (0.38g). Although Mars is larger and more massive than Mercury, Mercury has a higher average density, dense enough to give it a slightly higher surface gravity.

Answer 3

Uranus