Why do all the planets have different gravities?

Answer 1

The larger the planet mass, the bigger force of gravity it has. If you went to the moon, your weight would change but your mass would not. Mass is measured in kg, lb etc and Weight is measured in Newtons. Newtons is your force, that's why you can float around on the moon, as because it is so small, it has very little gravity. Your weight, in Newtons, would be much less.

Yes.

Talking about the "amount of gravity" however is very ambiguous and unscientific. Mostly you can refer to the gravitational acceleration a certain planet has on other objects. On earth it is 9.81 m/s or 22.7 ft/s. On the moon it is a sixth of that, being that the moon is smaller and less massive.

Mathematically we can define the gravitational acceleration, most often symbolized by a lower case g as:

░░░░░M

g = G ──

░░░░░R2

Where G is the gravitational constant (6.67x10-11 Nm2/kg2), M is the mass of the body, and R is the radius of the body.

Mercury does not have an atmosphere. But Titan (Saturn's moon) is smaller than earth, yet its atmosphere is denser than ours.

Answer 2

Planets have different gravities because their masses and sizes are different. Gravity is directly proportional to mass, meaning that planets with more mass have stronger gravitational pulls. Additionally, the size of a planet affects its gravity since gravity weakens as you move away from the center of mass.

Answer 3

The surface gravity of a planet is based on how dense the planet is, and how much of it there is. Different planets have different masses. Bigger the mass, higher the gravity.

Answer 4

If the planet has more mass, it has stronger gravity

Answer 5

Because it has more or less mass.