Neptune has a lot more mass than Earth has. However, it is also much larger than Earth. Neptune doesn't have a lot of mass for its size. So, despite its mass, Neptune's gravity is not very strong. Also, the farther you move from the center of a planet, the more its gravity decreases. Earth's surface is about 3,963 miles (6738 km) from its center. Neptune's gravity is measured from the top of its atmosphere. The top of its atmosphere is about 15,400 miles (24,800 km) from its center. So, Neptune's gravitational pull is just 12 percent greater than Earth's.
