Because-- 1) The Earth isn't quite round, it bulges at the equator. 2) Large masses such as mountain ranges cause localized differences. 3) The difference between oceans and rock. 4) Hollows and discontinuities cause slight differences.
Both mercury and mars have a gravity which is around 38% of earths. Mercury's gravity is 37.8% of earths, Mars' gravity is 37.7% of earths.
The Sun's gravity, at its surface, is about 28 times Earth's surface gravity.
Of the four inner, rocky planets, Earth is the largest and most massive. As a consequence, it has the highest surface gravity of the four inner planets. The gravity for Venus is around 90% of Earths, while for Mars and Mercury the surface gravity is around 38% of Earths.
The surface gravity of Pluto's moon Charon is around 0.278m/sec2. Compared with Earth gravity of 9.81 m/sec2, it is around 0.028g or 2.8% of earths gravity.
38% on its surface.
The moon's gravity is about 1/6th of the earth's.
The percentage of Earth's gravity on the surface of the Moon is about 16.5%.
The Gravity becomes less
the water cycle
When objects free fall near Earth's surface, they experience constant acceleration due to gravity. This means that the objects increase their velocity by the same amount each second while falling. The acceleration due to gravity near Earth's surface is approximately 9.8 m/s^2.
Of the planets in our solar system, Mars has the lowest surface gravity of around 38% of earths - over one third. This comes closest to the 25%. We then have moons and dwarf planets, but these have much lower surface gravities.
The surface gravity on Io is very low compared to Earth, due to its low mass, around 0.183g or 18.3% of the Earths pull at the surface. this is just a little more than the surface gravity on our own moon, which is about 16.5% of earths pull.