How Do We estimate a Planet’s Gravity?

We estimate a planet's gravity by measuring its mass and size. Scientists use data from spacecraft flybys or observations of the planet's effects on nearby objects, like moons or spacecraft, to calculate its mass. Then, using the planet's radius, they apply the law of gravity to determine how strong its gravitational pull is at the surface. This is why larger, denser planets like Jupiter have much stronger gravity than smaller ones like Mars.