As we know that in newtonian (Newtonian) physics, gravity is a force between two objects with mass. F=Gm1m2/r2, if m1 is your mass,m2 is the mass of earth or moon and r is the radius (distance between forces ) of the earth or moon or other planet. When the ratio m2/r2 increases the force of gravity increases.Now, if we take mass of Earth m2E=5.97*1024 kg and its radius is rE=6378 km…. after calculation FE=9.8m2 N .For moon, m2M=7.34*1022 kg and rM=1737.4 km and after calculation F=1.62m2 N .The pull of gravity on you on earth is greater than on moon a nutshell less gravity is due to less mass. According to Einstein gravity is the curvature of space-time created by massive objects.Greater the mass is greater the curvature more the pull.
The Earth has its own magnetic field , it acts like there is huge bar magnet buried inside,but this bar magnet is not on the earth rotational axis it is shifted by some angle.The south of the bar magnet is on the magnetic north and the south polarity is on the magnetic north(image).As opposite polarities attract the magnetic needle (north) is attracted to the south polarity in the magnetic north.That’s why the needle always points north.If you want to know “why earth has magnetic field?”go to letter E.