Why gravity pull towards earth

TL;DR: The acceleration caused by Earth (i.e. its gravity) is only dependent on Earth’s mass and the distance between the center of mass of Earth and the center of mass of the thing it’s attracting. The attributes of the thing attracted have nothing to do with it. Longer explanation: Gravity as a force does not act by pulling things *down* - it is an attractive force that pulls things together. In this case, something pulling you towards the Earth is pulling you down because you’ve defined “towards the Earth” as “down”. The force of gravity depends on a few factors - namely, the masses of the object in question and the distance between objects. Technically speaking, you and I have our own gravities as well. But gravity is actually a very weak force - and at the human scale, it’s negligible enough that things don’t get attracted to us visibly. All this is packaged up nicely in an equation known as Newton’s Law of Universal Gravitation, which is often written as F = (G * M1 * M2)/(r²), where M1 and M2 are the masses of the two bodies in question, r is the distance between the center of masses of the two bodies, G is the Gravitational constant, and F is the force acting on both bodies. Now take M1 as the mass of the Earth, M2 as the Mass of your object, a as the acceleration of your object, and bring in Newton’s Second Law of motion: M2 * a = (G * M1 * M2)/(r²) Divide by M2 on either side, and you’ll find that a = (G * M1)/(r²). So the acceleration of any body on the surface of Earth with regards to the Earth is only dependent on the mass of the Earth, and the radius of the Earth. In this case, a = 9.81 = g. :) (For objects like you, which are tiny in comparison to something like Earth, using radius (Earth) for r instead of (radius (Earth) + radius (you)) is a good enough approximation).

It is law of nature gravity means the earth have some power to pull the thing down

It is law of nature

It is law of nature