Here's why:
* Gravity is a force of attraction between any two objects with mass. The more massive the objects, the stronger the gravitational pull between them. The Earth has a large mass, so it exerts a strong gravitational pull on objects near its surface.
* This pull is what causes objects to fall towards the Earth. When you drop a ball, it accelerates downwards because of the Earth's gravitational pull.
* The force of gravity acts on all objects, regardless of their size or shape. That's why a feather and a bowling ball will fall at the same rate in a vacuum (where air resistance is negligible).
So, the same force that causes objects to fall towards the surface of the Earth, also causes the Moon to orbit the Earth, the planets to orbit the Sun, and the stars to clump together to form galaxies.
