Earth's gravity comes from all its mass. All its mass makes a combined gravitational pull on all the mass in your body. That's what gives you weight. And if you were on a planet with less mass than Earth, you would weigh less than you do here.
How did gravity begin?
The legend is that Newton discovered Gravity when he saw a falling apple while thinking about the forces of nature. Whatever really happened, Newton realized that some force must be acting on falling objects like apples because otherwise they would not start moving from rest.
What is gravity made by?
They proposed that gravity is actually made of quantum particles, which they called "gravitons." Anywhere there is gravity, there would be gravitons: on earth, in solar systems, and most importantly in the miniscule infant universe where quantum fluctuations of gravitons sprung up, bending pockets of this tiny space- ...