Ptolemy believed that the Earth was the centeer of the Universe. He believed that ll of the planets moved on an epicycle around the Earth. Ptolemy made some changes to his theory however, he believed that the Earth was not quite on the middle of the planet's epecycle, that it was off to the side a bit.
Aristotle believed that all bodies in the universe centered on the Earth. He believed that the Earth, the Sun, and the moon were all on their on spheres and the stars were on larger spheres surrounding them. He beleived that all things move to the center of the Earth, unless there is a force applied to the objecct.
NewtonNewton beleived that every mass in the Universe is attracted every other mass that is directly proportional to the product of their masses and inversly proportional to the square of the distance between them.
CavendishCavendish was the first man to find the accurate values for the gravitational constant. He came about these numbers as he did an expirement with a torsion balance,
EintseinEinstein believed very differently for Newton. He believed that gravity wasn't a force at all, rather just a distortion in the shape of space-time.