Original sentence: A black hole is thought to exist at the center of our galaxy
Edited sentence: ) by a cluster of neutron stars or any other candidate source of gravity.A black hole exists at the center of our milky-way galaxy.The movie from the Max Plank Institute for Astrophysics found at  shows actual observations of stellar orbits around the black hole.The shapes and sizes of the orbits are consistent with a black hole at the galactic center Sag A* and not with any other explanation yet proffered.This is proven by the concentration of mass too dense to be modeled (e