Newton found acceleration of gravity, caused by the massive object is directly proportional to mass, m, and inversely proportional to square of distance from center of object's mass. Constant of proportionality between acceleration, mass, and distance was called Gravitational Constant of universe. Look up mass of earth and radius of earth (to be used as the distance to the center of mass) and determine that constant. Now look actual Gravitational Constant of Universe. How does the answer compare?