Newton's Universal Law of Gravitation

      Many people don't think of gravity when they’re walking along the sidewalk, but it's there. It's all around. It's what makes the world go round, literally. The man who dreamed up this idea was Sir Isaac Newton. In 1687, he published his book, Philosophiae Naturalis Principia Mathematica, detailing this universal force based on the distance between objects and their masses. The equation for this force, as Newton had thought up, is as follows:

Where m1 and m2 are the masses of the objects, r is the separation between the objects, and G is the gravitational constant, a proportionality constant thought to be the same at every point in the universe, since gravity is universal, as far as we know.
      This equation has been put to the test numerous times by Isaac himself, and others, and continues to shine through over three centuries of calculations. This idea and equation of gravity has become very important to the world even today. It has helped space travel in general: without this, we wouldn't have ever gone to space. And those satellites that power wireless communication, can't work without this equation. Astronomy would not would not be where it is today without Newton's idea of gravity. All projectile motion is mainly based on gravity, so this idea helps us calculate trajectories in war, and actually getting from the Earth into space. In these ways and more, Newton's ideas have helped to power the technological age we live in today. Newton's ideas have changed the world we live in forever.