In the world of physics, Sir Isaac Newton is a big man, remembered as the scientist who devised the theory of gravity after watching an apple fall from a tree.
If you have grappled with elementary physics you will know Newton invented calculus and the Three Laws of Motion upon which all of mechanics is based.
More fundamentally, Newton's mathematical approach has become so basic to all physics that you may even think of him as the father of the 'clockwork universe.' Discovering the laws of gravitation was in itself an outstanding achievement.
Newton published the Law of Gravity in 1687, devising it to explain the mutual attraction experienced by all bodies of matter (such as an apple dropping to Earth after breaking loose from a tree).