Isaac Newton, was an English mathematician, who discovered "The invisible force of motion." That we call "gravity". He also discovered the 3 laws of motion. Which contain: The 1st Law- Net external force, the 2nd Law- Acceleration with the body, and the 3rd law- For every reaction, has a opposite. If it weren't for that apple falling and Isaac's curious mind, I'm not so sure we would be where we are in technological or scientific advances, today.