- 
  
  Believed that the earth was the center of the universe. Predicted movements of the planets.
- 
  
  Made a model of the solar system with the Earth revolving around the sun.
- 
  
  Believed the earth was the center of the universe.
- 
  
  Devised three laws that govern planetary motion.
- 
  
  Formulated the basic laws of motion that are the basis of mechanics.
- 
  
  Suggested that the laws of physics are the same throughout the universe, that space and time are linked in an entity known as space-time, which is distorted by gravity and that the speed of light in a vacuum is constant.