Transcription: In this clip, I want to review what you've learned by talking about some of the past's greatest scientists. Let's start with Ptolemy. He lived about a hundred years after Christ's birth, and as you should recall, he developed a view for what our solar system looked like. In his view, called the Ptolemaic system, the Earth sat at the center of the solar system and the planets and the sun orbited around the Earth. Even though we now know that this view of the solar system is wrong, it was a great scientific achievement for its time and it laid the groundwork for other scientific advances. For ex ...
(.mp4)