• The Sun, planets, and other solar system objects all formed at about the same time.
  • The leading hypothesis for how they formed is called the nebular hypothesis.
  • Gravity pulls material together, it begins nuclear fusion, and a star is born.
  • The first part of the video explores the evolution of the solar system starting with the early Greeks who reasoned that since some points of light—which they called planets—moved faster than the stars, they must be closer.
  • The second part explores the history of our solar system and how it formed.
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