This edition: Cosmology
This lesson delves into the complex subject of cosmology, in which some of the most profound questions are asked. What shape is the universe? How did it begin? How will it end? Evidence is presented that supports the Big Bang theory, and the exciting notion of dark energy is introduced. The lesson ends with our quest for a grand unified theory—a single theory capable of describing the nature of everything in the universe, from the largest clusters of galaxies to the smallest subatomic particles.