About This Chapter
1. What is an Accretion Disk? - Definition & Theory
In this lesson, learn about accretion disks, and how and why they form in our universe. Then discover the important role they play in the discovery and study of black holes.
2. What is the Big Crunch? - Definition, Theory & Evidence
Much like how the Big Bang is a theory for the origins of our universe, the Big Crunch is one of the possible ways it might end. Learn exactly what the Big Crunch entails, and then review the evidence to see how likely it is to happen.
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