
Is the universe infinite
Chapter 1
The cosmic horizon of our sight
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Chapter 2
The shape and geometry of space
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Chapter 3
Is there an edge to everything
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Chapter 4
The expanding cosmos and cosmic speed limits
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Chapter 5
Three ultimate fates of the universe
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YOUR GOAL
Master of Is the universe infinite
Ch 2 · The shape and geometry of space
teacher The cosmos stretches out flat! (Oh, so flat!) / Parallel lines never bend! (No, never bend!)
Fun Fact
Cosmic flatness: The Planck satellite measured the universe's curvature and found it is flat to within a margin of error of just 1%.
Glossary
curvature (noun)
The degree to which a geometric object, such as a curve or a surface, deviates from being flat. In 2013, the Planck satellite analyzed cosmic microwave background radiation to measure the universe's overall curvature.
The degree to which a geometric object, such as a curve or a surface, deviates from being flat. In 2013, the Planck satellite analyzed cosmic microwave background radiation to measure the universe's overall curvature.
Quiz
What happens to parallel light beams traveling through a closed, spherical universe?



