Crash Course Pods: The Universe Ep. 7: What’s Keeping the Stars Apart
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Jul 17, 2024 Astrophysicist Katie Mack and podcast host John Green discuss dark energy keeping stars apart. They explore cosmic noon, redshift, galaxy collisions, dark matter, and the universe's accelerating expansion due to dark energy. They delve into the mysteries of fundamental constants, Hubble Tension, and the poetic side of astrophysics.
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Cosmic Noon: Peak Star Formation
- Cosmic noon is the peak period when star formation and galaxy merging were most intense in the universe's adolescence.
- It's a sweet spot where gravity and expansion balanced to allow complex structures like galaxies to form.
Redshift as Cosmic Time
- Redshift measures how much the universe has expanded by stretching light's wavelength.
- It's used as a cosmic timeline because distance, age, and expansion correlate through redshift.
The Hubble Tension Problem
- The Hubble tension shows disparity in measuring the current universe expansion rate via supernovae versus the cosmic microwave background.
- This uncertainty leads to slightly different estimates of the universe's age, revealing gaps in our cosmological model.