PHYSICS 20B Lecture Notes - Lecture 17: Energy Density
20 May 2018
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PHYSICS 20B - Lecture 17 - Dark Energy
*Images from Professor Cooper
●1929: Hubble observes the expansion of the Universe
Velocity
away from us
Distance to Galaxy
Rough guess: How long ago was size = 0?
Hubble’s law: dV =H0
→[1/H]d=V0 Remember: distance = velocity * time
●If the universe had always expanded at a constant rate, than the age of the Universe
would be equal to [ ]/H10
Hubble Time = ]1/H[0
●By measuring , we get a rough estimate for the age of the Universe!H0
Ball Thrown from a Planet
