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Why Brooklyn Is Not Expanding

Why Brooklyn Is Not Expanding. Intro Cosmology Short Course Addendum to Lecture 2 Paul Stankus, ORNL. It’s really Hubble’s fault…. Waistline. How much of this can I blame on the Hubble expansion?. 38 in. 28 in. Year. 1978. 2003. 28in  25y/10Gyr  18Å (I’ll take what I can get).

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Why Brooklyn Is Not Expanding

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  1. Why Brooklyn Is Not Expanding Intro Cosmology Short Course Addendum to Lecture 2 Paul Stankus, ORNL

  2. It’s really Hubble’s fault…. Waistline How much of this can I blame on the Hubble expansion? 38 in 28 in Year 1978 2003 28in  25y/10Gyr  18Å (I’ll take what I can get)

  3. If Earth and Moon were both in the Hubble flow: Retroreflector on the Moon Laser ranging good to ~3cm A man once asked me: “If space itself is expanding, then why isn’t the distance from the Earth to the Moon increasing?”

  4. - -   An initial value problem Assume that the Robertson-Walker metric is valid down to very small scales. How does the cosmic expansion a(t) change the relative trajectory of two particles? v v OR

  5. Velocity: Apart Acceleration: Together Velocity:ZeroAcceleration:Together Velocity:ZeroAcceleration:Apart Robertson-Walker Coordinates t a(t) c Velocity: Apart Acceleration: Apart Time A -- very small -- apparent force Robertson-Walker Coordinates t a(t) c Time

  6. OK, but how small? (Ans: damn darn small) Normal aMoon-Earth ~ dMoon-Earth /(1 month)2(up to 2p) Extra aMoon-Earth ~ dMoon-Earth (H0)2(up to 8p) dMoon-Earth/(10 Gyr)2

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