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Dark Energy

NY Times current event in Physics.

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Dark Energy

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  1. Resetting the Clocks Muna Sultan CUIN 6397 June 27, 2013 Dr. Ramsey

  2. Polleverywhere.com Which topic do scientists know least about? Relativity B. Quantum Mechanics C. Dark Energy and Dark Matter

  3. Concept of Time-Julian Barbour • No cause-and-effect relationship • Existence from moment to moment • “heap of moments” • No order • No sequence

  4. Radical Ideas on Time- Lee Smolin • Now taken out from Physics • Structural revisions in quantum mechanics & relativity

  5. Understand Relativity and Quantum Mechanics • Relativity- Time is not absolute • Not noticed in daily lives because relative speed must be close to speed of light • Quantum mechanics- probabilistic picture of reality, cannot feel its effects because significant only in the atom • Can predict average behavior of large number of subatomic particles, but never a single atom

  6. Do not understand origin of Universe and “Dark Energy”” • Universal parameters- mass of electron & strength of nuclear force precisely calibrated • Parameters set at the origin of the universe • Dark energy- antigravity-like force pushing galaxies apart • Dark energy is also fine tuned • All parameters lie in narrow range

  7. “AnthropicPrinciple” • Many universes with varying properties and parameter • We live in one of the universes with parameters that allow life

  8. “Cosmological Natural Selection” • black holes- singularity  create new universes • Universes with right parameters have descendants; those that don’t disappear • No evidence that universes are created from centers of black holes • “Real” time is succession of parent and descendent universes

  9. “Principle of Precedence” • Repeated measurements yield the same outcomes because phenomenon has occurred in the past, not because it is subject to laws of nature

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