linear force law: back to newton? ofer lahav university college london
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Linear Force Law:Back to Newton?
Ofer Lahav University College London
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Present: Dark Energy or Modified Gravity?
Abate & OL, arXiv:0805.3160
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From low-z SN Ia peculiar velocities
LCDM
DGP
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Future: Dark Energy Surveys (2010-2020)
one of five DES lensesCTIO 4m: the DES platform
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“Dark Energy”: 10, 90 or 320 years old?
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Past: back to Newton’s Principia?Weak field limit of GR:F = -GM/r2 + /3 r
X *
Lucy Calder & OLA&G Feb 08 issuehttp://www.star.ucl.ac.uk/~lahav/CLrev.pdf (revised)
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Newton, Principa (1687, Book I, Proposition 77, Theorem 37)
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Forces inside and outside a spherical shell
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CL 08
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The Mach connection
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Newton
Einstein
Can we infer ?!
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Open Questions
• Should be Newton (& Hooke) be credited for the Lambda-term (linear force)?
• Why didn’t Newton consider superposition of the inverse
square and linear laws?
• Was Einstein aware of the linear force in Principia?
• Does the Machian connection between and the total mass of the universe hold a clue for the origin of `Dark Energy’?