HST and 'dark matter' |
HST and 'dark matter' |
Guest_PhilCo126_* |
May 11 2007, 05:13 PM
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#1
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Guests |
ASA Updates Plans for Hubble 'Ring Of Dark Matter' Briefing
GREENBELT, Md. - NASA will hold a media teleconference at 1 p.m. EDT on May 15 to discuss the strongest evidence to date that dark matter exists. This evidence was found in a ghostly ring of dark matter in the cluster CL0024+17, discovered using NASA's Hubble Space Telescope. The ring is the first detection of dark matter with a unique structure different from the distribution of both the galaxies and the hot gas in the cluster. The discovery will be featured in the June 20 issue of the Astrophysical Journal. |
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Sep 14 2011, 12:56 AM
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#2
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Member Group: Members Posts: 723 Joined: 13-June 04 Member No.: 82 |
This paper just came out on arXiv, in response to the paper linked to in post #41
On entropic gravity: the entropy postulate, entropy content of screens and relation to quantum mechanics We consider the controversial hypothesis that gravity is an entropic force that has its origin in the thermodynamics of holographic screens. Several key aspects of entropic gravity are discussed. In particular, we revisit and elaborate on our criticism of the recent claim that entropic gravity fails to explain observations involving gravitationally-bound quantum states of neutrons in the GRANIT experiment and gravitationally induced quantum interference. We argue that the analysis leading to this claim is troubled by a misinterpretation concerning the relation between the microstates of a holographic screen and the state of a particle in the emergent space, engendering inconsistencies. A point of view that could resolve the inconsistencies is presented. We expound the general idea of the aforementioned critical analysis of entropic gravity in such a consistent setting. This enables us to clarify the problem and to identify a premise whose validity will decide the faith of the criticism against entropic gravity. It is argued that in order to reach a sensible conclusion we need more detailed knowledge on entropic gravity. These arguments are relevant to any theory of emergent space, where the entropy of the microscopic system depends on the distribution of matter in the emergent space. |
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Lo-Fi Version | Time is now: 24th September 2024 - 04:52 AM |
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