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Space Forum / Astronomy / May 2005Astrophysical Observations: Lensing and Eclipsing Einstein's Theories
I found the following that might be of general interest, particularly given the large number of alternative gravity hypotheses posted here, often by people who I fear do not understand GR. ------------------------------ Paper: astro-ph/0503315 Date: Tue, 15 Mar 2005 13:11:50 GMT (177kb) Title: Astrophysical Observations: Lensing and Eclipsing Einstein's Theories Authors: Charles L. Bennett Journal-ref: Science, vol. 307, pages 879 - 884 (11 February 2005) Albert Einstein postulated the equivalence of energy and mass, developed the theory of special relativity, explained the photoelectric effect, and described Brownian motion in five papers, all published in 1905, 100 years ago. With these papers, Einstein provided the framework for understanding modern astrophysical phenomena. Conversely, astrophysical observations provide one of the most effective means for testing Einstein's theories. Here, I review astrophysical advances precipitated by Einstein's insights, including gravitational redshifts, gravitational lensing, gravitational waves, the Lense-Thirring effect, and modern cosmology. A complete understanding of cosmology, from the earliest moments to the ultimate fate of the universe, will require developments in physics beyond Einstein, to a unified theory of gravity and quantum physics. \\ ( http://arXiv.org/abs/astro-ph/0503315 , 177kb)  SignatureLt. Lazio, HTML police | e-mail: jlazio@patriot.net No means no, stop rape. | http://patriot.net/%7Ejlazio/ sci.astro FAQ at http://sciastro.astronomy.net/sci.astro.html >I found the following that might be of general interest, particularly >given the large number of alternative gravity hypotheses posted here, [quoted text clipped - 23 lines] > >\\ ( http://arXiv.org/abs/astro-ph/0503315 , 177kb) Bennett's paper has a crude treatment of redshift in a strong gravitational field. He says regarding redshift: L/L0 = sqrt(1 - 2MG/c^2r) (with L representing the reduced lambda). He concludes that L would become zero at the horizon radius. But with constant c, wouldn't frequency go to infinity (which would imply infinite energy)? He does not cite a source. Any comments? John Polasek http://www.dualspace.net >>>>> "JCP" == John C Polasek <jpolasek@cfl.rr.com> writes: JCP> On 16 May 2005 10:41:18 -0400, Joseph Lazio JCP> <jlazio@adams.patriot.net> wrote: >> I found the following that might be of general interest, >> particularly given the large number of alternative gravity [quoted text clipped - 9 lines] >> [...] >> \\ ( http://arXiv.org/abs/astro-ph/0503315 , 177kb) JCP> Bennett's paper has a crude treatment of redshift in a strong JCP> gravitational field. He says regarding redshift: L/L0 = sqrt(1 - JCP> 2MG/c^2r) (with L representing the reduced lambda). He concludes JCP> that L would become zero at the horizon radius. But with constant JCP> c, wouldn't frequency go to infinity (which would imply infinite JCP> energy)? He does not cite a source. Any comments? Yeah, bad editing or proofreading. The gravitational redshift is zero at the horizon and goes to infinity for a distant observer. This means that the change in wavelength for an emitted photon is zero at the horizon and becomes infinite for a distant observer. SignatureLt. Lazio, HTML police | e-mail: jlazio@patriot.net No means no, stop rape. | http://patriot.net/%7Ejlazio/ sci.astro FAQ at http://sciastro.astronomy.net/sci.astro.html >I found the following that might be of general interest, particularly >given the large number of alternative gravity hypotheses posted here, [quoted text clipped - 23 lines] > >\\ ( http://arXiv.org/abs/astro-ph/0503315 , 177kb) Bennett's paper has a crude treatment of redshift in a strong gravitational field. He says regarding redshift: L/L0 = sqrt(1 - 2MG/c^2r) (with L representing the reduced lambda). He concludes that L would become zero at the horizon radius. But with constant c, wouldn't frequency go to infinity (which would imply infinite energy)? He does not cite a source. Any comments? John Polasek http://www.dualspace.net |
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