PPT-Gravitational

Redshift in Clusters of Galaxies Marton Trencseni Eotvos University Budapest Gravitational Redshift Photon escapes from gravitational well G ains potential energy Speed cannot decrease . Millisecond . Pulsars:. Dan Stinebring. Oberlin College. CWRU – May 21, 2009. . George Greenstein. (Amherst College). Discovery of “Millisecond” Pulsars. 1982 – Arecibo Observatory – Don Backer, Sri Kulkarni, .... collapses. In . collaboration. . with. . Wen-Biao. Han, & Remo . Ruffini. . ICRANet. & . Physics. . Department. , . University. . of. . Rome. She-Sheng. . Xue. MG13, Stockholm, July 5. In 1918 Einstein published the paper ÜBER GRAVITATIONSWELLEN [1] in which, for the first time, the effect of gravitational waves was calculated, resulting in his famous “quadrupole formula” (QF). Einstein was forced to this publication due to a serious error in his 1916 paper [2], where he had developed the linear approximation (“weak- field”) scheme to solve the field equations of general relativity (GR). In analogy to electrodynamics, where accelerated charges emit electromagnetic waves, the linearized theory creates gravitational waves, popagating with the speed of light in the (background) Minkowski space-time. A major difference: Instead of a dipole moment, now a quadrupole moment is needed. Thus sources of gravitational waves are objects like a “rotating dumbbell”, e. g. realized by a binary star system. To demonstrate the physical reality of gravitational waves, consider the example system of the previous section. We will concentrate our attention on three of the test masses, one chosen arbitrarily from the plane, along with its nearest neighbors in the +x and +y directions. Imagine that we have equipped the mass at the vertex of this “L” with a lamp that can be made to emit very brief pulses of light. Imagine also that the two masses at the ends of the “L” are fitted with mirrors aimed so that they will return the flashes of light back toward the vertex mass. The Child of General Relativity. A Necessary Change. Concepts after Einstein :-. Time is not absolute. There is no ether frame. Notion of . spacetime. Concepts before Einstein :-. There is a preferred reference frame ether. some history. (based on D. . Kennefick’s. work). Historical tidbits. 1776: Laplace suggests four mechanisms that could explain secular perturbations of Moon-Earth orbit. One the explanations was a non-instantaneous propagation of gravity, affecting the binary system (abandoned because its speed would be too large to be measurable to explain the effect). . Sources and detection . Ravi . kumar. . Kopparapu. Center for Gravitational-Wave Physics (CGWP) . Gravity. Einstein’s General theory of relativity :. Gravity is a manifestation of curvature of 4- dimensional (3 space + 1 time) space-time produced by matter (metric equation ? g. Clive Tomlinson. . Einstein’s General Theory Of Relativity predicts the existence of gravitational waves (1916). Yet to be directly detected.. Gravitational Waves. . Cause a time varying curvature of space-time, propagating at the speed of light. . (& Gravitons ?). -. Vishal. . Kasliwal. Classical Electromagnetism. Vacuum. Maxwell Field Equations. Light!!. Electromagnetic waves. Quantum Electromagnetism. Hamiltonian of Quantized. Field. where. ULTRA-RELATIVISTIC COLLISIONS. Theodore Tomaras. University of Crete. Motivation. The relevance of classical gravity. A slightly simpler model – scalar radiation. The local and the non-local source. versus convective . blueshifts. , and wavelength variations across stellar disks. Dainis Dravins. – Lund . Observatory. , Sweden. www.astro.lu.se. /~. dainis. KVA. IAU Comm.30, IAU XXVIII GA Beijing, August 2012. Sections 9.1 – 9.3. Reminders. Reading quiz for Chapter 11 (Sections 1-2) due by start of class on . Tuesday.. Lab this week: Lab A7-CE – . Conservation of Energy . – due by Friday at 4 p.m.. In-class Quiz . Gravitational Waves. Prediction. General Relativity – 1915. Gravity is not the pulling force envisioned by Kepler or Newton. Space warps around massive objects. Accelerating massive objects could radiate distortions like the wake of a boat. https://www.ligo.caltech.edu/system/video_items/files/4/EinsteinsMessengerLIGO.mp4?1436490806. 2017 Nobel Prize in Physics. : Rainer Weiss - Barry C. . Barish. -Kip S. . Thorne. "for . decisive contributions to the LIGO detector and the observation of gravitational waves".