Volker Perlick – författare

The general theory of relativity, as formulated by Albert Einstein in 1915, provided an astoundingly original perspective on the physical nature of gr- itation, showing that it could be understood as a feature of a curvature in the four-dimensional continuum of space-time. Now, some 90 years later, this extraordinary theory stands in superb agreement with observation, prov- ing a profound accord between the theory and the actual physical behavior of astronomical bodies, which sometimes attains a phenomenal precision (in one case to about one part in one hundred million million, where several d- ferent non-Newtonian e?ects, including the emission of gravitational waves, are convincingly con?rmed). Einstein’s tentative introduction, in 1917, of an additional term in his equations, speci?ed by a “cosmological constant”, - pearsnowtobeobservationallydemanded,andwiththistermincluded,there is no discrepancy known between Einstein’s theory and classical dynamical behavior, from meteors to matter distributions at the largest cosmological scales. One of Einstein’s famous theoretical predictions that light is bent in a gravitational ?eld (which had been only roughly con?rmed by Eddington’s solareclipsemeasurementsattheIslandofPrincipein1919,butwhichisnow very well established) has become an important tool in observational cosm- ogy, where gravitational lensing now provides a unique and direct means of measuring the mass of very distant objects.

The general theory of relativity, as formulated by Albert Einstein in 1915, provided an astoundingly original perspective on the physical nature of gr- itation, showing that it could be understood as a feature of a curvature in the four-dimensional continuum of space-time. Now, some 90 years later, this extraordinary theory stands in superb agreement with observation, prov- ing a profound accord between the theory and the actual physical behavior of astronomical bodies, which sometimes attains a phenomenal precision (in one case to about one part in one hundred million million, where several d- ferent non-Newtonian e?ects, including the emission of gravitational waves, are convincingly con?rmed). Einstein’s tentative introduction, in 1917, of an additional term in his equations, speci?ed by a “cosmological constant”, - pearsnowtobeobservationallydemanded,andwiththistermincluded,there is no discrepancy known between Einstein’s theory and classical dynamical behavior, from meteors to matter distributions at the largest cosmological scales. One of Einstein’s famous theoretical predictions that light is bent in a gravitational ?eld (which had been only roughly con?rmed by Eddington’s solareclipsemeasurementsattheIslandofPrincipein1919,butwhichisnow very well established) has become an important tool in observational cosm- ogy, where gravitational lensing now provides a unique and direct means of measuring the mass of very distant objects.

All kind ofinformationfrom distant celestialbodies comestous intheform of radiation. Inmost the of electromagnetic cases thisradiation propagation be can as a reasonable in described, terms of This is approximation, rays. truenot inthe but also inthe radio only ofthe electro opticalrange range Forthis the of reason laws areoffundamental magneticspectrum. optics ray for importance and astronomy, astrophysics, cosmology. to According arethe of general relativity, light light likegeodesics a rays Lorentzianmetric whichthe is described. how by spacetimegeometry This, is true as as the under the ever, only long light are rays freelypropagating influence ofthe fieldwhich is coded in the only gravitational spacetime ge If a is in an medium ometry. light ray influenced, addition, by optical (e. g. , then it will not follow ofthe by a a plasma), light like geodesic spacetime metric. It is true that for radiation the electromagnetic traveling through universe the influence ofamedium on the ofthe and usually path on ray the is small. there are several cases inwhich this influ frequency However, ence is well in inthe radio For measurable, particular very range. example, the deflection ofradio inthe field oftheSun is consider gravitational rays influenced the Solarcorona.currentand ably by Moreover, planned Doppler with microwaves in the Solar reach in the an experiments system accuracy 5 of 10 15 whichmakes it totakethe influence frequency Awlw necessary ofthe medium into account.

The general theory of relativity, as formulated by Albert Einstein in 1915, provided an astoundingly original perspective on the physical nature of gr- itation, showing that it could be understood as a feature of a curvature in the four-dimensional continuum of space-time. Now, some 90 years later, this extraordinary theory stands in superb agreement with observation, prov- ing a profound accord between the theory and the actual physical behavior of astronomical bodies, which sometimes attains a phenomenal precision (in one case to about one part in one hundred million million, where several d- ferent non-Newtonian e?ects, including the emission of gravitational waves, are convincingly con?rmed). Einstein’s tentative introduction, in 1917, of an additional term in his equations, speci?ed by a “cosmological constant”, - pearsnowtobeobservationallydemanded,andwiththistermincluded,there is no discrepancy known between Einstein’s theory and classical dynamical behavior, from meteors to matter distributions at the largest cosmological scales. One of Einstein’s famous theoretical predictions that light is bent in a gravitational ?eld (which had been only roughly con?rmed by Eddington’s solareclipsemeasurementsattheIslandofPrincipein1919,butwhichisnow very well established) has become an important tool in observational cosm- ogy, where gravitational lensing now provides a unique and direct means of measuring the mass of very distant objects.