Topic

# Deflection (physics)

About: Deflection (physics) is a research topic. Over the lifetime, 3081 publications have been published within this topic receiving 33260 citations. The topic is also known as: bouncing & bounce.

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TL;DR: A measurement of the frequency shift of radio photons to and from the Cassini spacecraft as they passed near the Sun agrees with the predictions of standard general relativity with a sensitivity that approaches the level at which, theoretically, deviations are expected in some cosmological models.

Abstract: According to general relativity, photons are deflected and delayed by the curvature of space-time produced by any mass. The bending and delay are proportional to gamma + 1, where the parameter gamma is unity in general relativity but zero in the newtonian model of gravity. The quantity gamma - 1 measures the degree to which gravity is not a purely geometric effect and is affected by other fields; such fields may have strongly influenced the early Universe, but would have now weakened so as to produce tiny--but still detectable--effects. Several experiments have confirmed to an accuracy of approximately 0.1% the predictions for the deflection and delay of photons produced by the Sun. Here we report a measurement of the frequency shift of radio photons to and from the Cassini spacecraft as they passed near the Sun. Our result, gamma = 1 + (2.1 +/- 2.3) x 10(-5), agrees with the predictions of standard general relativity with a sensitivity that approaches the level at which, theoretically, deviations are expected in some cosmological models.

1,882 citations

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TL;DR: In this article, it was shown that if the law of gravitation is strictly the Newtonian law, this leads to an apparent displacement of a star close to the sun's limb amounting to 0"·87 outwards.

Abstract: 1. The purpose of the expeditions was to determine what effect, if any, is produced by a gravitational field on the path of a ray of light traversing it. Apart from possible surprises, there appeared to be three alternatives, which it was especially desired to discriminate between— (1) The path is uninfluenced by gravitation. (2) The energy or mass of light is subject to gravitation in the same way as ordinary matter. If the law of gravitation is strictly the Newtonian law, this leads to an apparent displacement of a star close to the sun’s limb amounting to 0"·87 outwards. (3) The course of a, ray of light is in accordance with Einstein’s generalised relativity theory. This leads to an apparent displacement of a star at the limb amounting to 1"·75 outwards. In either of the last two cases the displacement is inversely proportional to the distance of the star from the sun’s centre, the displacement under (3) being just double the displacement under (2).

669 citations

01 Jan 1923

TL;DR: In this paper, it was shown that if the law of gravitation is strictly the Newtonian law, this leads to an apparent displacement of a star close to the sun's limb amounting to 0"·87 outwards.

Abstract: 1. The purpose of the expeditions was to determine what effect, if any, is produced by a gravitational field on the path of a ray of light traversing it. Apart from possible surprises, there appeared to be three alternatives, which it was especially desired to discriminate between— (1) The path is uninfluenced by gravitation. (2) The energy or mass of light is subject to gravitation in the same way as ordinary matter. If the law of gravitation is strictly the Newtonian law, this leads to an apparent displacement of a star close to the sun’s limb amounting to 0"·87 outwards. (3) The course of a, ray of light is in accordance with Einstein’s generalised relativity theory. This leads to an apparent displacement of a star at the limb amounting to 1"·75 outwards. In either of the last two cases the displacement is inversely proportional to the distance of the star from the sun’s centre, the displacement under (3) being just double the displacement under (2).

595 citations

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TL;DR: In this article, the quantum-mechanical scattering amplitude can be simply related to the classical deflection function when the conditions for a semiclassical analysis of the quantum mechanics are met.

585 citations

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TL;DR: In this article, the authors model massive dark objects at centers of many galaxies as Schwarzschild black hole lenses and study gravitational lensing by them in detail, and show that the ratio of mass of a Schwarzschild lens to the differential time delay between outermost two relativistic images (both of them either on the primary or on the secondary image side) is extremely insensitive to changes in the angular source position as well as the lens-source and lens-observer distances.

Abstract: We model massive dark objects at centers of many galaxies as Schwarzschild black hole lenses and study gravitational lensing by them in detail We show that the ratio of mass of a Schwarzschild lens to the differential time delay between outermost two relativistic images (both of them either on the primary or on the secondary image side) is extremely insensitive to changes in the angular source position as well as the lens-source and lens-observer distances Therefore, this ratio can be used to obtain very accurate values for masses of black holes at centers of galaxies Similarly, angular separations between any two relativistic images are also extremely insensitive to changes in the angular source position and the lens-source distance Therefore, with the known value of mass of a black hole, angular separation between two relativistic images would give a very accurate result for the distance of the black hole Accuracies in determination of masses and distances of black holes would however depend on accuracies in measurements of differential time delays and angular separations between images Deflection angles of primary and secondary images as well as effective deflection angles of relativistic images on the secondary image side are always positive However, the effective deflection angles of relativistic images on the primary image side may be positive, zero, or negative depending on the value of angular source position and the ratio of mass of the lens to its distance We show that effective deflection angles of relativistic images play significant role in analyzing and understanding strong gravitational field lensing

350 citations