scholarly journals ISSUE ON MEASURING THE LIGHT SPEED IN VACUUM

2021 ◽  
Vol 82 (4) ◽  
pp. 61-64
Author(s):  
Vasil Сhaban ◽  
Keyword(s):  
Gravitational Field ◽  
Differential Equations ◽  
Gravitational Lens ◽  
Electric Signal ◽  
The Sun ◽  
Speed Of Light ◽  
Light Speed ◽  
Shapiro Effect

Based on the proposed differential equations of the interaction of the electric signal with the gravitational field, the observed phenomena are known as the gravitational lens and the Shapiro effect are investigated. The deflection of a light ray in the field of the Sun is simulated. It is shown that a moving photon undergoes in the gravitational field not only a transverse action, which causes a curvature of the trajectory but also a longitudinal one, implementing the acceleration-braking processes. As a result, the instability of the speed of light in a vacuum was revealed.

scholarly journals GRAVITOMAGNETISM AND THE SPEED OF GRAVITY

2006 ◽  
Vol 15 (03) ◽  
pp. 305-320 ◽  
Author(s):  
SERGEI M. KOPEIKIN
Keyword(s):  
Gravitational Field ◽  
Lorentz Invariance ◽  
Einstein Equations ◽  
Gravitational Lens ◽  
The Sun ◽  
Gravitomagnetic Field ◽  
Relativistic Time ◽  
Speed Of Gravity ◽  
Gravitational Deflection Of Light ◽  
Gravity Probe

Experimental discovery of the gravitomagnetic fields generated by translational and/or rotational currents of matter is one of primary goals of modern gravitational physics. The rotational (intrinsic) gravitomagnetic field of the Earth is currently measured by the Gravity Probe B. The present paper makes use of a parametrized post-Newtonian (PN) expansion of the Einstein equations to demonstrate how the extrinsic gravitomagnetic field generated by the translational current of matter can be measured by observing the relativistic time delay caused by a moving gravitational lens. We prove that measuring the extrinsic gravitomagnetic field is equivalent to testing the relativistic effect of the aberration of gravity caused by the Lorentz transformation of the gravitational field. We show that the recent Jovian deflection experiment is a null-type experiment testing the Lorentz invariance of the gravitational field (aberration of gravity), thus, confirming existence of the extrinsic gravitomagnetic field associated with the orbital motion of Jupiter with accuracy 20%. We comment on physically inadequate interpretations of the Jovian deflection experiment given by a number of researchers who are not experts in modern VLBI techniques and the subtleties of JPL ephemeris. We propose to measure the aberration of gravity effect more accurately by observing the gravitational deflection of light by the Sun and processing VLBI observations in the geocentric frame with respect to which the Sun is moving with velocity ~30 km/s.

A proposal for an electrical connection between the gravitational field and light

2020 ◽  
Vol 33 (3) ◽  
pp. 271-275
Author(s):  
Michael J. Curran
Keyword(s):  
Gravitational Field ◽  
Magnetic Fields ◽  
Gravitational Waves ◽  
Building Block ◽  
Electromagnetic Waves ◽  
Direct Photon ◽  
The Sun ◽  
Speed Of Light ◽  
Electrical Connection ◽  
The Relationship

Based on well-established equations, we provide evidence of an electrical connection between the gravitational field and light. Each is modeled using the inductance‐capacitance ( <mml:math display="inline"> <mml:mrow> <mml:mi>L</mml:mi> <mml:mi>C</mml:mi> </mml:mrow> </mml:math> ) circuit as the building block. A proposed direct photon force (not a pressure and not by means of a force carrier), the relationship between the speed of light and gravity, the frequency and wavelength of gravitational waves, gravitational redshift, the trajectory of planets around the sun, and equations of plane electromagnetic waves may all be expressed with the assistance of an ideal (no resistance) <mml:math display="inline"> <mml:mrow> <mml:mi>L</mml:mi> <mml:mi>C</mml:mi> </mml:mrow> </mml:math> circuit model of light. Each begins with the Planck‐Einstein relationship. Each suggests that gravity and electromagnetism interact directly through fluctuating electrical and magnetic fields from both sources. With this perspective Einstein's concept of the warping of spacetime may not be needed to explain gravitation.

Speed of light on a rotating platform

2020 ◽  
Vol 17 (09) ◽  
pp. 2050128
Author(s):  
E. Benedetto ◽  
F. Feleppa ◽  
G. Iovane ◽  
E. Laserra
Keyword(s):  
Gravitational Field ◽  
Gravitational Force ◽  
Gravitational Effect ◽  
Electromagnetic Signal ◽  
Speed Of Light ◽  
Rotating Platform ◽  
Noninertial Frame ◽  
The Earth ◽  
Shapiro Effect ◽  
Sagnac Phase

In this paper, some analogies between the Shapiro effect in the solar gravitational field and the Sagnac phase shift have been found. Starting from Einstein equivalence principle (EEP), which states the equivalence between the gravitational force and the pseudo-force experienced by an observer in a noninertial frame of reference, we imagine an observer on a rotating platform immersed in a gravitational field. In the Shapiro effect, for example, we know that the speed of an electromagnetic signal, calculated from the Earth, is less than [Formula: see text], but, if we calculate the speed using a clock at rest in the solar gravitational field, where the photon is passing, we get that the speed of light is [Formula: see text]. Similarly, by considering the fictitious gravitational field of the rotating platform, if we look for a clock with respect to which the signal speed is [Formula: see text], we can interpret the time delay as a gravitational effect.

Tests in the solar system

2018 ◽  
Author(s):  
Nathalie Deruelle ◽  
Jean-Philippe Uzan
Keyword(s):  
Gravitational Field ◽  
Solar System ◽  
Relativistic Effects ◽  
Spherical Shape ◽  
Geodesic Equation ◽  
The Sun ◽  
Newtonian Theory ◽  
Shapiro Effect ◽  
Dimensionless Ratio ◽  
Celestial Bodies

This chapter describes observable relativistic effects in the solar system. In the solar system we can, as a first approximation, neglect the gravitational field of all the stars except the Sun. In Newtonian theory, the planet trajectories are then Keplerian ellipses. Relativistic effects are weak because the dimensionless ratio characterizing them is everywhere less than GM⊙/c² R⊙≃ 2 × 10–6, and so they can be added linearly to the Newtonian perturbations due to the other planets, the non-spherical shape of celestial bodies, and so on. The chapter first describes the gravitational field of the Sun using a Schwarzschild spacetime, before moving on to look at the geodesic equation. It also discusses the bending of light, the Shapiro effect, the perihelion, post-Keplerian geodesics, and spin in a gravitational field.

Seti Space Missions

1997 ◽  
Vol 161 ◽  
pp. 761-776 ◽  
Author(s):  
Claudio Maccone
Keyword(s):  
Electromagnetic Waves ◽  
Space Missions ◽  
Gravitational Lens ◽  
The Sun ◽  
Space Antenna ◽  
Focal Distance ◽  
Large Space ◽  
The Earth ◽  
Space Antennas ◽  
New Space

AbstractSETI from space is currently envisaged in three ways: i) by large space antennas orbiting the Earth that could be used for both VLBI and SETI (VSOP and RadioAstron missions), ii) by a radiotelescope inside the Saha far side Moon crater and an Earth-link antenna on the Mare Smythii near side plain. Such SETIMOON mission would require no astronaut work since a Tether, deployed in Moon orbit until the two antennas landed softly, would also be the cable connecting them. Alternatively, a data relay satellite orbiting the Earth-Moon Lagrangian pointL2would avoid the Earthlink antenna, iii) by a large space antenna put at the foci of the Sun gravitational lens: 1) for electromagnetic waves, the minimal focal distance is 550 Astronomical Units (AU) or 14 times beyond Pluto. One could use the huge radio magnifications of sources aligned to the Sun and spacecraft; 2) for gravitational waves and neutrinos, the focus lies between 22.45 and 29.59 AU (Uranus and Neptune orbits), with a flight time of less than 30 years. Two new space missions, of SETI interest if ET’s use neutrinos for communications, are proposed.

scholarly journals Quasi-Band-Limited Coronagraph for Extended Sources

2021 ◽  
Vol 10 (01) ◽  
pp. 2150002
Author(s):  
Igor Loutsenko ◽  
Oksana Yermolayeva
Keyword(s):  
High Resolution ◽  
High Ratio ◽  
Gravitational Lens ◽  
High Resolution Imaging ◽  
The Sun ◽  
Extended Source ◽  
Amplitude Image ◽  
Extended Sources ◽  
Resolution Imaging ◽  
Band Limited

We propose a class of graded coronagraphic “amplitude” image masks for a high throughput Lyot-type coronagraph that transmits light from an annular region around an extended source and suppresses light, with extremely high ratio, from elsewhere. The interior radius of the region is comparable with its exterior radius. The masks are designed using an idea inspired by approach due M. J. Kuchner and W. A. Traub (“band-limited” masks) and approach to optimal apodization by D. Slepian. One potential application of our masks is direct high-resolution imaging of exo-planets with the help of the Solar Gravitational Lens, where apparent radius of the “Einstein ring” image of a planet is of the order of an arc-second and is comparable with the apparent radius of the sun and solar corona.

scholarly journals Gravitational Fields and Gravitational Waves

2021 ◽  
Author(s):  
Tony Yuan
Keyword(s):  
Gravitational Field ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Doppler Effect ◽  
Gravitational Force ◽  
Laser Interferometer ◽  
Speed Of Light ◽  
Gravitational Fields ◽  
Light Waves ◽  
Research Questions

The relative velocity between objects with finite velocity affects the reaction between them. This effect is known as general Doppler effect. The Laser Interferometer Gravitational-Wave Observatory (LIGO) discovered gravitational waves and found their speed to be equal to the speed of light c. Gravitational waves are generated following a disturbance in the gravitational field; they affect the gravitational force on an object. Just as light waves are subject to the Doppler effect, so are gravitational waves. This article explores the following research questions concerning gravitational waves: What is the spatial distribution of gravitational waves? Can the speed of a gravitational wave represent the speed of the gravitational field (the speed of the action of the gravitational field upon the object)? What is the speed of the gravitational field? Do gravitational waves caused by the revolution of the Sun affect planetary precession? Can we modify Newton&rsquo;s gravitational equation through the influence of gravitational waves?

James Bradley, Sailing on the Thames

Lightspeed ◽  
2019 ◽  
pp. 49-57
Author(s):  
John C. H. Spence
Keyword(s):  
Eighteenth Century ◽  
Experimental Evidence ◽  
The Sun ◽  
Theory Of Relativity ◽  
Speed Of Light ◽  
Astronomical Observations ◽  
The Earth ◽  
Independent Estimate ◽  
The Universe ◽  
At Home

The story of the astronomical observations of James Bradley in the eighteenth century, whose measurements of the small movements of a star throughout the year provided an independent estimate of the speed of the Earth around the Sun relative to the speed of light. His work provided the first experimental evidence in support of Copernicus’s theory that the earth is in motion, and against the idea that it is stationary at the center of the universe. His simple telescope at home, his brilliant idea and perseverance, and his life’s work and influence. The importance of his result for the development of Einstein’s theory of relativity and for theories of the Aether in the following centuries.

Ole Roemer, Who Started It All

Lightspeed ◽  
2019 ◽  
pp. 18-26
Author(s):  
John C. H. Spence
Keyword(s):  
Life Story ◽  
The Sun ◽  
Speed Of Light ◽  
The Earth ◽  
At Home

The story of the first measurement of the speed of light by Ole Roemer in 1676. Galileo had discovered the moons of Jupiter with his new telescope, and proposed using observations of their eclipse every forty-two hours as a universal clock for our planet, since they could be seen from practically anywhere. This would keep track of the time at home, and so give a traveller his or her local longitude. (The King of Spain had offered a prize for longitude determination to avoid disasterous shipwrecks.) Roemer noticed that the eclipses were sometimes a little late, which he concluded was due to the time it took light to get from Saturn to Earth and the movement of the Earth between eclipses. His estimate of the time for light to travel from the Sun to Earth was quite accurate. Roemer’s remarkable life story and many other achievements are told.

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