Related papers: $c$ at the belfry
The measurement of the deflection of starlight during a total solar eclipse on May 29, 1919 was the first verification of general relativity by an external team of scientists, brought Einstein and his theory to the attention of the general…
According to the theory of ether light propagates with constant speed c with respect to the absolute reference frame and with respect to any other reference frame the speed of light is covariant. According to the theory of special…
In July 5th 2014 an occultation of Mars by the Moon was visible in South America. Citizen scientists and professional astronomers in Colombia, Venezuela and Chile performed a set of simple observations of the phenomenon aimed to measure the…
In this work we show that the null result of the Michelson-Morley experiment in vacuum is deeply connected with the notion of time. It can be deduced without any mathematics only from the assumption that all good clocks can be used to…
Understanding convection in red supergiants and the mechanisms that trigger the mass loss from these evolved stars are the general goals of most observations of Betelgeuse and its inner circumstellar environment. Linear spectropolarimetry…
Einstein observers in flat space-time are inertial observers which use light to synchronize their clocks. For such observers, speed of light is a constant by construction. However, one can use super-translations to change coordinates from…
We propose to study of the light speed isotropy and Lorentz invariance at Jefferson Laboratory by means of the measurements of the Compton Edge using of the Hall A/C existing experimental setup. Methodologically the same experiment has…
The Michelson-Morley experiment was designed to detect the relative motion of the Earth with respect to a preferred reference frame, the ether, by measuring the fringe shifts in an optical interferometer. These shifts, that should have been…
The OPERA experiment reported recently a puzzling result. The time of flight of a neutrino beam between the CERN and the Gran Sasso Laboratory has been measured to be slightly shorter than expected. More precisely, an early arrival time of…
Einstein's theory of relativity establishes the speed of light in vacuum, c, as a fundamental constant. However, the speed of light pulses can be altered significantly in dispersive materials. While significant control can be exerted over…
In 1919, Eddington and Dyson led two famous expeditions to measure the bending of light during a total solar eclipse. The results of this effort led to the first experimental confirmation of Einstein's General Relativity and contributed to…
From an extended relativistic dynamics for a particle moving in a cosmic background field with temperature T, we aim to obtain the speed of light with an explicit dependence on the background temperature of the universe. Although finding…
At the end of the 19th century light was regarded as an electromagnetic wave propagating in a material medium called ether. The speed c appearing in Maxwell's wave equations was the speed of light with respect to the ether. Therefore,…
We have realized that under Lorentz transformations the tick number of a moving common clock remains unchanged, that is, the hand of the clock never runs slow, but the time interval between its two consecutive ticks contracts, so the…
High precision tests of the light speed constancy for all observers as of empirical basis of the Special Relativity have continuously been among the goals of advanced experimental studies. Based on the Compton Edge method proposed by us…
The Pierre Auger Observatory has a unique potential to search for ultra-high energy photons (above ~1 EeV). First experimental limits on photons were obtained during construction of the southern part of the Observatory. Remarkably, already…
EUSO-Balloon is a pathfinder mission for the Extreme Universe Space Observatory onboard the Japanese Experiment Module (JEM-EUSO). It was launched on the moonless night of the 25$^{th}$ of August 2014 from Timmins, Canada. The flight ended…
In the light of recent experimental and theoretical data, we go back to the studies tackled in previous publications [1] and develop some of their consequences. Some of their main aspects will be studied in further detail. Yet this text…
The refraction of a light ray by a homogeneous, isotropic and non-dispersive transparent material half-space in uniform rectilinear motion is investigated theoretically. The approach is an amalgamation of the original Fermat's principle and…
The gravitational fields of astrophysical bodies bend the light around them, creating multiple paths along which light from a distant source can arrive at Earth. Measuring the difference in photon arrival time along these different paths…