A test to the constancy of the velocity of light with our solar system

Abstract

This article is a detailed proposal of an astronomical test to be carried out within our solar system to try to detect the eventual addition of the speed of a celestial body to that of its emitted light  -that reflected of the Sun in this case. This eventuality could be determined by observing the consequent variation in its apparent position that could produce the variation of the angle of aberration, a consequence, in turn, of the variation of the velocity of its emitted light. This area is chosen, despite having here celestial bodies with lower speeds than those of the stars, and their consequent lower sensitivity in the observations, to avoid the inconvenience of the enormous interstellar distances, which could disqualify the results of the test due to the possible intervention of the phenomenon of extinction of the light wave in that distances, as we will see in the Introduction of this article. To carry out the above, we need to have celestial bodies of different radial speeds with respect to our Earth, and in this area, we find them in the satellites of the other planets in the extreme positions of their orbits; and the observation of the possible different aberrations, in the variation of the apparent separations of the satellites from their planets in those positions. The proposal also includes the observation of the transit of a satellite across the front of its planet to detect the possible appearance of this phenomenon also in this different circumstance. It will also be possible to determine if it is the relative speed between the light source and the observer the one that effectively intervenes in this phenomenon of light aberration—planetary in this case—or if it is only that of the observer—that of our Earth—that produces it, as several authors maintain. To adequately illustrate the proposed test, and the order of magnitude of the intervening parameters, a specific example is developed with Jupiter and two of its satellites: IO and METIS.