Modelling a suspension for an experiment to measure the speed of gravity in short distances

An experiment to measure the speed of gravitational signals in short distances has been developed with the intention to study its behavior when a medium different from air is allocated between the emitter and the detection and check if the speed of the interaction changes. The experiment is composed of three sapphire bars that vibrates, and as they vibrate its creates a tidal gravitational wave signal that interacts with another sapphire bar, this bar is monitored by a very pure microwave signal and its amplitude and phase are measured and the gravity speed is calculated, all system is cooled to a temperature of 4.2 K to increase sensitivity and kept in high vacuum. The sapphire bar needs to be suspended to avoid seismic noise and other interference. This work models the sapphire bar with the suspension, a wire that suspends the bar by its center and has its performance calculated in a finite element modelling. The final result shows that the mechanical behavior of the sapphire bar is not affected by the suspension.

Experimento Mecânico para Medir a Velocidade da Gravidade

The authors have experience with the gravitational wave detector SCHENBERG, which is a resonant mass developed by the Brazilian GRAVITON. Its spherical antenna weighs 1150 kg and is monitored by six parametric ultralow noise transducers and is connected to the external environment by a suspension system designed to attenuate local, seismic and non-seismic noise, operating at a temperature of 4 K. the recognition has acquired the idea of ​​doing an experiment to measure the speed of gravity. Using monocrystalline sapphire with very high mechanical and electrical Qs, microwave sources with ultra-low phase noise, suspensions designed by Finite Element Modeling, parametric microwave transducers, excellent noise filtering properties of resonant mass and the development of high-speed rotation machines guided the authors to design the experiment. The experiment will measure the oscillations caused by the gravitational interaction with an amplitude of the order of 0.1 am 10^-19m).

Gravitational waves

In the weak field approximation, the Einstein field equations can be solved, and lead to the prediction of gravitational waves. After showing that gravitational radiation depends on changing quadrupole moments, this chapter describes the production, propagation, and detection of gravitational waves. It includes discussions of the speed of gravity, detectors, the “chirp” waveform for a compact binary system, and the nature of astrophysical sources.