Influence Of Cosmological Expansion Research Articles

The Adventures of the Rocketeer: Accelerated Motion Under the Influence of Expanding Space

AbstractIt is well known that interstellar travel is bounded by the finite speed of light, but on very large scales any rocketeer would also need to consider the influence of cosmological expansion on their journey. This paper examines accelerated journeys within the framework of Friedmann–Lemaître–Robertson–Walker universes, illustrating how the duration of a fixed acceleration sharply divides exploration over interstellar and intergalactic distances. Furthermore, we show how the universal expansion increases the difficulty of intergalactic navigation, with small uncertainties in cosmological parameters resulting in significantly large deviations. This paper also shows that, contrary to simplistic ideas, the motion of any rocketeer is indistinguishable from Newtonian gravity if the acceleration is kept small.

Effect of Hubble parameter on the orbit of light ray and radar echo delay in Robertson-McVittie spacetime

In this paper, the effect of Hubble parameter on the propagation of electromagnetic wave in Robertson-McVittie spacetime is discussed by using the post-Newtonian approximation method. To the bending test of light ray, the deflection angle caused by Hubble parameter H0 is calculated to its maximum amendatory term. Besides, the effects of finite distances of light source and receiver (d1 and d2 ) on deflection angle are also considered in this work. To the radar echo delay test, the maximum amendatory term to the formulae, induced by Hubble parameter, is given. The paper focuss on the study of influence of cosmological expansion on the propagation of electromagnetic wave. The work can be checked in the current high-precision gravity experiments in space and provides a theoretical basis for these experiments.