Real-time Cosmology

TL;DR

Real-time cosmology explores measuring the universe's dynamic changes through advanced astrometric and spectroscopic techniques, aiming to test cosmic expansion, anisotropy, and gravitational effects with upcoming experiments.

Contribution

This paper reviews the theoretical and observational developments in real-time cosmology, highlighting new methods to measure cosmic dynamics and potential constraints from future experiments.

Findings

Redshift drift measurements can trace cosmic expansion.

Angular separation shifts can detect large-scale anisotropy.

Future experiments like CODEX, GAIA, and PLANCK will enhance observational capabilities.

Abstract

In recent years the possibility of measuring the temporal change of radial and transverse position of sources in the sky in real time have become conceivable thanks to the thoroughly improved technique applied to new astrometric and spectroscopic experiments, leading to the research domain we call Real-time cosmology. We review for the first time great part of the work done in this field, analysing both the theoretical framework and some endeavor to foresee the observational strategies and their capability to constrain models. We firstly focus on real time measurements of the overall redshift drift and angular separation shift in distant source, able to trace background cosmic expansion and large scale anisotropy, respectively. We then examine the possibility of employing the same kind of observations to probe peculiar and proper acceleration in clustered systems and therefore the gravitational potential. The last two sections are devoted to the short time future change of the cosmic microwave background, as well as to the temporal shift of the temperature anisotropy power spectrum and maps. We conclude revisiting in this context the effort made to forecast the power of upcoming experiments like CODEX, GAIA and PLANCK in providing these new observational tools.