Mapping the Cosmological Expansion

TL;DR

This paper reviews the advancements in mapping the universe's expansion, focusing on observational tools, challenges, and implications for understanding cosmic acceleration and the universe's fate.

Contribution

It provides a comprehensive overview of observational methods, challenges, and interpretations related to measuring cosmic expansion and acceleration.

Findings

Type Ia supernovae measure cosmic distances

Baryon acoustic oscillations and CMB provide angular scales

Understanding systematics is crucial for accurate mapping

Abstract

The ability to map the cosmological expansion has developed enormously, spurred by the turning point one decade ago of the discovery of cosmic acceleration. The standard model of cosmology has shifted from a matter dominated, standard gravity, decelerating expansion to the present search for the origin of acceleration in the cosmic expansion. We present a wide ranging review of the tools, challenges, and physical interpretations. The tools include direct measures of cosmic scales through Type Ia supernova luminosity distances, and angular distance scales of baryon acoustic oscillation and cosmic microwave background density perturbations, as well as indirect probes such as the effect of cosmic expansion on the growth of matter density fluctuations. Accurate mapping of the expansion requires understanding of systematic uncertainties in both the measurements and the theoretical framework, but the result will give important clues to the nature of the physics behind accelerating expansion and to the fate of the universe.