A Measurement of the Cosmic Expansion Within our Lifetime

TL;DR

This paper discusses the potential of real-time measurements of cosmic expansion through redshift drift observations, which could confirm acceleration, challenge the cosmological constant, and revolutionize our understanding of cosmology.

Contribution

It provides a clear explanation of how redshift drift measurements can determine the nature of cosmic expansion and impact fundamental cosmological theories.

Findings

Redshift drift measurement can confirm or refute cosmic acceleration.

A zero redshift drift would eliminate the need for a cosmological constant.

Real-time cosmology could resolve longstanding cosmological problems.

Abstract

The most exciting future observation in cosmology will feature a monitoring of the cosmic expansion in real time, unlike anything that has ever been attempted before. This campaign will uncover crucial physical properties of the various constituents in the Universe, and perhaps answer a simpler question concerning whether or not the cosmic expansion is even accelerating. An unambiguous yes/no response to this query will significantly impact cosmology, of course, but also the standard model of particle physics. Here, we discuss -- in a straightforward way -- how to understand the so-called `redshift drift' sought by this campaign, and why its measurement will help us refine the standard-model parameters if the answer is `yes.' A `no' answer, on the other hand, could be more revolutionary, in the sense that it might provide a resolution of several long-standing problems and inconsistencies in our current cosmological models. An outcome of zero redshift drift, for example, would obviate the need for a cosmological constant and render inflation completely redundant.