# Toward an internally consistent astronomical distance scale

## TL;DR

This paper reviews efforts to create a consistent astronomical distance scale, emphasizing the potential of RR Lyrae stars, Type Ia supernovae, and gravitational lensing, and discusses future prospects for improved accuracy.

## Contribution

It synthesizes current methods and proposes extending local distance calibration techniques to cosmological scales for greater consistency.

## Key findings

- Current distance measurements are largely mature and consistent.
- RR Lyrae stars are promising as standard candles for local distances.
- Future surveys and missions will significantly improve distance scale accuracy.

## Abstract

Accurate astronomical distance determination is crucial for all fields in astrophysics, from Galactic to cosmological scales. Despite, or perhaps because of, significant efforts to determine accurate distances, using a wide range of methods, tracers, and techniques, an internally consistent astronomical distance framework has not yet been established. We review current efforts to homogenize the Local Group's distance framework, with particular emphasis on the potential of RR Lyrae stars as distance indicators, and attempt to extend this in an internally consistent manner to cosmological distances. Calibration based on Type Ia supernovae and distance determinations based on gravitational lensing represent particularly promising approaches. We provide a positive outlook to improvements to the status quo expected from future surveys, missions, and facilities. Astronomical distance determination has clearly reached maturity and near-consistency.