Status of Cosmology

TL;DR

This paper reviews the current status of cosmological parameters, highlighting the evidence supporting specific values for the universe's age, expansion rate, matter density, and cosmological constant, based on recent observations.

Contribution

It summarizes the latest observational constraints on key cosmological parameters, providing an overview of the current understanding of the universe's composition and expansion.

Findings

Age of the universe approximately 13 billion years

Hubble parameter around 0.65

Matter density about 0.3 and cosmological constant about 0.7

Abstract

The cosmological parameters that I will emphasize are the Hubble parameter $H_0 \equiv 100 h$ km s$^{-1}$ Mpc$^{-1}$, the age of the universe $t_0$, the average matter density $\Omega_m$, the baryonic matter density $\Omega_b$, the neutrino density $\Omega_\nu$, and the cosmological constant $\Omega_\Lambda$. The evidence currently favors $t_0 \approx 13$ Gyr, $h \approx 0.65$, $\Omega_m \approx 0.3$, $\Omega_\Lambda \approx 0.7$.