Measuring spacetime: from big bang to black holes

TL;DR

This paper reviews observational constraints on spacetime, highlighting how phenomena like dark matter, dark energy, and gravity are tested through recent measurements across various cosmic scales, revealing a universe consistent with current cosmological models.

Contribution

It synthesizes recent observational data to evaluate the properties of spacetime and tests underlying physics assumptions in cosmology.

Findings

Universe is flat and infinite

Contains about 30% cold dark matter and 65% dark energy

Supports existence of multiple black hole populations

Abstract

Nerd abstract: Observational constraints on spacetime are reviewed, focusing on how the underlying physics (dark matter, dark energy, gravity) can be tested rather than assumed. Popular abstract: Space is not a boring static stage on which events unfold over time, but a dynamic entity with curvature, fluctuations and a rich life of its own which is a booming area of study. Spectacular new measurements of the cosmic microwave background, gravitational lensing, type Ia supernovae, large-scale structure, spectra of the Lyman alpha forest, stellar dynamics and x-ray binaries are probing the properties of spacetime over 22 orders of magnitude in scale. Current measurements are consistent with an infinite flat everlasting Universe containing about 30% cold dark matter, 65% dark energy and at least two distinct populations of black holes.