The Galactic Center as a laboratory for theories of gravity and dark matter

TL;DR

The Galactic Center serves as a natural laboratory for testing gravity theories and dark matter models through astronomical observations, especially on small scales near the supermassive black hole.

Contribution

This review highlights how observations of the Galactic Center have advanced tests of General Relativity, dark matter paradigms, and alternative black hole models.

Findings

Observations have confirmed predictions of General Relativity near the supermassive black hole.

Data constrains alternative theories of gravity and dark matter.

Small-scale observations are crucial for understanding fundamental physics.

Abstract

The Galactic Center of the Milky Way, thanks to its proximity, allows to perform astronomical observations that investigate physical phenomena at the edge of astrophysics and fundamental physics. As such, it offers a unique laboratory to probe gravity, where one can not only test the basic predictions of General Relativity, but is also able to falsify theories that, over time, have been proposed to modify or extend General Relativity; to test different paradigms of dark matter; and to place constraints on putative models that have been formulated as alternatives to the standard black hole paradigm in General Relativity. In this review we provide a general overview of the history of observations of the Galactic Center, emphasizing the importance, in particular on the smallest-observable scales, that they had in opening a new avenue to improve our understanding of the underlying theory of gravity in the surrounding of a supermassive compact object.