Black Holes or Frozen Stars? A Viable Theory of Gravity without Black Holes

TL;DR

This paper introduces a gravity theory where collapsing stars form stable frozen stars instead of black holes, matching general relativity in certain limits and challenging the necessity of horizons for black hole candidates.

Contribution

It proposes a viable alternative gravity theory that prevents horizon formation, resulting in stable frozen stars indistinguishable from black holes in observations.

Findings

Frozen stars form instead of black holes during collapse.

In the limit, the theory reproduces Einstein's equations of GR.

The theory remains physically viable and conceptually sound.

Abstract

Do observations of black hole candidates rule out alternative theories of gravity without horizon formation? This depends on the existence, viability and reasonableness of alternative theories of gravity without black holes. Here a theory of gravity without black hole horizon formation is presented. The gravitational collapse stops shortly before horizon formation and leaves a stable frozen star. In the limit $\Xi, \Upsilon\to 0$ the Einstein equations of GR are recovered, and the frozen stars become observationally indistinguishable from GR black holes. The theory therefore provides a counterexample to recent claims that observational evidence from black hole candidates "all but requires the existence of a horizon". The theory presented here shares its equations with RTG. Nonetheless, as is shown, there remain important conceptual and physical differences. In particular, some serious problems of RTG are not present in the theory proposed here. So it can be argued that the theory is a physically viable and conceptually sound alternative to GR.