Validity of general relativity in the strong-field regime

Determine whether Einstein’s general relativity accurately describes gravity in the strong-field regime at all scales below the Planck scale, or whether strong-field gravitational phenomena require a modified theory of gravity.

Background

The paper surveys theoretical foundations and observational breakthroughs in gravitational-wave physics, emphasizing how detections from compact-object mergers probe extreme gravitational environments. After outlining current and future detector capabilities, the author highlights that these observations enable unprecedented tests of gravity under strong-field conditions near black holes and neutron stars.

Against this backdrop, the author explicitly identifies a central unresolved question in fundamental physics: whether general relativity remains universally valid in the strong-field regime (potentially up to but excluding the Planck scale), or if modifications to gravity are needed to explain strong-field behavior. Resolving this question would clarify the theoretical framework governing the most extreme gravitational phenomena accessible through gravitational-wave astronomy.