A theoretical analysis suggests that certain rotating black holes might be sensitive probes of quantum gravity.

Quantum gravity refers to a group of theories—string theory, for example—that aims to reconcile the microscopic world of quantum physics with the macroscopic world of general relativity. Many experimental tests of quantum gravity have been proposed, but the relevant effects might be too tiny to detect. Now theoretical work by Grant Remmen at the University of California, Santa Barbara, and his colleagues shows that celestial objects called extremal Kerr black holes are highly sensitive to quantum gravity. Precise observations of these bodies could therefore reveal evidence of new physics.

A Kerr black hole is a rotating, electrically neutral black hole. It is said to be extremal if it has the highest possible angular momentum that is compatible with its mass. Extremal Kerr black holes have yet to be detected, but many theories predict their existence.

The researchers say that the next step is to hunt for extremal Kerr black holes and to try to detect these curvature singularities through their effect on infalling matter.