Do black holes constrain varying constants?

Black holes may not constrain varying constants

New and rather controversial observations hint that the fine structure constant α may have been smaller in the early universe, suggesting that some of the fundamental “constants” of physics may be dynamical. In a recent paper [1], Davies, Davis, and Lineweaver have argued that black hole thermodynamics favors theories in which the speed of light c decreases with time, and disfavors those in whi...

Varying Constants, Black Holes, and Quantum Gravity

Tentative observations and theoretical considerations have recently led to renewed interest in models of fundamental physics in which certain “constants” vary in time. Davies, Davis and Lineweaver [1] have argued that the laws of black hole thermodynamics disfavor models in which the fundamental electric charge e changes. I show that similar considerations severely constrain “varying speed of l...

2d Stringy Black Holes and Varying Constants

Motivated by the recent interest on models with varying constants and whether black hole physics can constrain such theories, two-dimensional charged stringy black holes are considered. We exploit the role of two-dimensional stringy black holes as toy models for exploring paradoxes which may lead to constrains on a theory. A two-dimensional charged stringy black hole is investigated in two diff...

Do Black Holes Exist?

Do Black Holes Exist?

Proof that black holes exist will likely require confirmation of the existence of event horizons. The common assumption that the mere existence of large compact masses proves the case for black holes is an unwarranted extrapolation of General Relativity into a strong-field regime where it has not been adequately tested. Neither the large compact masses of galactic nuclei nor the massive compact...