Fri03Mar20174:00 pmLewis Hall 101
Colloquium: Can a Black Hole Have Hair?
Departamento de Física
Universidade de Aveiro — Portugal
Can a Black Hole Have Hair?
Black holes are one of the most fascinanting predictions of Einstein's theory of General Relativity. In their most paradigmatic guise, they are also the simplest objects in the Universe, made solely of space and time. Moreover, powerful mathematical theorems, known as uniqueness theorems, show that the way space and time can curve into a black hole is quite restricted, and these objects are only described by two parameters: their total mass and angular momentum. John Wheeler famously coined this simplicity into the mantra "Black Holes have no hair". But underlying this statement there is an unproved belief known as the "no-hair conjecture".
I will start by discussing observational evidence for the existence of black holes in the universe. Then, I will explain why the existence of some simple types of matter, even if Einstein's theory holds, could challenge the no-hair conjecture and produce "hairy" black holes. Finally, I will discuss how ongoing and forthcoming electromagnetic and gravitational waves observations could test the existence of black hole "hair" of this sort.