WFU Physics Colloquium

TITLE: Neutron Stars, High Densities, and Nuclear Physics

SPEAKER: Professor M. Coleman Miller,

TIME: Thursday Nov. 5, 2009 at 4:00 PM

PLACE: Room 101 in Olin Physical Laboratory

The theory of general relativity has been well tested in weak gravity, but (perhaps fortunately for us) very strong gravity is out of the reach of laboratory experiments. It is therefore necessary to observe accreting neutron stars and black holes to look for some of the predicted effects of highly curved spacetime. One crucial phenomenon expected in strong gravity is that not all circular orbits are stable. The existence of an innermost stable circular orbit (ISCO) underlies much of black hole accretion theory, but clear detection of its signatures has proved difficult. I will discuss evidence from X-ray observations of some neutron stars that suggests not only that the ISCO plays a role in timing properties, but that these neutron stars are close to two solar masses, which would have important implications for physics at several times nuclear density.