Gravity is the weakest of the four fundamental forces, and as such has only been carefully tested in weak fields, such as near the earth or in our solar system. All such tests have been consistent with the expectation that Einstein’s theory of general relativity describes gravity, at least so far. Strong-gravity astrophysical systems, such as black holes and neutron stars, open up the possibility of testing gravity more stringently and seeing whether Einstein’s relativity remains our best description of gravity, or whether something more exotic is needed to describe these objects. Strong-gravity objects are also the engines for some of the energetic processes in our universe; studying them gives us insight into the dynamics of these important astrophysical processes.
MKI researchers are leading several efforts to use upcoming astronomical observations to study strong-gravity objects. Gravitational waves are generated by the formation and dynamics of black holes and neutron stars. Scott Hughes’ research group is pursuing several projects to model the gravitational waves generated by such compact objects in binary systems, to understand how to use them to test the nature of gravity, and to use them as probes of astronomy. The LIGO observatory leads the worldwide efforts to directly measure gravitational waves. We expect that coming data from the advanced LIGO detectors, in concert with theoretical modeling of the waves that come from strong-gravity sources, will be a new and powerful probe of strong gravity and strong gravity systems.