The Future of Gravitational Optics

In this speculative, millenial essay, I try to anticipate what sort of novel gravitational optics investigations might be observed, after it becomes possible to map and monitor roughly a trillion sources (of which a billion may be usefully variable) comprehensively throughout electromagnetic and other spectra over the whole sky. Existing techniques suffice to produce three dimensional maps of the dark matter distribution of the accessible universe, to explore black hole spacetimes and to magnify images of the first luminous sources, terrestrial planets and compact objects.