Abstract

Thorne will describe gravitational wave sources below about 10 Hz (massive black holes, neutron stars, white dwarfs, and phenomena in the very early universe), and the various techniques that are being developed to search for them: space-based optical interferometry (LISA and the Big Bang Observer), pulsar timing arrays, CMB polarization, and atom interferometry. It is likely that pulsar timing arrays (at 10^-7 to 10^-9Hz) will detect waves from supermassive black holes within this decade. LISA (the Laser Interferometer Space Antenna) will likely fly in approx 2020 and see tens of thousands of sources at frequencies around 0.1 to 10^-5Hz. Atom interferometry may open up the frequency band around 0.1 to 10 Hz. CMB Polarization (at around 10^-17 Hz) may bring us our first glimpse of the inflationary era when the universe was around 10^-34 seconds old. The Big Bang Observer in the 2030s (at around 0.001 to 1 Hz) may bring us an in depth study of the big bang and also the kind of high-resolution observations of the contemporary universe that are now routinely achieved by optical, radio, and x-ray telescopes.