1 Time Domain Research in Astronomy White Paper for the 2009-2010 Decadal Survey Committee

We consider the need for a major new observatory to explore the time domain. Major areas of need include the determination of fundamental cosmological constants; the nature of gamma ray bursts; the physics and morphology of supernovae (SN Ia, SN II, impostor SN and intermediate luminosity transients); the frequency and nature of compact object binaries and mergers; the discovery of planets orbiting stars; and the probing of deep stellar interiors with asteroseismology. At the same time, a number of developments in instrumentation make possible a major push to finally cross into time domain astronomy in a statistically meaningful and multi waveband way. A major new facility capable of dedicated, large sky angle, continuous coverage on timescales of seconds to days, is needed. I