The Restless Universe (Palomar Transient Factory) S. R. Kulkarni, Principal Investigator, Palomar Transient Factory, Director, Caltech Optical Observatories, Caltech

Cosmic explosions were first noted nearly two thousand years ago. However, secure recognition and study began only a hundred years ago. What was once termed as Stella Nova (new stars) are now divided into two major families, novae and supernovae (with real distinct classes in each). Equally the variable stars have a rich phenomenology. Together, supernovae and variable stars have contributed richly to key problems in modern astrophysics: distances to galaxies, cosmography and build up of elements in the Universe. The Palomar Transient Factory (PTF), an innovative 2-telescope system, was designed to explicitly to chart the transient sky with a particular focus on events which lie in the nova-supernova gap. PTF is now finding an extragalactic transient every 20 minutes and a Galactic (strong) variable every 10 minutes. The results so far: identification of an emerging class of ultra-luminous supernovae, the earliest discovery of a Ia supernovae, discovery luminous red novae, the most comprehensive UV spectroscopy of Ia supernovae, discovery low energy budget supernovae, clarification of sub-classes of core collapse and thermo-nuclear explosions, mapping of the systematics of core collapse supernovae, identification of a trove of eclipsing binaries and the curious AM CVns.