  A brief but broad survey is presented of the flows, forms and large-scale
transformations of mass-energy in the universe, spanning a range of about
twenty orders of magnitude (m_{Planck}/m_{proton}) in space, time and mass.
Forms of energy considered include electromagnetic radiation, magnetic fields,
cosmic rays, gravitational energy and gravitational radiation, baryonic matter,
dark matter, vacuum energy, and neutrinos; sources considered include vacuum
energy and cosmic expansion, fluctuations and gravitational collapse, AGN and
quasars, stars, supernovae and gamma ray bursts.
