Goddard Space Flight Center, Greenbelt, Maryland 20771

ENGINEERING COLLOQUIUM 

Monday, April 16, 2001 / 3:30 PM, Building 3 Auditorium 

Michael E. Levi

ABSTRACT -- Supernova studies indicating cosmic acceleration -- based on observations that distant supernovae were dimmer than their redshifts would otherwise suggest -- were first presented in January 1998.  This first direct experimental evidence for an accelerating universe, interpreted as a positive value of Einstein's Cosmological Constant, can be interpreted as a new unknown force (termed "dark energy") that permeates all of space.  These results have been greatly substantiated by the current measurements of the mass density of the universe, when taken together with the anisotropy of the cosmic microwave background.  Cosmologists expected the universe's expansion to be slowing down due to the gravitational attraction between all the mass in the universe, but it now appears that there is some other energy that pervades all space, pushing it to expand.  The proposed satellite -- dubbed SNAP, for SuperNova/Acceleration Probe -- is designed to study this mysterious accelerating energy empirically.  SNAP will study thousands of distant supernovae, each with unprecedented precision, using a 2-meter telescope with a one-degree-wide field-of-view and a unique billion-pixel camera.  SNAP will use supernovae as cosmic markers of the scale of the universe over time and thus construct a history of the universe's growth.  SNAP is currently in a pre-conceptual design phase and is funded for that purpose by the DOE's Office of Science.  In this presentation, the development status, technologies, and design of the SNAP satellite will be described.

SPEAKER -- Dr. Michael Levi is a Senior Scientist at Lawrence Berkeley National Laboratory (LBNL), and Project Director for the SNAP project.  He received his Ph.D. in physics from Harvard in 1984, was a CERN scientific associate from 1984-1985, a post-doc at the Stanford Linear Accelerator Center from 1985-1987, and joined LBNL in 1987.  Dr. Levi has published over 200 scientific papers, received several awards for research, and is a Fellow of the American Physical Society.  In addition to his responsibilities on SNAP, he is group leader for the CCD Technology group at LBNL.