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Physical Society Colloquium
Mini-Beatty Lectures 2005/2006 - Part III
Robert Kirshner
Clowes
Professor of Science, Harvard University
President, American
Astronomical Society
Thursday, March 30th 2006, 19:00
Leacock Auditorium
A Blunder Undone:
Exploding Stars, Dark Energy and the Accelerating Cosmos
Friday, March 31st 2006, 15:30
Keys Auditorium, Rutherford Physics Building
Foundations of Supernova Cosmology
Observations of thermonuclear supernova explosions indicate that the
expansion of the Universe is speeding up and point to the existence of
dark energy. This talk will review the evidence that measuring the time
history and colors (the “light curve”) of a Type Ia
supernova provides a distance indicator that is good to better than 9%,
making these the best extragalactic distance indicators. I will sketch
the method by which the observed history of cosmic expansion is used to
constrain the properties of dark energy. The dark energy appears to be
consistent with the Cosmological Constant, only at much, much smaller
values than predicted by fundamental physical theory. Present and future
observational work from the ground can constrain the equation of state for
the dark energy to 10%; future space-based missions can do much better.
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