Eric Linton with Lawrence Krauss

Constraining Vacuum Energy

Distance measurements to Type Ia supernovae (SNe Ia) suggest that the expansion rate of the universe is increasing with time, contrary to previous beliefs about the evolution of the universe. One mechanism that could account for this acceleration is vacuum energy, also referred to as the cosmological constant, which would exert a large, negative pressure counteracting the deceleration effects of gravity. The uncertainty in the measurements made of supernovae at various redshifts will be examined in order to determine at which redshifts supernovae observations should be made to most efficiently place constraints on the vacuum energy. In addition, we will explore how strategies may vary depending upon how these uncertainties vary as a function of redshift, and also depending on which physical questions one wishes to probe.