Next Contents

1. INTRODUCTION

Understanding the global history of the Universe is a fundamental goal of cosmology. One of the conceptually simplest tests in the repertoire of the cosmologist is observing how a standard candle dims as a function of redshift. The nearby Universe provides the current rate of expansion, and with more distant objects it is possible to start seeing the varied effects of cosmic curvature and the Universe's expansion history (usually expressed as the rate of acceleration/deceleration). Over the past several decades a paradigm for understanding the global properties of the Universe has emerged based on General Relativity with the assumption of a homogeneous and isotropic Universe. The relevant constants in this model are the Hubble constant (or current rate of cosmic expansion), the relative fractions of species of matter that contribute to the energy density of the Universe, and these species' equation of state.

Early luminosity distance investigations used the brightest objects available for measuring distance - bright galaxies [3, 39], but these efforts were hampered by the impreciseness of the distance indicators and the changing properties of the distance indicators as a function of look back time. Although many other methods for measuring the global curvature and cosmic deceleration exist (see, e.g., [66]), supernovae (SNe) have emerged as one of the preeminent distance methods due to their significant intrinsic brightness (which allows them to be observable in the distant Universe), ubiquity (they are visible in both the nearby and distant Universe), and their precision (type Ia SNe provide distances that have a precision of approximately 8%).

Next Contents