NEXT STEPS IN OBSERVATIONAL COSMOLOGY

Jeremy Mould
Australian National University


IfA Colloquium March 6 2000

Cosmology is the study of the large scale structure of the Universe.
It was once called the quest for two numbers. The HST Key Project
on the extragalactic distance scale has just reported its measurement
of the first of these numbers, the Hubble Constant, to +/-10% accuracy,
and this was the subject of a colloquium last year. There is also some
consensus about the second number which measures the curvature of space.
So is cosmology solved ?

It seems more likely that we have only scratched the surface in our
understanding of the expansion of the Universe. Without touching deeper
questions of physical cosmology, such as inflation, there are some clear
near-term projects in observational cosmology. First we look at the prospects
for improving the measurement of the dimensionless quantity H_0 t_0, the
product of the Hubble Constant and the age of the Universe.

Second, we consider what can be learned about the evolution of large scale
structure. We discuss the cosmic infrared background, the importance of 
redshift surveys at earlier epochs, and the implications for the instruments 
with which we should be equipping large ground-based telescopes.