8.286 The Early Universe (Fall 2013, MIT OCW). Instructor: Professor Alan Guth. The Early Universe provides an introduction to modern cosmology. The first part of the course deals with the classical cosmology, and later part with modern particle physics and its recent impact on cosmology.
(from ocw.mit.edu)

Lecture 20 - Supernovae Ia and Vacuum Energy Density

In this lecture, the professor first talked about supernovae type Ia; summarized the age of the universe and radiation flux versus redshift; and talked about vacuum energy density.