What happens if two galaxies collide? The average distance between
bright galaxies is only about 20 times their size, so over the history
of the Universe (14 Billion years), we expect that most bright galaxies
will have had at least one close gravitational encounter with a
neighboring galaxy. This lecture explores what happens when two
galaxies undergo in ... Show More
Feb 2006
Lecture 28: Groups & Clusters of Galaxies
Galaxies are found in groups and clusters, and these are only the
start of a hierarchy of cosmic structures up to the largest scales
observed. This lecture introduces the properties of groups and
clusters of galaxies, superclusters (clusters of clusters), and
large scale structur ... Show More
39m 58s
Feb 2006
Lecture 27: Spirals, Ellipticals, & Irregular (Oh My!)
What are the different types of galaxies? What hints can they give
us as to the structure and evolution of galaxies? This lecture
introduces the Hubble Classification System for galaxies, and describes
the properties of each major class. This detailed overview gives us
some tanta ... Show More
40m 34s
Jun 2009
Telescopes that Rocked Our World
This year marks the 400th anniversary of Galileo’s use of the first telescope. On this week’s show, we reflect on how telescopes have shifted our perspective on how small we are in size, space, and time. We also discuss how they help astronomers discover new and interesting aspec ... Show More
56 m