49:45 duration 49 minutes 45 seconds
ASTR 1523 Lecture 10
50:28 duration 50 minutes 28 seconds
ASTR 1523 Lecture 9
49:56 duration 49 minutes 56 seconds
ASTR 1523 Lecture 8
52:30 duration 52 minutes 30 seconds
ASTR 1523 Lecture 6