What is the shape and size of the Earth? This lecture traces historical
ideas about the shape of the Earth, from ancient ideas of a Flat-Earth
to Aristotle's compelling demonstrations in the 3rd century BC that the
Earth was a sphere. We then discuss two famous classical measurements
of the circumference of the Earth by Eratosthenes of Cyrene in the 3rd
ce ... Show More
Mar 2006
Lecture 44: Life, the Universe, and Everything (Life Part II)
How can we search for extraterrestrial intelligence, and what are we looking for? This second part of a 2-part lecture picks up where we left off yesterday by examining SETI, the Search for ExtraTerrestrial Intelligence, and reviews what we might look for and how. We will use thi ... Show More
45m 56s
Sep 2006
Lecture 2: Astronomical Numbers
Before we can begin our exploration of astronomy, we need to develop a
common language for notating large numbers, and introduce the basic
units of length, mass, and time that we will use throughout the quarter.
We will first re-introduce the basic metric system, explaining how t ... Show More
43m 29s