Lecture 41: Interstellar Travel and Colonization

If we ever detect life elsewhere, how will we go visit? This lecture considers the challenges of interstellar travel and colonization. The problem is one of basic physics (the enormous energy requirements of star flight) coupled with the vast, irreducible distances between the stars. I will describe various starship concepts that use reasonable extrapolations of current technologies (nuclear propulsion and solar sails), ignoring for our discussions science-fiction exotica like faster-than-light drives and wormholes. My interest is in the scientific aspects of the problem, not an exploration of speculative fiction. I then turn to interstellar colonization, and how even a relatively modest star-flight capability might allow a determined civilization to colonize the entire galaxy very rapidly. This has implications for how we might interpret the results of Drake Equation type arguments about the frequency of intelligent life in the Galaxy, and leads to the Fermi Paradox that will be the topic of the next lecture. Recorded live on 2009 Nov 25 in Room 1005 Smith Laboratory on the Columbus campus of The Ohio State University.