The Economics of Interstellar Travel
This week, the course will cover:
The properties of life.
The possibilities of extraterrestrial life in our solar system.
The types of stars that could have life bearing planets.
The search for extraterrestrial intelligence.
In this week's lecture, I
would like to cover a topic, The Economics of Interstellar Travel,
which is rarely, if at all, addressed but which pertains to the search for extraterrestrial
intelligence, the Fermi Paradox, i.e., “Where are they?”, and the existence of UFO's.
As described in the textbook, if there is an interstellar civilization, then it will colonize
planets in all regions of our galaxy in a few million years. In this scenario, a civilization
sends colonists to other star systems, and several hundred years later, after the
technological infrastructure is rebuilt, the colonies send out colonists of their own to
more distant stars. At reasonable starship speeds, this wave of colonization would cover
the entire galaxy on a timescale short compared to the evolution of life on earth.
To date, the SETI efforts have not detected any signals from such an interstellar
civilization. Additionally, there are no 'obvious' signs that such a civilization has ever
visited the earth. It is like visiting New York City and not seeing any people walking the
The SETI searches are neither complete nor exhaustive, so the absence of proof of
existence is not yet proof of absence. Since the surface of the earth is geologically
active, it is also easy to imagine scenarios in which the evidence of previous visits
would be destroyed. Or perhaps the interstellar visitors were just extremely tidy and
took all their trash and camping gear back home with them.
While this is an Astronomy course, the disciplines of History and Economics might
provide a more mundane answer to the question of “Where are they?”. Based on our
own history, why have large numbers of people traveled great distances to new lands?