“Resources exist to be consumed. And consumed they will be, if not by this generation then by some future. By what right does this forgotten future seek to deny us our birthright?” -Sid Meier’s Alpha Centauri
The dream of humanity has long been to identify an inhabited world beyond Earth, to know for certain that life is not unique to our pale blue dot. If we were located a great distance away, there are observations of Earth we could make that would tell us a tremendous amount of information about our world, including about its oceans, clouds, continents, the “greening” of our world during summer, the growth and shrinkage of icecaps and even atmospheric signatures.
So why not apply that same line of thinking to search for Earth-like worlds around other sun-like stars? While direct imaging missions that would survey large numbers of stars would be very large and very expensive, the closest two sunlike stars — Alpha Centauri A and B — are only 4.37 light years away, and would need merely a 45-centimeter telescope with minimal development and launch costs.