Future Earth Prosperity Will Depend on Resources in Space
By Mark Hopkins
THE LATE PRINCETON PHYSICS PROFESSOR GERARD O'NEILL first published his ideas concerning the construction of space settlements in a now classic Physics Today article in 1974. His ideas led to the establishment of the L5 Society, which in 1987 merged with NSI to create the present National Space Society. What has come to be known as an O'Neill space settlement consists of a large cylindrical shell several miles long and a few miles wide, which is built in space, primarily from materials found in space.
The shell is spun to create the effect of normal Earth gravity and its interior is filled with what constitutes a normal Earth atmosphere. A system of windows and external mirrors brings sunlight into the cylinder in a fashion that approximates daytime on Earth. The insides of the cylinder are molded to create a highly desirable living area complete with fields, forests, hills, streams, lakes, towns, etc. This amounts to land built in space.
The asteroids have sufficient material of roughly the right composition to build O'Neill space settlements with a combined land surface area of more than 1,000 times the land surface area of Earth. If you digest the moons of the outer planets, then the land area that could be created is increased by two orders of magnitude (a factor of 100).
Beyond Pluto there exists the Oort Cloud of comets that circle the sun in orbits which taken together comprise a large sphere. Six trillion is the current estimate of the number of these comets. They extend outward from the sun for three light-years in all directions. They have enough mass to increase our total land area estimate that can be built via O'Neill settlements by substantially more than another order of magnitude (factor of 10).
Thus there are enough material resources in the solar system (not counting the planets) to create land equal to more than one million times the land area of Earth. This is a very large number but, compared to the energy resources of the solar system, it is tiny. The sun produces more than 10 trillion times the amount of energy currently used by humanity.
Nor need it stop with the solar system. Other stars may well have similar Oort Clouds. Let's assume this is the case with the Alpha Centauri system, the center of which is 4.35 light-years from the sun. If that Oort Cloud has a radius of three light-years (gravitational considerations suggest it's modestly larger) and our Oort Cloud has a radius of three light-years, then the clouds overlap creating a star bridge between the stellar systems. Any civilization that spans our Oort Cloud also will expand into the Alpha Centauri Oort Cloud. Jumps to the Oort Clouds of other stars will likely follow. In terms of land area, it is trivial but still interesting to note, that one of the stars in the Alpha Centauri system is remarkably similar to the sun and is considered to be a good candidate to have an Earth-like planet.
Why is all of this important in a big picture sense? The average American has a per capita income that is seven times greater than that of the human race as a whole. Poverty is defined in America to be substantially above human average income. This is the human average we are making comparisons with — not poor people by human standards.
Even if we assume no further population increase and no further increase in America's per capita income, then the human economy must increase seven times in order to raise the human average to what Americans now enjoy. Where are we going to get the resources to do anything like this? In actuality, the population is increasing. American per capita income is rising and desirably so. The environment needs to be improved — not get worse. All of which makes the problem more difficult. What is the solution? The answer lies in space.