In a recent comment, one of the members of the studio audience, anton, wrote:
I would like to "enter" a widely accepted statistic into the discussion. It would take more than 7 planet earths to sustain a US American life style for all of our planets people.
In attempting to respond to this statistic, I tried to find out more precisely what it meant. My search of the internet found that it was, indeed, widely accepted. However, I could not find anybody who used this statistic to cite a source or to offer an explanation.
Clearly, it does not mean that we need seven times as much surface area. It’s not the case that 6/7 of the people are sitting in a holding area somewhere waiting for us to find some place to put them. In fact, people in the wealthier parts of the world use up less surface area per person than poorer people. That is to say, population densities are higher in Europe and Japan than in Africa and, yes, even China.
We also have enough food for everybody. In fact, people in the wealthier parts of the world could probably improve their standard of living by eating less food than by consuming more. Our problem here is not with the amount of food we have available, but its distribution. We are also starting to have a problem with people in the developed parts of the world removing food from the tables of the starving in order to create energy that then gets consumed in activities that are far less valuable than eating.
Water is a problem. Or, more precisely, clean water is a problem. The Defense Department predicts that future wars will be fought substantially over two things: water, and energy.
As it turns out, the problem that we have with respect to clean water is, ultimately, an energy problem. The sun is already involved in created buckets full of clean water every second. There is a very well understood process for making clean water involving evaporation and condensation. We just need to make more of it in the right places – and/or allow people to move to where it is easier to provide them with clean water.
It turns out, then, that the water problem is actually another manifestation of the energy problem.
Yet, in the area of energy, we have "seven earths" of energy available to us.
Wikipedia reports that our current energy consumption is about 140,000 terawatt hours.
The Defense Department is looking into a solar power satellite system that would produce about 950,000 terawatt hours of energy per year – coincidentally, about seven times as much energy as we are currently using. (See: Space‐Based Solar Power As an Opportunity for Strategic Security (PDF: 75pp))
The idea is that, if we can provide the world with a sufficient amount of energy, then we can avoid future wars (and the future threats to national security that wars provide). Of course, the Defense Department also recognizes that there would be certain secondary benefits if this energy were owned and operated by the United States, and for the United States to have the infrastructure built into its economy for manufacturing and maintaining such a system. But those are co-incidental concerns.
The fact remains, we have seven earths of energy available – and more. Trust me, this solar power project that the Defense Department is studying is not using up all of the solar power available. Not by a long shot. Ultimately, when we talk about the amount of energy we have available, we have countless orders of magnitude of energy available that we are not even starting to use.
We have a whole sun.
It would take a great deal of effort to harvest this energy, that's true. But, then, when I argued for a future in which the rest of the world has been raised to the standard of living of the United States, I did not expect that to happen by next Tuesday.
What about other resources, such as iron?
The asteroid belt contains several different types of asteroids. One type of asteroid that we know about are iron asteroids. These asteroids were once part of a body that was large enough to undergo separation, where the iron sank into the center of a molten core and rocky materials floated to the surface. When this body was pulverized in a collision of astronomical proportions, the core formed a set of asteroids that are made up almost entirely of pure iron.
One of those asteroids is 16Psyche. Astronomical studies of this asteroid suggest that it is a huge gravel heap of iron ore – much more pure than the iron that miners harvest from the surface of the Earth. It is not a solid body. It is a gaggle of rocks and sand held together by its own gravity, making it relatively easy to grab chunks and fly away with them.
Some of its rocks can be expected to contain higher concentrations of other heavy metals – gold, platinum, and uranium.
If we mine this asteroid at the same rate at which we mined iron ore on Earth in 2004, it would take millions of years to deplete this one source of iron. It would be a foolish waste of resources to take this ore and bring it down to Earth to be refined. It would be far more efficient to put it into a furnace in space, refine it there, and even do some preliminary shaping and molding. It turns out that metals refined in space are actually much better than metals refined in a gravity environment – since gravity causes separation of heavier elements from lighter elements that we can avoid in space. Where we do want to separate elements (as a way of removing impurities), we just give the molten bucket a spin and use centrifugal force for that purpose.
All of this mining and refining would be done in space, with zero impact on any living ecosystem. A multi-million year supply of iron, mined and refined with zero environmental impact on living ecosystems, even at seven times our current rate of production.
If we do start to worry about surface area, I would like to point out that a planet is an extremely inefficient way of creating living space. The earth contains a volume of 2000 cubic kilometers of materials for each square kilometer of surface living space.
However, if we take that same amount of material and re-engineer it for greater efficiency we can get a great deal more living space out of it. We do this by creating cylinders in space and setting them to spin in order to create artificial gravity (again, using centrifugal force). We trap the atmosphere inside, and we power the whole thing using solar power from a sun that never sets and is never hidden by clouds, whose full force shines on the solar power station that creates its power.
Most of the building material need not be anything special. The largest material need on such a station would be for shielding from cosmic rays. The only requirement that this shielding must meet is that it has mass. The slag from the mining and the refining process would work well in this role, so there would be no waste product.
Using this model, we will need only about 0.002 cubic kilometers of material to create each square kilometer of living area.
With the material in the asteroid belt we can create the surface area equivalent of 50,000 earths.
Another recent study tells us that, in the outer solar system, there are perhaps a quadrillion objects orbiting the sun outside of the orbit of Neptune. (See Space.com: Discovery Hints at a Quadrillion Space Rocks Beyond Neptune.) This works out about 150,000 space rocks for every person on Earth today.
The idea that we should think in terms of planets at all is a prejudice that we need to seriously reconsider. Planets are an extremely inefficient way to support life – particularly human life. The idea that we might need seven extremely inefficient systems to support everybody at a particular standard of living carries with it a lot of assumptions that we actually should discard. Eliminating the planetary assumption, we can see that we actually have the resources of tens of thousands of earths without stepping foot out of the inner solar system – and millions of earths beyond that.
In my vision for the future, we will eventually put these resources to work.