Club Troppo’s own Missing Link included this item on Tuesday:
Henry Thornton examines the hurdles to shifting to another planet and concludes wed best start making serious efforts to save the ecosystem on this one (and ignore the idiot denialists).
Strictly speaking, this is not a correct deduction, for two reasons.
Firstly, to nitpick, Thornton is talking about the costs of colonising other “nearby” solar systems, inspired by the Deakin Lecture given by Warren Canning. Naturally, those costs are vast. Crossing the gulf between solar systems is physically possible, just not very attractive. If you have to ship living people you can’t accelerate faster than 1G; and in any case you are constrained by the speed of light. The best technology we could conceivably build with a crash program would probably yield travel time measured in the centuries.
Amongst other things:
there are enormous challenges here in terms of supplying food, water and an environment in which humans can survive for perhaps several hundred years; let alone the issues of exposure to solar radiation for prolonged periods. Further, it is hard to imagine that anyone would volunteer to spend a lifetime encased in a spaceship, for the sole purpose of breeding further generations, who themselves would be subjected to a similarly sterile existence, and without any say in the matter.
Imagine a fleet of space platforms travelling at speeds in excess of what would be possible if they had to accommodate living humans; each of these platforms carrying a bank of frozen embryos and sophisticated enough to artificially analyse the environment of their particular target planet as they approach. Only then, if all of the signs are positive, these platforms would artificially birth, nurture and educate a pre determined number of the embryos – humans that would form the first generation of colonists on the new planet.
Colonists, that in order to ensure the ongoing survival of the colony, would have a huge bank of DNA material to create the plant and other life forms necessary. This is not the stuff of science fiction – work is already underway in the development of artificial wombs, most notably that of Dr. Hung-Ching Liu, at the Center for Reproductive Medicine and Infertility at Cornell University in New York; and we are perhaps only 50 years from realising this capability.
This is Dr Canning’s proposal, in short: that the alternatives are colonisation or death, and that colonisation will take the form of transporting DNA banks and embryionic humans, to be raised by artificial wombs and computers at the destination.
As it so happens, that is science fiction, being almost exactly the scenario envisaged by Arthur C Clarke in his 1986 novel Songs of Distant Earth. Such a plan is a supreme longshot in many ways, necessary for only events which would wipe out the solar system.
Secondly, this plan falls into what Isaac Asimov coined “planetary chauvinism”, the idea that only the surfaces of planets are suitable places for humans to live. As I’ve explained at Club Troppo before, O’Neill-McKendree colonies are a far more accessible solution. They allow us to colonise our own solar system without the difficulty and danger of interstellar voyages or the multi-century problems of terraforming Mars or Venus.
Planetary colonisation is not a cost-effective option in a universe where the speed of light is a hard limit to growth. It is simply too difficult and slow.
Planets also have substantial drawbacks. Energy-wise they are difficult to reach, because to move anything from one planet to another involves the energy-intensive climb out of one gravity well, the trip across intervening space, then having to climb down into a different gravity well.
There’s also the question of gravity itself: a common proposal is to terraform Mars for settlement. Leaving aside how quickly and cheaply this might be achieved, there is the question of what effect permanently living on Mars would have on residents. It’s quite possible that people born on Mars may be unable to visit Earth due to physical adaptation. We just don’t know. In any case, colonising Mars doubles the land area available for human occupation; which sounds great, except that in a single doubling of population the advantage is dissipated.
I personally expect that other solar systems will be explored, and probably exploited remotely. But such projects will have lead-times on the order of centuries and will only become cost effective after we have exhausted the resources of our own solar system out to the Oort cloud. According to some estimates this will take between 6,000 to 12,000 years with a constant doubling rate of about 30 years. That’s a longer period than civilisation to date.
Conclusion? Barring an unlikely breakthrough in physics, the human race isn’t going to go anywhere.