A new NASA publication, Cosmos & Culture: Cultural Evolution in a Cosmic Context (NASA SP-4802) is available as a free 612-page 4MB PDF download. Editors Steven J. Dick and Mark L. Lupisella present a series of essays integrating concepts from philosophical, anthropological, and astrobiological disciplines to explore the interdisciplinary questions of cosmic evolution.
A couple of interesting quotes are below.
The first quote is by Howard Bloom (a member of the NSS Board of Governors) from an essay entitled “The Big Burp and the Multiplanetary Mandate”:
Evolution is shouting a message at us. Yes, evolution herself. That imperative? Get your ass off this planet. Get your asses, your burros, your donkeys, and as many of your fellow species as you can—from bacteria and plants to fish, reptiles, and mammals—off this dangerous scrap of stone and find new niches for life. Take the Grand Experiment of Cells and DNA, the 3.85-billion-year Project of Biomass, to other planets, moons, orbiting habitats, and galaxies. Give life an opportunity to thrive, to reinvent itself, to turn every old disaster, every pinwheeling galaxy, into new opportunity. Do this as the only species nature has generated that’s capable of deliberate travel beyond the atmosphere of Earth. Do it as the only species able to take on the mission of making life multiplanetary. Accept that mission—the Greening of the Universe—or you may well eliminate yourself and all the species that depend on you—from the microorganisms making folic acid and vitamin K in your gut to wheat, corn, cucumbers, chickens, cows, the yeast you cultivate to make beer, and even the bacteria you use to make cheese. What’s worse, if you fail to take life beyond the skies, the whole experiment of life—including rain-forests, whales, and endangered species—may die in some perfectly normal cosmic catastrophe.
The second quote is from an essay by Seth Shostak on “The Value of ‘L’ and the Cosmic Bottleneck” (where “L” is the average lifetime of a technological civilization):
We have seen that, if the dismal, albeit trendy, apocalyptic scenarios of war, environmental degradation, and short-term cosmic threats can be thwarted, our future might be anything from thousands to million of years. However, even with this sunnier prognosis, there is little doubt that—sooner or later—we will be obliged to move at least some of our population into space. Earth, being spherical, has the minimum surface area for its mass. Resources—both the obvious ones such as arable land, as well as the less obvious ones, such as platinum—are finite, and in many cases already scarce. So, putting aside the possibility that, by engineering our own successors or joining the “galactic club” we may introduce a major discontinuity in the story of Homo sapiens, there’s one reasonably reliable expectation we can have for our activities of the next 100 years: the expansion of habitat to the nearby, extraterrestrial realms of the solar system. This settlement of a new frontier could have a telling, and salubrious effect on the Earthly value for L.
We have visited the Moon, and our mechanical proxies have landed on Mars. Both worlds could be colonized, and in the case of Mars, made more amenable to life (Wood 2007). That this will happen is less a question of “if” than “when.” While the initial colonies will be small, historical analogs suggest that within a century they will have populations measured in the tens of thousands or more.
The carrying capacity of these nearby bodies is limited. However, the numbers of humans living in orbit could dwarf their populations. Two decades ago, Gerard O’Neill (1977) and Thomas Heppenheimer (1979) described in detail how we could build artificial habitats in space: slowly rotating aluminum cylinders, having diameters of several kilometers, that could house entire villages and towns. Their prediction was that by the 1990s, millions of Earthlings would be living in these space habitats. That hasn’t yet happened, but not because it’s technically impractical. Rather, at the moment, building such artificial cities in orbit is economically and politically impractical.
In the somewhat longer view, perhaps one to two centuries hence, we can consider colonizing the larger bodies of the asteroid belt.
While the exact time scale of these projects is subject to the vagaries of political will, one can conservatively foresee that within two centuries, at most, enough of us will be off the planet—in O’Neill colonies, on the Moon and Mars, and burrowed into the asteroids—that total annihilation of human society will be as impossible as the total annihilation of Earth’s ants. We will be dispersed, and dispersal is the ultimate insurance policy for survival. Modest colonization will inoculate us against self-destruction. It might be possible to exterminate all the individuals in one habitat, but not the entire populace of all habitats.