Map of life expectancy at birth from Global Education Project.

Monday, January 14, 2008

Please forgive my absence . . .

I'm sure my 4 1/2 readers have already figured out that I've been a bit scarce around Blogostan lately, and it's probably not a mystery why. This is my 1,211th post on Stayin' Alive -- and I've posted a fair bit elsewhere as well. On the one hand, it doesn't feel right to recycle, although truth be told there probably are quite a few posts I made earlier that I'd like folks to read again. On the other hand, I'm finding current events dispiriting rather than inspiring lately. The whole presidential primary campaign, which is the obsession of not only the corporate media but the liberal blogosphere as well, is repulsive and ridiculous as far as I'm concerned. I just want it to be over. It certainly is not an exercise in meangingful civic engagement and it makes a mockery of democracy -- that includes both parties by the way.

So, I've been blowing smoke about matters that tend to concern professors. They interest me as well but haven't gotten much of a rise out of the masses. So let me take a break from that project and think about some odds and ends.

I've always been a science fiction fan, particularly as a youth but I still read the best of the genre from time to time. Those galactic civilizations depend on faster than light space ships or farcaster portals or some such device, but a far as we know right now all of that is impossible. And yes, it is possible for things to be impossible. The universe has structure and that imposes limitations.

Interstellar travel is absolutely possible, in fact it isn't even difficult. We could mount a robotic expedition to a nearby star using current technology, that could send back information about whatever it finds there. It is even quite plausible that if civilization doesn't collapse and current trends in scientific and technological development continue, we could even send some frozen embryos, artificial wombs and robot nannies and establish a colony -- if there was a habitable place for it.

Alas, there is a very good reason why nobody is proposing such an endeavor right now, and that is the dimension of time. We are talking about sending a probe into the far future -- and I mean thousands of years. Lots of thousands. To give you an idea, the Voyager 1 spacecraft, which has already left the solar system, is traveling at about 540 million km/year. One light year is about 9.5 trillion kilometers. So, according to my crude calculations, if we concentrated on acclerating a probe to the maximum possible velocity, we ought to be able to get to above a billion km/year, which means we could cover a light year in less than 10,000 years, and get to the nearest star system in about 40,000 years or so.

With methods far superior to the pathetic chemical rockets we use today, we could probably cut that down quite a bit, but of course you would then have the problem of decelerating on the other end. Let's take an optimistic view and say you could travel between stars in 5,000 years. To an extremely long-lived species, or a species capable of taking a very long view, this would not be a problem. Five thousand years is an eyeblink in geological time, and little more than an instant in cosmic time. If a civilization had millions of years to develop, it could spread throughout a large region of the galaxy.

But, as far as we can tell, this hasn't happened. If they are out there, where are they? The most likely conclusion, to my mind, is that there just aren't any intelligent species with such immense life spans that investing in interestellar travel makes any sense. And the reason for that is a very basic fact about life.

Life cannot exist without death. Without death, there can be no evolution. A species that lives too long is going to lose the game of life, because it won't get out of the way of its offspring and more rapidly evolving species will soon eat it for lunch. That doesn't necessarily mean the shorter the better. Bacteria can evolve much faster than we can but they sacrifice the chance for complexity, and definitely for intelligence. So there is a balance.

As an intelligent social species, we need fairly long lives in order to realize the advantages evolution has given us. We need to be able to learn, to acquire knowledge and develop skills, and put those acquired assets to use in making discoveries and solving problems. The amount that we can stuff into our heads gets to the critical mass that can support maximum creativity in a little more than 20 years, for most of us, and most people can sustain a creative life for 50 years or so, and then we're done and we need to get out of the way. So our life span is about right for our ecological niche.

I suspect that is more or less true for the Zorg of Planet Bleflspk and the Vortans of Planet Frbmlr as well. Hence, no intelligent species that lives for 5,000 years, and hence no galactic civilization. It just doesn't make sense to be investing in a project that's going to come to fruition only after hundreds of generations. Very disappointing, to be sure, but why do I go through this exercise anyway? It's to point out that scientific understanding of the big questions of cosmology and biology has fundamental importance for the big questions of meaning as well. Religion tries to explain death by reference to God, but we don't need God to explain death, or for that matter to make sense and meaning out of our mortal lives, even if we don't necessarily like the answers.

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