Monday 16 April 2007

Pic of the day: It is 2007, and as expected we have been to many strange and wonderful words and met many strange and wonderful creatures there. But unlike what I thought back in the 60es, those worlds were all of our own imagination. The real other worlds out there just get the occasional mention in popular science magazines and such.

Exoplanets

I find it mildly ironic: In this new millennium, we have discovered many other solar systems with planets. And just recently, we found a possibly habitable planet around a nearby star (around 20 light years away). It is more massive than Earth, but probably still small enough to not be a gas giant like our outer planets (or like the other exoplanets found so far... that is to say, planets circling other stars.) Gravity would be uncomfortable (twice or possibly thrice as strong as here) but it is still within the bounds of what a human body could adapt to, especially if growing up there, without the need for an exoskeleton or genetic modification. (I wouldn't recommend standing straight up and down without moving, though.) The atmosphere is naturally unknown for now, but if that solar system had a similar history to our own, there would probably be lots and lots of carbon dioxide. This would have to be changed before we could settle there...

But most likely we'll never even try. I mean, we have not even gone back to the moon. When I was a kid in the age of Apollo and the moon landings, we thought that by the year 2000 we would have colonies on the moon and space stations as large as small cities in Earth orbit. We would have begun to settle on Mars, only scientific expeditions yet, but with every intention of colonizing it eventually. That's what we have always done, after all, colonized whatever land we found. But since then, something has changed. I think it is us.

I am not sure what caused the change. Perhaps when we saw this blue and white sphere from outside, we realized how unique and precious it was. Though you have to wonder, with the wars that continue to break out from time to time, how much of an impression it really made on us. Perhaps the reason why we turned our back on space was purely economic. Economics have grown to more or less replace politics in much of the world, except for the occasional war. And the wars are mostly started by the few people who don't worship money... and even then probably because they don't have enough of it to grow attached to, only just enough to envy those who have plenty.

Another reason is something that happened almost at the same time as the space revolution: The sexual revolution. Until my childhood, fertility was high all over the world. Various means to prevent pregnancy were known since ancient times, but most of them were dangerous, unreliable, uncomfortable or all of the above. With the simple and almost harmless contraceptive pill for women, children were no longer an accident for the cautious, rarely for average people and frequently only for the poor and less than gifted. (More about that in many other entries.) The short of it is, women had so much power to plan their family size that the population explosion stopped in its tracks. It was still a big deal when I was young, but this was more out of inertia. We expected that humans would continue to breed unchecked. But this did not come to pass. Now only poor countries have lots of babies. The USA is still growing, though some of this comes from recent immigrants. In Europe and Japan, the native population is already beginning to decline.

We no longer have to settle other planets to find a way out for our teeming masses. By the latest estimates, human population will culminate around 10 billion in the middle of this century, then decrease gradually. How far it will decrease is uncertain. It depends on what cultures will dominate in the future. We are still trying to sort that out. It seems likely that any culture that completely downplays reproduction will become less important, unless it has some awesome way of infecting other people with its values. Likewise any culture that glorifies reproduction will grow in strength through numbers, unless it is highly susceptible to subversion by other cultures. That could easily happen, though. For instance the Catholic countries of southern Europe are supposed to celebrate fecundity as enshrined in their religion, but in practice they seem set to almost halve their population for each generation. Of course there are other cultures that are more fertile, but I have a hard time believing that any culture that people run away from is likely to rule the world.

So there we have it. Just when we've discovered other solar systems with planets so close we could conceivably get there, we're not really interested in them anymore. One planet is quite enough. I guess this explains why we haven't seen any aliens: They haven't seen us either, after all, even though we now have the means to get out there. Laws of nature – and not least laws of economics – will make sure it will never be trivial to cross the stars. And now we don't even have a need to. All we have left is a mild curiosity, which I suppose will cause us to build new and better telescopes... if they don't cost too much. We'll probably not even send unmanned space probes. After all, they won't arrive till we are dead, and who cares what happens then?

Of course, if we could drastically extend the human lifespan, exoplanets would be more interesting. But at present there is not much chance of that. Or at least the people who dabble in that kind of science are not talking with the ones who dabble in space science. We sure are human after all. When we think about it that way, it may be just as well that we never make it to Alpha Centauri. We have a long way to go down here on old Earth.