One of the three great demographic trends unfolding on the planet (along with the developing world baby boom and the decimation of young adults in countries hit hard by AIDS) is the aging of the developed world.

As we explored before, if you want to, the odds are excellent that you'll live to see 100. If you're under 40, live in the developed world, have decent genes, take reasonable care of your health, and don't have some unlucky accident, you can probably choose now to be healthy, hale and alert into your 100s (possibly decades longer). Babies born today in wealthy countries may well routinely live to 120, many medical demographers think.

Time magazine has a pretty good article on How to live to be 100, including a much-abbreviated version of the various actuarial quizes out there which claim to predict how long you're likely to live. The complete text should be available online next week.

As Bruce Sterling has written, "When you live a really long time, it changes everything" What's less explored, though, is how the planet will changed, when many, many people live to staggeringly old ages. Demographics may not exactly be destiny, but nothing escapes their influence.