While I have you captive in my own post's comment section... I recently met with someone pretty businessey on the forefront of commercial space tourism (no, it wasn't Musk, people, sorry). I asked him whether or not there were certain engineering regulations his company is considering to minimize space pollution in anticipation of imminent regulations. He told me that the commercial space accident/life insurance providers would have enough incentive to clean up the low earth orbit debris cloud. I'm not so sure how to crunch the numbers when human life is in the equation, so I guess this is where quantification breaks down and we have to defer to qualitative analysis, which of course pits human life against free market Keynesianism, just like usual. What are your thoughts on regulatory vs. laissez-faire incentivized space pollution cleanup efforts?? P.S. any help from the business-minded comment-reading lurker is appreciated. No, seriously, anyone, feel free to demolish my concerns with an argument. Also, ButterflyEffect, I would like to add to francopoli's reply that yes, the Earth's magnetic field changes polarity orientation on average approximately every 500,000 years, and that as best we can tell, we're overdue for a flip. Paleomagnetism suggests that it's been 720,000 years or so since the last magnetic field inversion, so we assume that we're about 220,000 years overdue (of course francopoli is always right). And indeed, it is happening, the Earth's magnetic moment (overall field strength) has been declining for at least the last 200+ years, ever since we started keeping tabs on it. The reversal takes place on timescales of thousands of years (francopoli is right again), not instantaneously on winter solstice, 11:11:11 AM of 12/21/2012... which would have been infinitely more badass, naturally. I also agree with franc that our technological abilities are now far outpacing the engineering challenges presented by magnetic field reversal, so it will essentially have been planned for long before it happens. wasoxygen, I would love to discuss the economics of this with you in the arena of your choosing.