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Global Cooling
In article ,
PcMan writes: To block just ONE PERCENT of sunlight, you need to block some 1.35 million square kilometers. OK. (This assumes a grain blocks its geometric area, but it actually blocks a factor of two more because of scatttering, but we won't worry about that.) Assuming you grind down your regolith to about cement-dust scale (10 nm grain size), you will need some 53 million metric tons. But I don't get this. The area is 1.35E12 m^2, and the area of one grain is 8E-17 m^2, so the number of grains needed is 1.7E28. Each grain has a volume of 5E-25 m^3 and (at density = 3 g cm^-3) mass of 1.6E-27 kg for total mass 27000 tonnes. What am I doing wrong? Whether this (if correct) is small enough to make the idea feasible, I don't know. -- Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA (Please email your reply if you want to be sure I see it; include a valid Reply-To address to receive an acknowledgement. Commercial email may be sent to your ISP.) |
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