Hi, I'm the author of the blog post (on twitter at @aatishb). I'd be happy to get your feedback and constructive criticism on this analysis. My take is that, given the many assumptions, I'm pretty darn surprised that it gave a reasonable answer. On the other hand, it just shows that you can go a long way with some dimensional analysis and a few crude measurements. Look forward to hearing your take on the writing, analysis, and ways that you think it could be improved overall. Cheers.