SciAm on vacuums and subways, and a novel I love

http://blogs.scientificamerican.com/cocktail-party-physics/2011/07/11/a-series-of-tubes/ The physics in this post are a bit beyond my level of understanding+ability, but it's well written and exciting to read nonetheless. Thanks Jennifer Ouelette for reminding me of Downsiders - a YA novel (which I loved!) about underground dwellings in NYC.