there is already a death star: the moon. it was towed into our solar system by aliens.
In this view captured by NASA's Cassini spacecraft on 13 February 2010, Herschel Crater dominates Mimas, making the moon look like the Death Star in the movie "Star Wars."
Based on the build time estimate on the lego milenium falcon, it would take about 7.5 million people working their entire lives without breaks to build this. I can think of 7.5 million people that are useless enough to only do this, so let's do it!
whatif.xkcd.com - far more interesting analysis of some physics questions. (Week 2 was awesome about the baseball pitched at 90% the speed of light.)
