If you’ve entertained thoughts of building a full-scale Death Star, prepare for a devastating reality check. The folks over at Centives crunched some numbers and determined that, based on the density of a modern warship and scaled up, it would take about 1 quadrillion tons of steel to build one Death Star. Even though Earth’s iron supply is sufficient to produce an astonishing 2 billion Death Stars, production of the required amount of steel would take 833,315 years. And the cost? In 2012 dollars all that steel would set you back about $852,000,000,000,000,000 – or roughly 13,000 times the world’s GDP.