“Let’s say you’re an evil Imperial overlord in the Star Wars universe, and you want to keep the rebels in line. You should build something they fear, say, a Death Star. How much will advancing your evil plans set you back? Short answer: it’s more expensive than you can possibly imagine.
Even if you can imagine quite a bit, Centives, the economics blog of students of Lehigh University, says it would cost “$852,000,000,000,000,000. Or roughly 13,000 times the world’s GDP” to build the Death Star…and that’s just the cost of steel production.
It turns out that it would take more than money to build a fully operational battle station. It would take cold, hard steel, made from hot molten iron. Although the Earth’s crust doesn’t have enough, the Earth’s core, on the other hand, has iron aplenty. In fact, Earth has enough iron at its core to produce 2 billion Death Stars—a veritable Death Galaxy.
But let you think it’s a simple task of Force-Lifting the molten liquid and molding it into shape, consider this:
Firstly, the two billion death stars is mostly from the Earth’s core which we would all really rather you didn’t remove. And secondly, at today’s rate of steel production (1.3 billion tonnes annually), it would take 833,315 years to produce enough steel to begin work. So once someone notices what you’re up to, you have to fend them off for 800 millennia before you have a chance to fight back.
So instead of constructing a technological terror or two, it might be better to try actual diplomacy. If nothing else, it’s absolutely more cost effective.”