The Death Star: An Uneconomical Way To Blow Up Planets

It’s been one of those bad blogging days. Usually, I’d start the day rifling through the day’s space news on the mainstream to work out what has been going on in the world. If some exciting stuff has been going on, my notebook will be filled with scribble, usually priming me for an afternoon of writing for the Universe Today or Astroengine. Usually. Today, although I got up bright and early, my writing ability took a U-turn much like the abysmal LA winter weather (grey and soggy). Writer’s block.

Bloggers writers block is especially frustrating as there is no end to the cool stuff going on in space (and even if there isn’t, I can usually unearth something not-so-cool and make it cool by doing a bit of research), but for some reason my brain wouldn’t budge. Not a bit. Plus I’m co-writing a book (but I’m not saying about what… yet), so it was a double-whammy bad writing day.

I gave up, had a bath, read a book and watched two episodes of Battlestar Galactica. Awesome…

Still unsatisfied, I decided to have a look around my blogospheric neighbourhood. I took a walk alphabetically down the road from 21st Century Waves, stopping in for a cup of tea at Bad Astronomy, passing Gia’s Blog with a friendly wave, telling the Noisy Astronomer to keep the volume down, checking in on the telescope addict at Simostronomy, taking time to admire Nancy’s stack of new articles at the Universe Today and heading home after checking out how weird our world really is (my full blog stroll can be found to the right of the page). That little adventure took up a few hours of my afternoon as I realised this was going to be more of a reading day than a writing day.

Done with space, I had a wonder over to the gadget blogs, stopping at GearCrave.com. And then I see it, the inspiration I was looking for…

A guy had spent the time to work out how much the Death Star from Star Wars would really cost to build. It’s not space science, but I’ve always got time for sci-fi. The full treatment of the Death Star budget can be found at RickGold.info, but if the Death Star were to be built from scratch, using 134 quadrillion tonnes of steel, it would cost $15,602,022,489,829,821,422,840,226 (including materials and transportation, not including slavery or the cost of Darth Vader’s wardrobe. The precision of the figure is done, presumably, for comic effect). That’s 15 Septillion US dollars.

Me being me, I then had a look around to find out any other interesting little nuggets of information about the Death Star. Sure enough, over at Built on Facts, Matt Springer applied some real physics to working out how powerful the Death Star’s superlaser would need to be to destroy a planet, like, say… the Earth.

When we saw the Empire do some planetary blending in Star Wars IV: A New Hope, the planet Alderaan was snuffed out of existence by the Dark Side’s secret weapon. However, little information was provided as to how the thing worked or how powerful it was. So how can you find out the power of the Death Star’s superlaser?

It’s all a question of gravitational energy. You have to pull apart the planet, giving each chunk of rock enough energy to be expelled from the overall gravitational pull of the assembled planet. Springer goes through the mathematical steps to work out how much energy would be required to rip apart the Earth, and in a similar fashion to the Death Star construction costs, the result is huge. The minimum energy required to destroy the Earth (and this is the bare minimum, you need way more juice to create some neat pyrotechnics and CGI shock waves) is 2.2 x 10³² Joules. That’s the equivalent total energy generated by the Sun, for a whole week.

We knew that the construction of a Death Star would be fairly pricey, but to generate that kind of energy, in a single second, to destroy the Earth, has forced me to re-think my plans for global domination…

I love my days off.