by CRYSTAL ROSENE
December 16, 2016. That was the magnificent day that Rogue One: A Star Wars Story was released in Canada, and I hope that by now most of you have made time to go see it. If you haven’t…not to worry, you’ll find no spoilers here. In any event, the release of another Star Wars movie has me thinking about the science behind some of their most fantastic creations- after all, this is what a math/physics degree is for…right?
Henceforth, I will be delving into the physical possibilities (or impossibilities) of the Death Star. According to Wookieepedia, the Death Star was a ‘moon sized deep space mobile battle station’ with the capability of destroying an entire planet with a single pulse of its kyber powered super laser. (I will make this one disclaimer: in an attempt to explain the limitations of the Death Star using known physics, we must conveniently forget that the actual energy source is powerful Force-attuned crystals that grow in the far reaches of the galaxy…)
Moving on. We have a giant sphere of doom flying around the galaxy ready to blow up entire planets at the touch of a button. Now, take a brief minute to think about the tragic fate of Princess Leia Organa’s home planet, Alderaan: with one laser pulse and under 3 seconds, the entire planet was completely obliterated. This is where the physics fun begins.
First of all, let’s determine the minimum amount of energy required to tear apart the planet. Wookieepedia describes Alderaan as a 4-5 million year old Earth-like planet, so for the sake of calculations, we’ll just pretend it is Earth from here on out. The approximate gravitational binding energy of the Earth (U) is found as follows (where M is the mass of Earth, R is the radius, and G is the gravitational constant):
This is the minimum energy required to deal any significant damage to the planet. Our sun gives out 3.8×1026 J of energy per second, so it would take approximately 6.8 days for our sun to put out as much energy as the Death Star uses in 3 seconds! However, as we see in A New Hope, there is clearly much more energy than that, as the explosion is aggressive enough to eject chunks of material in all directions at tremendous speeds.
Other scientific inconsistencies surrounding the Death Star are present as well, including the fact that those on board Vader’s ship weren’t either vaporized by the intense heat or ripped apart by shrapnel, given their proximity to the explosion. These points aside, the sheer amount of energy that is needed is so tremendous that it alone is likely enough to disprove the possibility of a real Death Star, at least for now.
From a physical perspective, it therefore seems slightly less worrisome that some Star Wars loving aliens have made their own working Death Star prototype and are now off terrorizing the galaxy…unless they’ve found the kyber crystals…