How Much Science Is Behind Star Wars' Starkiller Base?

Is there any real science behind the weapon, “Star Killer” from Star Wars: Force Awakens?
Artist’s impression of a black hole feasting on matter from its companion star in a binary system. Material flows from the star towards the black hole and gathers in a disc, where it is heated up, shining brightly at optical, ultraviolet and X-ray wavelengths before spiralling into the black hole. Part of the disc material does not end up onto the black hole but is ejected the form of two powerful jets of particles. On 15 June 2015, the black-hole binary system V404 Cygni started showing signs of extraordinary activity, something that had not happened since 1989. The system consists of a black hole about twelve times more massive than the Sun and a companion star about half as massive as the Sun. The renewed activity is likely caused by material slowly piling up in the disc, until eventually reaching a tipping point that dramatically changes the black hole’s feeding routine for a short period. Since the first signs of such unusual activity, astronomers worldwide have been observing this exceptional system with ground-based telescopes and space-based observatories, monitoring the source at many different wavelengths across the electromagnetic spectrum. Image credit: ESA/ATG medialab

Artist’s impression of a black hole feasting on matter from its companion star in a binary system. Material flows from the star towards the black hole and gathers in a disc, where it is heated up, shining brightly at optical, ultraviolet and X-ray wavelengths before spiralling into the black hole. Part of the disc material does not end up onto the black hole but is ejected the form of two powerful jets of particles. On 15 June 2015, the black-hole binary system V404 Cygni started showing signs of extraordinary activity, something that had not happened since 1989. The system consists of a black hole about twelve times more massive than the Sun and a companion star about half as massive as the Sun. The renewed activity is likely caused by material slowly piling up in the disc, until eventually reaching a tipping point that dramatically changes the black hole’s feeding routine for a short period. Since the first signs of such unusual activity, astronomers worldwide have been observing this exceptional system with ground-based telescopes and space-based observatories, monitoring the source at many different wavelengths across the electromagnetic spectrum. Image credit: ESA/ATG medialab

Originally posted at Forbes!

Here’s the thing with looking for science in the Star Wars universe: you’re already in a world where lightsabers work, The Force is a real thing, and faster-than-light travel is possible. This is not a universe where our laws of physics are consistently applied, so a healthy dose of suspension of belief is required. When I go into a Star Wars movie I’m not really looking for perfect physics. So what I’m going to do here is lay out a couple of issues with Starkiller Base, were it to be found in our Universe, which it isn’t. Star Wars fans, please feel free to invoke your favorite technobabble to get around any/all of these problems.

With that caveat out of the way, we can certainly look at the feasibility of Starkiller Base. Starkiller Base, in a nutshell, is a planet which has had some of its planetary innards removed and replaced with a fairly sizable weapon. This weapon is charged by finding a star, and vacuuming the star in its entirety into the planet. This star-energy is held inside the planet by plot devices, and then the star’s energy is fired out of the planet to vaporize unsuspecting planets.

The puzzling, fascinating surface of Jupiter’s icy moon Europa looms large in this newly-reprocessed color view, made from images taken by NASA’s Galileo spacecraft in the late 1990s. Image credit: NASA/JPL-Caltech/SETI Institute

The puzzling, fascinating surface of Jupiter’s icy moon Europa looms large in this newly-reprocessed color view, made from images taken by NASA’s Galileo spacecraft in the late 1990s. Image credit: NASA/JPL-Caltech/SETI Institute

Firstly; even though Starkiller Base is covered in ice, it’s still a rocky planet, which we know because we saw it starting to come apart at the seams towards the end of the movie. There’s no explicit size for the planet given, so I’m going to assume that it’s about Earth-size. I have two justifications for this assumption: the first is that everyone is walking around on it normally, which means its gravity has to be about normal, and second, it makes my life easy.

If Starkiller Base is about Earth sized, then that trench going around its equator is really deep. I did some rough math, based on the size of the planet in images and the depth of the trench in images, and scaling to the size of the earth. If Starkiller is Earth-sized, that trench is 581 miles deep. For scale, if you started at the southern border of Colorado, and drove north until you had hit the northern edge of Wyoming, you would have driven 560 miles. Google Maps informs methat’s over an 8 hour drive.

Fun fact: The Earth’s crust, at its deepest, is a little under 44 miles thick. This trench, if we were to install it on our own Earth, would be more than ten times deeper than our deepest rock, and would plant the base of it firmly in the mantle, which is made of a plastic-y form of melted rock. Installing this on the Earth would almost definitely cause some havoc with our plate tectonics, assuming of course that we can insulate such a structure from our planetary heat to keep it from melting immediately. But perhaps Starkiller Base doesn’t have tectonics (or an internal mantle), as it’s covered in ice and we didn’t see any volcanoes lurking on the horizon.

Secondly; Starkiller base can absorb an entire star in a pretty short period of time. Our universe does contain an object which can siphon material away from a star, but that object is a black hole. Starkiller base is definitely not a black hole, even at its core. A black hole would be gravitationally distressing to walk near, and it is a terrible place to put spacecraft, which would have to spend a huge amount of energy to escape its gravitational influence. Furthermore, even a black hole, as the most extreme gravitational object possible, is not very good at killing stars.

Artist’s rendering showing the black hole and its accretion disk with a disk wind fully established. Image credit: NASA/Goddard Space Flight Center/CI Lab

Artist’s rendering showing the black hole and its accretion disk with a disk wind fully established. Image credit: NASA/Goddard Space Flight Center/CI Lab

Black holes are frequently found in binary systems with other stars in our universe. This happens if two stars have spent their whole lives circling each other, having formed near each other, but one of them was slightly more massive than the other.  The more massive the star, the shorter its lifespan. The more massive star can go through its death throes and create itself again as a black hole, all without moving from its orbital dance with the other star. These binary black holes do drain the outer layers of their companion stars away, but it is a long, slow, tedious, & inefficient process, which drags on over millennia. It’s certainly not the quick deflation of the star we saw in the movie.

I’m going to skip over the whole “storing of an entire star’s worth of energy within a much smaller planet” bit, because that’s even less plausible than the rest of the premise of Starkiller Base. The movie seems to recognize this, so there’s a whole plot device dedicated to fixing this problem; the thermal oscillator. In the movie it’s a handy device that lets you not destroy the planet with all the matter/energy you’re storing, while also not compressing your matter/energy into a black hole. Thermal oscillators do not exist, so we’re well into Star Wars Physics and not our own Universe’s physics with this part of the story.

However, there was one piece of glorious physics to Starkiller base- right at the end. After the heroes manage to explode all possible mechanisms of keeping a whole star contained within the planet, physics as we know it returned to the scene. If you have a star’s worth of matter, no longer contained artificially, in a region of space which is dense enough to create a star, but not dense enough to collapse into a black hole, what you get is a star!  So as soon as all of the pieces keeping Star Wars physics operational were removed, it makes perfect sense for Starkiller Base to be consumed in the making of a brand new star, right next to where the old one had been.

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