Have you ever thought about destroying a planet? Of course you have, especially if you’ve ever seen the "Star Wars" films. After all, three of the seven films feature planet-destroying superstructures. This video by YouTube user Scott Manley – a self-confessed "Star Wars" fan – looks at a few of the scientific ways of addressing this fairly complex problem. Be warned: There are mild "The Force Awakens" spoilers ahead.
First off, the amount of energy required to overcome the force of a planet’s gravitational field is explored. This is largely dependent on something called the “gravitational binding energy,” a value that describes the minimum energy required for gravity to hold something together. It can be calculated for any spherical object, including a planet, for which the mass and radius is known. Earth, for example, has roughly two hundred million trillion trillion joules of this binding energy – which, as you can imagine, is quite a lot.
Nevertheless, this video suggests that the original Death Star, with its hypermatter power source, would certainly have had enough energy to destroy Earth. After all, it vaporizes Alderaan, very much an Earth-like planet, sending chunks of it into space at over 10,000 kilometers per second (6,214 miles per second).
As for Starkiller Base, which obliterates multiple planets using an energy beam traveling at superluminal (faster-than-light) speeds? That’s an entirely different kettle of fish. Check out the video and see for yourself.