Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!akgua!sdcsvax!sdcrdcf!hplabs!sri-unix!OC.Trei@CU20B From: OC.Trei%CU20B@sri-unix.UUCP Newsgroups: net.sf-lovers Subject: Death Star weapon. Message-ID: <12537@sri-arpa.UUCP> Date: Thu, 19-Apr-84 17:04:24 EDT Article-I.D.: sri-arpa.12537 Posted: Thu Apr 19 17:04:24 1984 Date-Received: Fri, 11-May-84 08:19:33 EDT Lines: 81 From: Peter G. Trei After seeing a lot of casual talk on this board about the Death Star and its ability to blow up planets, I decided it was time to get a little more specific. Just how much energy does it actually take to blow up, say Earth (we dont have the stats for Alderan). For the sake of argument, I have defined a planet as being 'blown up' when its fragments are receding from its original location fast enough so that they will never coalesce again. In effect, the entire mass of the planet has to be accelerated to its own escape velocity. Using the back of a very large envelope, this is what I came up with. (I hope someone checks these figures). Earths density : 5.52 g/cm^3 Diameter: 12,757 km Escape velocity: 11.3 km/s => vol = 1.087 E13 km^3 mass = 6 E25 kg => Need 3.8307 E33 Joules to blow up. (Of course, this ignores the planets structural strength, and assumes 100% efficiency in production of kinetic energy with the appropriate vectors.) Thats a lot of EverReadys. What could be the source of this energy? Can the Death Star hold that much? The answer is yes, if they use mass conversion at high efficiency. Here is the calculation for the mass equivalent of that energy: 1 kg = 9 E16 Joules (from E = mc^2) => need 4.2555 E16 kg of mass. If this mass is at the same density as the Earth, you will require 8100 Km^3 of it. In one lump, this is a spheroidal rock about 25 Km across. Of course, it gets smaller if you use lead, or neutronium. Some people have been saying that the DS is '100 miles' across. I find this difficult to accept. From its appearence in the movies, I would have said that its diameter was 5-10 miles at the outside. This obviously leads one to wonder where they keep (a minimum of) 4 E16 kg of ammo, and still leave room inside for spacefighter dogfights. Even using antimatter does'nt really help, at best it improves your ammo's effiency by a factor of two. I am forced to the conclusion that the DS's main weapon is not sending out all of that energy itself. Somewhere along the line more energy is being produced, and delivered to the target. The 'chain reaction' hypothesis thus appears. I can think of two ways to do this: 1. Induced fusion. Back when they were testing the first thermonuclear weapons out in the Pacific, some people entertained serious worries that the shock wave of the bombs would induce fusion in the light water of the Ocean, leading to a chain reaction in which all the hydrogen of the Earth would fuse. Also, think of the current work on inertial confinment laser induced fusion. I have heard that the Antares laser produces (momentary) flashes of 4 E19 watts. 2. Matter conversion ray. In one of his Known Space stories, Larry Niven had a weapon, the ray of which would convert anything it touched to energy. Even on an airless moon, you could see the ray because of the destruction of interplanetary gas. At one point the protagonist accidently allows the ray to intersect the horizon, causing a major earthquake. It would be just dandy as a planet destroyer (BTW, this was a HAND WEAPON!). Peter Trei oc.trei%cu20b@columbia-20.arpa PS: I wonder how many times in the past someone has actually done this calculation! Hail Eris! PT -------