h a l f b a k e r yA riddle wrapped in a mystery inside a rich, flaky crust
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Here's one that might actually be baked...I'm not sure.
Take a 10,000-lb block of stainless steel, sufficiently streamlined and heat-resistant to withstand enormous atmospheric heating.
Load it on an SR-71 Blackbird and fly it up to 100,000 feet; at that point, a ramjet will fire on the weapon
and push it up to 300,000 feet. Set up for a general trajectory, and release the bomb. When it hits, at close to 4 km/sec....
I worked this out sans air resistance because I haven't taken many physics courses (which is a problem, since air resistance is a huge factor at the speeds i'm working with), but the final amount of force produced by this impact comes out to roughly
50,000,000,000 Newtons.
(Ie. 50 GN, meaning that there is enough energy in that bomb to push a 50-billion kilogram object one metre in any direction).
Suffciently impressive, no? Lockeed Martin did some experiments and found that something much smaller than this, and dropped from lower altitude, would still dig a hole 130 feet deep.
Dumb Rocks
http://www.halfbake...m/idea/dumb_20rocks
Not the same thing, actually: this idea launches the missile from the ground rather than dropping it from space. With a huge loss in destructive power. (Better off just throwing the fuel at the enemy.) [DrCurry, Oct 05 2004, last modified Oct 17 2004]
For thimble
http://www.halfbake...emorial#top_of_page
[egbert, Oct 05 2004, last modified Oct 17 2004]
[link]
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Pretty Half-Baked in a lot of science fiction, I'd say - Use Of Weapons by Iain Banks springs to mind... mfd? |
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Why is this half baked? I liked it. |
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I think it'd actually be possible, too. |
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Everybody knows that Newtons are wimpy European units! If you are taking pounds and feet, how come Newtons? What’s wrong with good old ft-lbs? |
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Not entirely sure why you need a Blackbird to launch it, as opposed to a plain old ICBM. |
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Also, you'd be better off measuring the impact in terms of kilotons, if you want to sell this as an alternative to low grade nuclear weapons. Or, in this case, 0.00015 kilotons. |
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The sci fi implementations that yamahito refers to involve lobbing rocks from space, in which case the explosive power does begin to match that of nuclear weapons. |
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Larry Niven proposes kinetic weapons (and I'm paraphrasing here) "like wrenches with guidance surfaces" in one of his studies. I think it's 'Playgrounds of the Mind', but I'm not positive. |
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Smaller than yours, but more tactical (and practical). |
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I believe NASA has been experimenting in this field. |
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. . . and then there's the elite few. |
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I've read [perhaps apocryphally] that the U.S. military has on occasion done something pretty close to this: for a surgical strike, replace the warhead on a guided bomb with concrete. Allows one to take out a target with minimal collateral damage. |
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BTW, I think your dimensional analysis is flawed. The kinetic energy at impact may be readily computed sans air friction; with air friction, exact computations require knowing the ballistic profile of the object. The force of impact, however, is a function of how much "give" the slug and the target have. The distance the slug can push is a function of the resistance force the struck object provides, not its mass. |
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Unfortunately, their military doesn't employ anyone capable of doing quick mental calculations. Those sort of people are all busy making a fortune on the stock market. |
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<hitches braces>Twenty shillings to a pound is sixteen ounce and several foot pounds per slug fortnight for a bushel o' barley. You knew where you were in them days. Course back then we had an empire...<hitches braces>. |
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<tucks blanket under [Egbert]'s arms, wipes drool from his chin, pushes wheelchair out onto terrace so he can get some fresh air> |
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Re the idea: Smart Rocks are pretty Baked. |
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Yeah, nice catch, [bris]! |
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//quoting their decimal dollar values in silly fractions, like 31/64 of a dollar//
The american stock exchanges dropped that a while back, UnaBubba. |
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Taking the bait is just the beginning. Now you've got to reel that big sucker in!
The UK Money Market still operates in fractions. I was lending money out at 4 1/16th percent only this morning. Every now and again some smart-alec tries to go over to decimals but, I'm pleased to report, the forces of reactionary conservatism beat them down every tiime. |
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Supercat, I'm assuming a surface with very little give (ie. a hardened steel bunker) and a distance of deceleration of approximately 10 metres (oh, and all the metric units are because it's canada, OK? |
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And decimals make more sense, becuase they're easier to do calculations with. |
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for that matter, we could just as easily be using base 8 or base 16 or base 12 or whatever and still be able to use decimals.... |
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I dunno. I still think of short distances in feet and inches, long distances in miles, and weights in pounds. All other units are metric. |
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How many Rods Tigers in a hectare again? Or is that in a peck? |
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DrBob: Yeah, well ever since you guys went to decimal currency it's been impossible to properly dress a bride (with sixpence in her shoe). |
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If we'd just all count in octal instead of silly decimals then the systems would line up so much better. It's got better musical rythm, it doesn't lose sigfigs in halving division over time, it doesn't discriminate against cartoon characters with only 3 fingers and a thumb... |
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I'm challenging the position that a sufficiently powerful bomb must be made of steel. Perhaps something more porous is in order, specifically because it can't survive atmospheric resistance intact. |
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Look up the Tunguska explosion of 1908. An object, probably a huge chunk of ice, came in at cosmic speeds, disintegrated in the atmosphere, and decimated over 2,500 sq. kilometers of forest. It's not a surgical strike, but a good, cheap, non-nuclear WMD. |
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Better rev up your ice-maker. |
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Larry Niven and Jerry Pournells weapon system was christened "Thor" I believe and was described in the man-kzin war series. |
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However I have a feeling it was originaly mentioned in a future-weapons briefing the guys at JPL (including Pournell) did for the pentagon/NASA in the early 70s..... |
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see below for Authors comments on said system (amongst others) |
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http://www.jerrypournelle.com/slowchange/mega.html |
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Heinlein "The Moon is a Harsh Mistress" - rebels on the moon use a mining apparatus to pick up rocks from the moon and huck them at the earth. |
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//Heinlein// And Ian Banks (there was a automated lunar miner called Moonwolf that rail-gunned mineral chunks at Earth's cities.) |
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Hmm...I think density might be important. |
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remember, the equation is F=ma, where a can be the deceleration magnitude. as you can see, a large value of m increases the force by that factor; so you could conceivable have an enormous block of styrofoam doing the same damage as a small block of steel but over a larger area. |
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I think the biggest issue in this respect is that a chunk of styrofoam 100 feet on a side is a little tricky to carry on an ICBM, let alone an aircraft. maybe a steel block (stainless for fun - like a DeLorean) with a tungsten or industrial diamond nosecone for heat resistance and some ceramic or carbon-carbon sheets farther back. |
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or make the whole thing out of tungsten - then it can be smaller and more streamlined, without the need for heat resistance (i believe tungsten has the second highest melting point of all compounds, with diamond being higher?) |
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Or at least the melted remains. |
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//Now there's a concept for you: An Arcturan Penal System freighter carrying 20 million crowbars to the mines of Magellan, suffers a hull rupture in the vicinity of Earth. It rains crowbars for 3 days...// |
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But due to a gross miscalculation of scale, the entire shipment is eaten by a small dog. |
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As do most of us (linky). |
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A description of a destructive weapon of mass destruction, with ne'er a mention of what it is built to destroy.... |
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I went to an air show once. There was a stand there staffed by chaps from the host countries' air force. And they had all sorts of interesting kit lying about for people to look at and tap and prod. I asked the chap what a particularly nasty looking missile was for. He spent a couple of minutes telling me its range, and speed and choice of warhead. When I asked him again, "what is this missile designed to DO", he looked at me patiently, and again explained how fast, and how far. I said, "but when it GETS to its destination, what then?". Then when he realised that I wanted to know how many humans it was designed to vapourise, he got really stroppy and told me that I should move along as I was causing an obstruction. |
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People should be more careful with bombs and stuff, they are really bloody dangerous. |
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This was seriously examined by Lockheed (the company that built the Blackbird) around the same time it was built. However, the Air Force thought they were nuts. |
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-Just a bit off topic-
military doesn't employ anyone capable of doing quick mental calculations-
Oh really? What am I doing working toward a PhD. in Biology for? Hmm... No, I guess you're right, the military really is dumb. That's why we're full of pilots, doctors, nuclear technicians, aircraft mechanics and so on..... |
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A 10,000 kg sphere would, on a fairly typical fair-weather day, have a terminal velocity of approximately 502.13 m/s due to air resistance. This would mean a terminal kinetic energy of about 2.521 gigajoules. Sounds like a lot, huh? Well, no. One ton of TNT explodes with an energy of 4.181 gigajoules. I'd wager that one ton of TNT is less expensive than 1,000 tons of steel. |
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Yes, but that's terminal velocity. It gets a lot faster than that if you "drop" it from a moving vehicle. |
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Actual pencil whipping was done by Germans for hyper velocity bombs during WWII. The plan was to use a rocket plane with a very high altitude to bomb US cities. Jet bomber would deliver kinetic weapons that were much lighter than conventional explosive bombs with much more damage for same weight of explosive. The concept was to use a bomber that skiped on the upper atmoshere loaded with iron bombs. With the correct trajectory these hyper velocity weapons would wipe out large areas by laying down a pattern onto the delivery or target landscape without the need for explosives. These hyper velosity weapons required less weight per damge area on the city scape, primary target model New York City. These plans seemed to be an efficient delivery system for hyper velocity weapons to use an atmospheric skip jet bomber technique. |
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That's the terminal velocity at what altitude? |
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And 10,000KG is only 10 tons. |
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I thought it was 11 tons....hmmmm, must be the new my-nep math. |
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This isn't gonna work too well. A nuke has power about equal to a trainload of TNT. The fuel that's burnt lifting/accelerating this steel slug equals maybe a few boxes of TNT. |
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