tinman Posted November 3, 2005 Report Share Posted November 3, 2005 I have kept my campaign to within reasonable extrapolations of modern technology for the most part (it's currently set five years ahead of today), and I have a question about the feasibility of an anti-superhuman weapon I'm thinking about. Basically, the idea is that a powerful laser creates a tunnel of superheated air between the weapon and the target. This tunnel is, for a short time, much less dense than the surrounding atmosphere. Immediately after the laser fires an electromagnetic launcher fires a projectile at very high velocity down the same path, taking advantage of the vastly reduced air friction inside the air-tunnel to prevent the projectile from being significantly slowed or heated to the melting point by friction. The result is that targets can be engaged at long range with projectiles travelling many times faster than should be possible in an atmosphere. Would such a weapon actually be capable of working in that fashion? Would the power requirements render it too impractical to use? Would I be better off just nuking them from orbit? HEROphiles, lend me your opinions. Quote Link to comment Share on other sites More sharing options...
McCoy Posted November 3, 2005 Report Share Posted November 3, 2005 Re: A question to the physics-minded... I have kept my campaign to within reasonable extrapolations of modern technology for the most part (it's currently set five years ahead of today), and I have a question about the feasibility of an anti-superhuman weapon I'm thinking about. Basically, the idea is that a powerful laser creates a tunnel of superheated air between the weapon and the target. This tunnel is, for a short time, much less dense than the surrounding atmosphere. Immediately after the laser fires an electromagnetic launcher fires a projectile at very high velocity down the same path, taking advantage of the vastly reduced air friction inside the air-tunnel to prevent the projectile from being significantly slowed or heated to the melting point by friction. The result is that targets can be engaged at long range with projectiles travelling many times faster than should be possible in an atmosphere. Would such a weapon actually be capable of working in that fashion? Would the power requirements render it too impractical to use? Would I be better off just nuking them from orbit? HEROphiles, lend me your opinions. Humm, If I recall my physics class correctly, the superheated air would have more resistance that normal air. It is in the couple of nanoseconds between the time the laser shuts down and the air moves back in tot he tunnel (probably with a thunderclap) that you would have the reduced friction. Power requirements, probably something equlevent to a lighting bolt to target the thing. What about giving the projectiles a super-aerodynamic shape or a super-teflon frictionless coating? Or both, and making those Sx for double armor piercing? Quote Link to comment Share on other sites More sharing options...
tinman Posted November 3, 2005 Author Report Share Posted November 3, 2005 Re: A question to the physics-minded... Humm, If I recall my physics class correctly, the superheated air would have more resistance that normal air. It is in the couple of nanoseconds between the time the laser shuts down and the air moves back in tot he tunnel (probably with a thunderclap) that you would have the reduced friction. Power requirements, probably something equlevent to a lighting bolt to target the thing. What about giving the projectiles a super-aerodynamic shape or a super-teflon frictionless coating? Or both, and making those Sx for double armor piercing? Yeah, that may just be simpler. Or I could go the opposite route and rather than use small hyper-velocity projectiles, just hit them with huge moderate-velocity projectiles... ...or tungston rods from space Quote Link to comment Share on other sites More sharing options...
Cancer Posted November 3, 2005 Report Share Posted November 3, 2005 Re: A question to the physics-minded... You need a very large energy density to do the thing you mention ... which is going to be like carving a lightning-bolt-like channel through the atmosphere. This kind of thing is somewhat like the technical challenge of defending against nuclear missile attack. That means that if you can find it, discussions about ABM technologies will be relevant. Scientific American has had a few of those over the years; so has Physics Today, though the latter may not be very readable. Quote Link to comment Share on other sites More sharing options...
Dr. Anomaly Posted November 3, 2005 Report Share Posted November 3, 2005 Re: A question to the physics-minded... tinman, if you've already got a laser powerful enough for that kind of effect...why bother with the projectile at all? The laser itself should do some significant damage. Quote Link to comment Share on other sites More sharing options...
tinman Posted November 3, 2005 Author Report Share Posted November 3, 2005 Re: A question to the physics-minded... tinman' date=' if you've already got a laser powerful enough for that kind of effect...why bother with the projectile at all? The laser itself should do some significant damage.[/quote'] Good point. I wasn't sure how much energy the laser would have to put out to have the desired effect, but from the sounds of things it would be far beyond the concept I had in mind. Quote Link to comment Share on other sites More sharing options...
tinman Posted November 3, 2005 Author Report Share Posted November 3, 2005 Re: A question to the physics-minded... You need a very large energy density to do the thing you mention ... which is going to be like carving a lightning-bolt-like channel through the atmosphere. This kind of thing is somewhat like the technical challenge of defending against nuclear missile attack. That means that if you can find it, discussions about ABM technologies will be relevant. Scientific American has had a few of those over the years; so has Physics Today, though the latter may not be very readable. Hmmm, thanks for the tip. Quote Link to comment Share on other sites More sharing options...
Baphomet Jones Posted November 3, 2005 Report Share Posted November 3, 2005 Re: A question to the physics-minded... The development of this sort of high velocity frictionless projectile could make for a cool story seed, as a local speedster hero gets kidnapped for study by the R&D guys wondering why he or his costume don't seem to be harmed by the friction of his high speeds. They may even just steal his costume or shoes to see what they're made of and how they stand up to the stress. Quote Link to comment Share on other sites More sharing options...
Dr. Anomaly Posted November 3, 2005 Report Share Posted November 3, 2005 Re: A question to the physics-minded... Hang on, I just remembered something that may be useful, if you still want to use a projectile... It's possible to drastically lower air friction using a plasma spike in front of the...well, in the work being done, it's for aircraft, but there's no reason you couldn't apply it to a projectile, I suppose. You'd need a really high-density power source to get it to fit inside a projectile, even one no larger than, say, your hand...but it needn't last longer than 1 second or so, and thus may be within the technical limits you're setting. A brief synopsis may be found here, and a bit of Googling will turn up lots more info, if you want it. Edit: don't be put off by the 'conspiracy-theory' sort of tone the website I referenced may give...the article they're quoting for the information comes from a genuine periodical. Quote Link to comment Share on other sites More sharing options...
tinman Posted November 3, 2005 Author Report Share Posted November 3, 2005 Re: A question to the physics-minded... The development of this sort of high velocity frictionless projectile could make for a cool story seed' date=' as a local speedster hero gets kidnapped for study by the R&D guys wondering why he or his costume don't seem to be harmed by the friction of his high speeds. They may even just steal his costume or shoes to see what they're made of and how they stand up to the stress.[/quote'] This: http://www.aeronautics.ru/mach50.htm could be the key I'm looking for Quote Link to comment Share on other sites More sharing options...
tinman Posted November 3, 2005 Author Report Share Posted November 3, 2005 Re: A question to the physics-minded... Hang on, I just remembered something that may be useful, if you still want to use a projectile... It's possible to drastically lower air friction using a plasma spike in front of the...well, in the work being done, it's for aircraft, but there's no reason you couldn't apply it to a projectile, I suppose. You'd need a really high-density power source to get it to fit inside a projectile, even one no larger than, say, your hand...but it needn't last longer than 1 second or so, and thus may be within the technical limits you're setting. A brief synopsis may be found here, and a bit of Googling will turn up lots more info, if you want it. Edit: don't be put off by the 'conspiracy-theory' sort of tone the website I referenced may give...the article they're quoting for the information comes from a genuine periodical. Damn, that's just plain eerie. You beat me by 5 minutes "You have given out too much Reputation in the last 24 hours, try again later." Quote Link to comment Share on other sites More sharing options...
Dr. Anomaly Posted November 3, 2005 Report Share Posted November 3, 2005 Re: A question to the physics-minded... Damn' date=' that's just plain eerie. You beat me by 5 minutes [/quote'] And I was just thinking, "Curse you, tinman! How dare you find the same 'answer' on your own, without letting me be the purveyor of obscure knowledge!!! " (Response exaggerated just slightly for comedic value. ) Quote Link to comment Share on other sites More sharing options...
Dr. Anomaly Posted November 3, 2005 Report Share Posted November 3, 2005 Re: A question to the physics-minded... On a slightly more serious note, I've used the plasma ram as a piece of in-game tech once -- on the Quest Delta Dart, the personal aircraft of Dr. J. A. Quest of QuestLabs. (In one game the PCs were consulting with Dr. Quest on a serious technical matter, and he ended up picking them up at the airport in his aircraft for a suborbital hop back to QuestLabs' main research facility.) Quote Link to comment Share on other sites More sharing options...
tinman Posted November 3, 2005 Author Report Share Posted November 3, 2005 Re: A question to the physics-minded... And I was just thinking' date=' "Curse you, tinman! How [i']dare[/i] you find the same 'answer' on your own, without letting me be the purveyor of obscure knowledge!!! " (Response exaggerated just slightly for comedic value. ) Seeing as how you have ascended beyond the ken of mere mortals, is it possible that by merely erecting a thread that invoked your presence my search was guided by a power greater than Google? No one may know for certain, for this is the realm of faith alone Quote Link to comment Share on other sites More sharing options...
Jaxom Posted November 3, 2005 Report Share Posted November 3, 2005 Re: A question to the physics-minded... Ummm... Two words. Projectiles fall. You can never fire a bullet or any other projectile down the path of a laser from the same barrel or even one that is close. There's a reason that your sights on a rifle are sighted to a specific distance. (That's why, by the way, you see laser sights on pistols and not on hunting rifles. For 20 ft the difference is negligible. At 300 yards it is meaningful.) Quote Link to comment Share on other sites More sharing options...
Dr. Anomaly Posted November 3, 2005 Report Share Posted November 3, 2005 Re: A question to the physics-minded... Ummm... Two words. Projectiles fall. You can never fire a bullet or any other projectile down the path of a laser from the same barrel or even one that is close. There's a reason that your sights on a rifle are sighted to a specific distance. (That's why, by the way, you see laser sights on pistols and not on hunting rifles. For 20 ft the difference is negligible. At 300 yards it is meaningful.) Yes, they do...but they all fall at the same rate. If the projectile is traveling fast enough, it may reach its target well before it's fallen a significant distance. Example: throw a ball as hard as you can, and measure how far forward it traveled before it hit the ground. If the ball was 5' off the ground (appox. shoulder height) and it hit the ground 60' away, then for every 12' it traveled, it fell 1'. Now fire a rifle set at the same height. In 12' of travel, the bullet will have fallen only a fraction of an inch. That's because the bullet travels much farther and faster than the ball. Both will hit the ground after the same amount of time (more or less, accounting for differences in friction with the atmosphere due to shape, etc.) but the bullet will have gone much farther in that same amount of time. The point is, the rate of the bullet's fall, in relation to its distance traveled, is quite different from that of the thrown ball. Now compare the distance a hypersonic projectile would travel in relation to how far it falls in a given amount of time. It's perfectly feasible that a hypersonic projectile could travel a mile or more and hit its target before falling far enough to fall out of the 'tunnel' of low pressure created by a laser blasting a path through the atmosphere. Edit: and if anyone wants, I'll be happy to run the numbers and prove that. It's not like it's a difficult set of equations or anything. Quote Link to comment Share on other sites More sharing options...
prestidigitator Posted November 3, 2005 Report Share Posted November 3, 2005 Re: A question to the physics-minded... In the timeframe you are talking about, a powerful laser could certainly ionize the air, but I don't think it is likely the air will have the time to evacuate the path of the projectile. As was mentioned, the projectile will also not travel in a straight line so the laser would likely have to be quite wide (greater energy requirements) and the projectile will have to be travelling very quickly to have any kind of range. That or the laser would have to track in front of the projectile and cut a wide swath for the whole trajectory. Now what an ionizing laser is useful for is providing a conductive path through the atmosphere (this is exactly what happens during a lightning strike), so the brief application of a laser could certainly preceed a powerful electrical attack. Supertaser! It can also be used to set up a, "lense," composed of ionized gas for the application of a more damaging laser. Quote Link to comment Share on other sites More sharing options...
tinman Posted November 3, 2005 Author Report Share Posted November 3, 2005 Re: A question to the physics-minded... Ummm... Two words. Projectiles fall. You can never fire a bullet or any other projectile down the path of a laser from the same barrel or even one that is close. There's a reason that your sights on a rifle are sighted to a specific distance. (That's why, by the way, you see laser sights on pistols and not on hunting rifles. For 20 ft the difference is negligible. At 300 yards it is meaningful.) Yeah but for something travelling at those kinds of speeds the drop over even a kilometer would be measured in fractions of inches. Edit: once again Dr. A beats me to the punch Quote Link to comment Share on other sites More sharing options...
tinman Posted November 3, 2005 Author Report Share Posted November 3, 2005 Re: A question to the physics-minded... In the timeframe you are talking about, a powerful laser could certainly ionize the air, but I don't think it is likely the air will have the time to evacuate the path of the projectile. As was mentioned, the projectile will also not travel in a straight line so the laser would likely have to be quite wide (greater energy requirements) and the projectile will have to be travelling very quickly to have any kind of range. That or the laser would have to track in front of the projectile and cut a wide swath for the whole trajectory. Now what an ionizing laser is useful for is providing a conductive path through the atmosphere (this is exactly what happens during a lightning strike), so the brief application of a laser could certainly preceed a powerful electrical attack. Supertaser! It can also be used to set up a, "lense," composed of ionized gas for the application of a more damaging laser. Oooh, I like that last bit a lot! Quote Link to comment Share on other sites More sharing options...
Dr. Anomaly Posted November 3, 2005 Report Share Posted November 3, 2005 Re: A question to the physics-minded... Seeing as how you have ascended beyond the ken of mere mortals, is it possible that by merely erecting a thread that invoked your presence my search was guided by a power greater than Google? No one may know for certain, for this is the realm of faith alone Um..yeah. I mean -- exactly! Of course! There's no other possible explaination!!! ( ) Now what an ionizing laser is useful for is providing a conductive path through the atmosphere (this is exactly what happens during a lightning strike)' date=' so the brief application of a laser could certainly preceed a powerful electrical attack. Supertaser! It can also be used to set up a, "lense," composed of ionized gas for the application of a more damaging laser.[/quote']Aren't there already-working prototypes based on just this principle? Or am I mixing that up with the microwave "pain inducers"? I know they already have working prototypes of those... Quote Link to comment Share on other sites More sharing options...
Dr. Anomaly Posted November 3, 2005 Report Share Posted November 3, 2005 Re: A question to the physics-minded... Edit: once again Dr. A beats me to the punch 5 Curses! Scooped Again!: +5 Lightning Reflexes, for a single action (beating tinman to the 'posting punch') Quote Link to comment Share on other sites More sharing options...
tinman Posted November 3, 2005 Author Report Share Posted November 3, 2005 Re: A question to the physics-minded... 5 Curses! Scooped Again!: +5 Lightning Reflexes' date=' for a single action (beating tinman to the 'posting punch')[/quote'] Quote Link to comment Share on other sites More sharing options...
Dr. Anomaly Posted November 3, 2005 Report Share Posted November 3, 2005 Re: A question to the physics-minded... Sort of like playing 'phone tag', isn't it? Quote Link to comment Share on other sites More sharing options...
tinman Posted November 3, 2005 Author Report Share Posted November 3, 2005 Re: A question to the physics-minded... Sort of like playing 'phone tag'' date=' isn't it? [/quote'] I think I'm going to have to buy an Entangle: 22 Mental Paralysis: 2d6 Entangle (BOECV +1, takes no damage from physical attacks +1/4, works against EGO not STR +1/4, can't form barriers -1/4, OIF: Non-Gaming Discussion -1/2, Gestures: requires both hands -1/2) Quote Link to comment Share on other sites More sharing options...
Dr. Anomaly Posted November 3, 2005 Report Share Posted November 3, 2005 Re: A question to the physics-minded... I think I'm going to have to buy an Entangle: 22 Mental Paralysis: 2d6 Entangle (BOECV +1, takes no damage from physical attacks +1/4, works against EGO not STR +1/4, can't form barriers -1/4, OIF: Non-Gaming Discussion -1/2, Gestures: requires both hands -1/2) Sounds like it's mainly something that would be used on one's self, though. Or maybe the user (who obviously didn't buy Personal Immunity) was in the 'area of effect' when he set it off... Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.