Detonate the Shields
July 13, 2009 1:41 PM Subscribe
What would spaceship "shields" look like in reality?
This is for a book I'm writing, I'm trying to envision the effects of "shields" if they were a basic electrostatic field. As in "pushing or disrupting" matter as it heads towards the ship, effectively with a stream of electrons. Such a system could repel debris, or if you crank up the wattage repel projectiles fired in anger.
I know it sounds impracticable, but humor me. Would such a powerful and large field make it impossible for ships to active their shields inside a solar system, for fear of burning off the atmospheres of any local planets? What power outputs would be needed to repel 1000 joules of kinetic energy? What would the field LOOK like, would it only be visible when objects come within range of it?
This is for a book I'm writing, I'm trying to envision the effects of "shields" if they were a basic electrostatic field. As in "pushing or disrupting" matter as it heads towards the ship, effectively with a stream of electrons. Such a system could repel debris, or if you crank up the wattage repel projectiles fired in anger.
I know it sounds impracticable, but humor me. Would such a powerful and large field make it impossible for ships to active their shields inside a solar system, for fear of burning off the atmospheres of any local planets? What power outputs would be needed to repel 1000 joules of kinetic energy? What would the field LOOK like, would it only be visible when objects come within range of it?
Yeah, I think a reasonable model might be the magnetic field around the earth.
posted by Freen at 1:56 PM on July 13, 2009
posted by Freen at 1:56 PM on July 13, 2009
...effectively with a stream of electrons.
How do you propose to generate this stream of electrons, without the ship itself building up a large positive charge in short order, which will in turn pull the elctrons back to itself rather than pushing anything outward?
posted by DevilsAdvocate at 2:01 PM on July 13, 2009
How do you propose to generate this stream of electrons, without the ship itself building up a large positive charge in short order, which will in turn pull the elctrons back to itself rather than pushing anything outward?
posted by DevilsAdvocate at 2:01 PM on July 13, 2009
a) Unless you're doing hard sci-fi, it should look and work however you want it to look and work. See dilithium crystals, holodecks, any psudeo-science from your favorite trek episode.
b) Taking a page from reality (earth's shield) something like from this site, specifically this image.
posted by anti social order at 2:02 PM on July 13, 2009
b) Taking a page from reality (earth's shield) something like from this site, specifically this image.
posted by anti social order at 2:02 PM on July 13, 2009
It would probably be invisible but you could add some hokum glow when the field interacts with objects. Since space is full of dust maybe you would see a just barely visible flickering glow and the occasional flash.
My opinion has nothing to do with reality. This disclaimer applies to all my postings actually.
posted by chairface at 2:08 PM on July 13, 2009 [2 favorites]
My opinion has nothing to do with reality. This disclaimer applies to all my postings actually.
posted by chairface at 2:08 PM on July 13, 2009 [2 favorites]
What power outputs would be needed to repel 1000 joules of kinetic energy?
Possibly none at all, if you don't necessarily want to stop the projectile and are satisfied with deflecting it in a different direction, such that its speed remains the same, it just misses your ship. As long as the projectile's speed is constant, it neither gains nor loses kinetic energy as it changes direction.
posted by DevilsAdvocate at 2:08 PM on July 13, 2009
Possibly none at all, if you don't necessarily want to stop the projectile and are satisfied with deflecting it in a different direction, such that its speed remains the same, it just misses your ship. As long as the projectile's speed is constant, it neither gains nor loses kinetic energy as it changes direction.
posted by DevilsAdvocate at 2:08 PM on July 13, 2009
"Well, sir, you can't actually see the shields. Magnetic fields are invisible to the human eye. But the technicians added some phlebotinum to the generators so that they are pink/opalescent/sparkly/electrical. It turns out that the shields caused more trouble than prevented them, when nobody could see them. You wouldn't believe how many repairmen/painters/window-washers walked right into the things and turned into a puff of dust."
posted by cmyk at 2:17 PM on July 13, 2009 [2 favorites]
posted by cmyk at 2:17 PM on July 13, 2009 [2 favorites]
Okay, imagine a magnetic field with the field lines pointing up and down through your desk, and only your desk. If a particle traveling parallel to your desk were to go over your desk, it would have its path curved by the magnetic field. With just the right setup, you can imagine a particle circling endlessly over your desk. (Highly imaginative, I know)
Some of the Mars missions are contemplating doing just what you suggest, a large magnetic field to cause charged matter to curve around the ship. This would not work for uncharged stuff, like gamma rays or neutrons. It would be less effective for big hunks of matter with a small charge. A hunk of rock the size of a grain of sand probably would also be of neutral charge, and still dangerous. It would do nicely for some of the solar wind.
If you want to harden up your SF, maybe have some kind of beam going out from the front of the ship that would ionize the incoming space dust, making it suitable for deflection.
Practically everything is magnetic at some level, but the levels required for uncharged stuff I would call Highly Impractical. Around some very young pulsars (magnetars), the fields are strong enough to just ... strip the water in your body apart. Obviously, you won't be doing that, so I'd stick with the ionization beam. It might require a significant tie-in to the navigation and sensors, as well as a lot of computational juice to have a laser flickering about, stripping electrons off of incoming grains of rock.
posted by adipocere at 2:19 PM on July 13, 2009
Some of the Mars missions are contemplating doing just what you suggest, a large magnetic field to cause charged matter to curve around the ship. This would not work for uncharged stuff, like gamma rays or neutrons. It would be less effective for big hunks of matter with a small charge. A hunk of rock the size of a grain of sand probably would also be of neutral charge, and still dangerous. It would do nicely for some of the solar wind.
If you want to harden up your SF, maybe have some kind of beam going out from the front of the ship that would ionize the incoming space dust, making it suitable for deflection.
Practically everything is magnetic at some level, but the levels required for uncharged stuff I would call Highly Impractical. Around some very young pulsars (magnetars), the fields are strong enough to just ... strip the water in your body apart. Obviously, you won't be doing that, so I'd stick with the ionization beam. It might require a significant tie-in to the navigation and sensors, as well as a lot of computational juice to have a laser flickering about, stripping electrons off of incoming grains of rock.
posted by adipocere at 2:19 PM on July 13, 2009
Yeah, the trouble with most shield as envisioned in sci-fi is that they're monopoles which are sort of impossible in nature. A magnetic field like Earth's can create a sort of bubble that guides charged particles along isoclines but there's still a big hole at the poles and you need a hell of a field to deflect anything bigger than elementary particles.
Gravity is a monopole - gravitational fields only have one point in contrast to electromagnetic fields so accepting some sort of gravitational manipulation is one way to pull it off.
As far as strippng atmospheres off of planets, the solar wind is already a fair amount of constant activity and planets seem to stand up to that OK. You'd need a hell of a field to affect something as massive as a planetary atmosphere to the point where you get into the issue of energy density, that is, how much energy can the ship generate to pull this off. Even if you could generate that mush energy then you get to the issue of conversion efficiency so the ship would have to have a way to dispose of waste heat, etc.
So, to actually answer your question, the best bet is that a magnetic field would make stuff move along an invisible surface that's roughly spherical around the ship, except at the poles where it wouldn't do anything.
One possibility would be for a ship to surround itself with particulate matter during a battle, possibly help in place with an electric or magnetic field. Thus anything you throw at the ship has to get though a few tons of suspended sand first.
posted by GuyZero at 2:19 PM on July 13, 2009
Gravity is a monopole - gravitational fields only have one point in contrast to electromagnetic fields so accepting some sort of gravitational manipulation is one way to pull it off.
As far as strippng atmospheres off of planets, the solar wind is already a fair amount of constant activity and planets seem to stand up to that OK. You'd need a hell of a field to affect something as massive as a planetary atmosphere to the point where you get into the issue of energy density, that is, how much energy can the ship generate to pull this off. Even if you could generate that mush energy then you get to the issue of conversion efficiency so the ship would have to have a way to dispose of waste heat, etc.
So, to actually answer your question, the best bet is that a magnetic field would make stuff move along an invisible surface that's roughly spherical around the ship, except at the poles where it wouldn't do anything.
One possibility would be for a ship to surround itself with particulate matter during a battle, possibly help in place with an electric or magnetic field. Thus anything you throw at the ship has to get though a few tons of suspended sand first.
posted by GuyZero at 2:19 PM on July 13, 2009
An electrical or magnetic field would not be very effective against uncharged objects (like a purely kinetic weapon). A shield that bends space-time so as to be able to deflect uncharged particles would also deflect photons and thus cause the ship to appear distorted or even invisible as light flowed around it. This means the shield doubles as a cloaking device, but on the other hand sensors would be useless.
posted by jedicus at 2:22 PM on July 13, 2009
posted by jedicus at 2:22 PM on July 13, 2009
If you had an electrostatic field, and your "enemy" was shooting plasma (or an ion stream) at you, there would I think be bremsstrahlung (braking radiation). I have no idea what the spectrum would be like, so feel free to make it up and say it just glows. If you had an electrostatic field and the enemy shot a bullet at you, nothing would happen, since bullets are electrically neutral. Same things hold for static magnetic fields.
If your opponent has bullets (or you're looking out for little rocks) and you're shooting a "stream of electrons" it's not static. You might as well aim your ion beam or lasers or whatever. The intensity of the "push" that you apply to the bullet will depend on how fast you need to change its direction. If you had to do it very fast, there would be significant energy deposited, and you might as well say that the little things heat up and glow like cool streaks.
posted by a robot made out of meat at 2:32 PM on July 13, 2009
If your opponent has bullets (or you're looking out for little rocks) and you're shooting a "stream of electrons" it's not static. You might as well aim your ion beam or lasers or whatever. The intensity of the "push" that you apply to the bullet will depend on how fast you need to change its direction. If you had to do it very fast, there would be significant energy deposited, and you might as well say that the little things heat up and glow like cool streaks.
posted by a robot made out of meat at 2:32 PM on July 13, 2009
Yeah, the basic problem with a "magnetic shield" sort of system would be that most macroscopic things are electrically neutral to a very very high degree of approximation. So, for instance, a charge imbalance of around one part in 10^36 would be enough to pull the Earth apart. Neutral things can pass through field lines undeflected, so giant space projectiles of doom would generally have no problem going through a magnetic shield.
I dunno, maybe you can invent some automagical device -- the Charge Imbalancer! -- that, um, gives everything a net charge so it's deflected by your shields. Or something.
Of course, if you have enough energy handy to run the Charge Imbalancer and the Magneto-deflection-shield, you could probably just fire a Death Ray at whatever's coming your way and be done with it.
posted by chalkbored at 2:39 PM on July 13, 2009
I dunno, maybe you can invent some automagical device -- the Charge Imbalancer! -- that, um, gives everything a net charge so it's deflected by your shields. Or something.
Of course, if you have enough energy handy to run the Charge Imbalancer and the Magneto-deflection-shield, you could probably just fire a Death Ray at whatever's coming your way and be done with it.
posted by chalkbored at 2:39 PM on July 13, 2009
A charged particle beam is easy (hell, until a couple years ago, most of us had one on our desk pointed at our head). If you can put a static charge on an incomming projectile and the same charge on your ship, you could deflect quite a projectile. Two point charges (which are impossible) consisting of a mole of electrons each repel one another with like 80 trillion tons of force. This will of course jostle your ship around in depending on the speed and mass of the projectile(s) you're dealing with.
If I'm your enemy I'm going to work real hard at making my projectiles hard to put a static charge on. Better still, I'm going to put a charge on them that is oposite of whatever you're using.
Non-matter based weapons are not going to care much about this.
Personally, I'd just haul some sand around, arrange for there to be a big cloud of it between you and me, and then point and laugh when your nuclear tipped missle of death runs into a grain of sand at an apreciable percentage of the speed of light.
posted by Kid Charlemagne at 2:40 PM on July 13, 2009
If I'm your enemy I'm going to work real hard at making my projectiles hard to put a static charge on. Better still, I'm going to put a charge on them that is oposite of whatever you're using.
Non-matter based weapons are not going to care much about this.
Personally, I'd just haul some sand around, arrange for there to be a big cloud of it between you and me, and then point and laugh when your nuclear tipped missle of death runs into a grain of sand at an apreciable percentage of the speed of light.
posted by Kid Charlemagne at 2:40 PM on July 13, 2009
Jedicus gets my vote - if it's going to stop energy weapons / effects, it's probably going to cloak as well.
That being said, there's a classic memory burned into my brain from the old anime Star Blazers where they manipulate nearby asteroids to band around the ship at a perimeter, protecting it from all sorts of weapons, similar to what GuyZero said. If I remember (and this is going back a loooong time), they used a magnetic field to affect the iron content of the asteroids, which gave them much more cover from attacks than a purely E/M shield would. Of course, this depends on the presence of the asteroids, unless you want to carry your own deploy-able mass (I could see iron ball bearings being used in this manner - deploy them during a fight, recall them when done, easy to make and replace from local supplies.)
This assumes the shields are for combat purposes - if you're looking more for protection against radiation, space dust, etc., you'd need something else. Maybe a charged hull would be more appropriate? Instead of a shield, make the ship itself repel the offending material / energy.
posted by GJSchaller at 2:41 PM on July 13, 2009
That being said, there's a classic memory burned into my brain from the old anime Star Blazers where they manipulate nearby asteroids to band around the ship at a perimeter, protecting it from all sorts of weapons, similar to what GuyZero said. If I remember (and this is going back a loooong time), they used a magnetic field to affect the iron content of the asteroids, which gave them much more cover from attacks than a purely E/M shield would. Of course, this depends on the presence of the asteroids, unless you want to carry your own deploy-able mass (I could see iron ball bearings being used in this manner - deploy them during a fight, recall them when done, easy to make and replace from local supplies.)
This assumes the shields are for combat purposes - if you're looking more for protection against radiation, space dust, etc., you'd need something else. Maybe a charged hull would be more appropriate? Instead of a shield, make the ship itself repel the offending material / energy.
posted by GJSchaller at 2:41 PM on July 13, 2009
Hell, if you've got that much magnetic power, why not go all space-opera and do what they did in the first Lensman book where the badies sucked the iron right out of people's blood.
posted by GuyZero at 2:47 PM on July 13, 2009
posted by GuyZero at 2:47 PM on July 13, 2009
make the ship itself repel the offending material / energy
aka monopole. Darn conservation laws!
posted by GuyZero at 2:48 PM on July 13, 2009
aka monopole. Darn conservation laws!
posted by GuyZero at 2:48 PM on July 13, 2009
But that's not to say you can't just invent monopoles. Niven did for no reason in particular. So if you accept that monopoles exist you can have a ship that repels stuff omnidirectionally. Where stuff is either charged or magnetic. You might be able to repel non-magentic metals via rapidly changing magentic fields that set up eddy currents like they use in recycling stations to separate aluminium cans from plastics.
posted by GuyZero at 2:56 PM on July 13, 2009
posted by GuyZero at 2:56 PM on July 13, 2009
If your spaceship can create artificial gravity inside of it where the people are walking around, why can't it create artificial antigravity outside of it to push interstellar dust and the like away from it?
posted by letourneau at 3:50 PM on July 13, 2009
posted by letourneau at 3:50 PM on July 13, 2009
Workers at a 3M tape plant discovered an static electricity based force field.
The force that engaged him inside the tent was invisible and impenetrable, certainly making him unable to move further forward.
posted by nomisxid at 3:52 PM on July 13, 2009 [1 favorite]
The force that engaged him inside the tent was invisible and impenetrable, certainly making him unable to move further forward.
posted by nomisxid at 3:52 PM on July 13, 2009 [1 favorite]
Well, it would emit the radiation normally given out by by unobtanium when bombarded by bogons
So, a sort of purplish yellow.
posted by lumpenprole at 4:14 PM on July 13, 2009
So, a sort of purplish yellow.
posted by lumpenprole at 4:14 PM on July 13, 2009
Check out Bow shock
You could probably come up with a handwavy way to describe shields as something like bow shock. Plus graphics of it look really impressive.
posted by pseudonick at 4:29 PM on July 13, 2009
You could probably come up with a handwavy way to describe shields as something like bow shock. Plus graphics of it look really impressive.
posted by pseudonick at 4:29 PM on July 13, 2009
People have already talked about the problem with magnetic fields and metal slugs or missiles. There's no force exerted unless the incoming object is charged or magnetic, and you'd need a pretty strong charge at that. Of course, it would look really cool, since magnetic fields exert a force perpendicular to both the field direction and the direction that the object is traveling. You get all sorts of fancy spirals and such out of this.
Electric fields could be better, but again the effect is only repulsive if the incoming object is charged similar to the shield's polarity. By the way, electrical monopoles are all over the place in the form of, well, any charged particle. It's only magnetic monopoles which don't seem to exist. The term monopole has to do with the field shape, namely having field lines that leave (or enter) uniformly in all directions, not possible polarities.
I would think for a shield against physical weapons, the answer is going to come from deflection of some sort. Space is big, all you need to do is push the incoming missile out of the way and it's going fast enough to miss by kilometers. This could happen either by shooting bullets with bullets or small missiles, or by having a laser mesh that you shoot at incoming objects. If you can ionize a small part of it with an extremely high intensity laser, you should be able to deflect incoming objects.
A stream of electrons is a particle beam, which would really just act similarly as my high intensity laser example, and could possibly impart enough momentum to be interesting. It could also charge a metal object for the sake of electromagnetic manipulation, I suppose. Of course, you have to remember about Newton's third law, so if you push hard on something, you are pushed back just as hard. Get very intimate with F = ma.
posted by Schismatic at 5:33 PM on July 13, 2009
Electric fields could be better, but again the effect is only repulsive if the incoming object is charged similar to the shield's polarity. By the way, electrical monopoles are all over the place in the form of, well, any charged particle. It's only magnetic monopoles which don't seem to exist. The term monopole has to do with the field shape, namely having field lines that leave (or enter) uniformly in all directions, not possible polarities.
I would think for a shield against physical weapons, the answer is going to come from deflection of some sort. Space is big, all you need to do is push the incoming missile out of the way and it's going fast enough to miss by kilometers. This could happen either by shooting bullets with bullets or small missiles, or by having a laser mesh that you shoot at incoming objects. If you can ionize a small part of it with an extremely high intensity laser, you should be able to deflect incoming objects.
A stream of electrons is a particle beam, which would really just act similarly as my high intensity laser example, and could possibly impart enough momentum to be interesting. It could also charge a metal object for the sake of electromagnetic manipulation, I suppose. Of course, you have to remember about Newton's third law, so if you push hard on something, you are pushed back just as hard. Get very intimate with F = ma.
posted by Schismatic at 5:33 PM on July 13, 2009
Don't use a shield. Do some kind of space warping thing ("just like gravity"). Then an incoming missile on a straight line continues "straight" in a twisted space that carries it around the ship. Basically, the ship can create a pseudo-mass at any point nearby to deflect things. Then it turns it off. Other planets would feel a gravity wave. It wouldn't have to be very big, depending on the size and speed of the projectile. Asteroid sized mass?
posted by DU at 5:37 PM on July 13, 2009 [1 favorite]
posted by DU at 5:37 PM on July 13, 2009 [1 favorite]
Oh and if you are literally asking what it would LOOK like, it would look like gravitational lensing.
posted by DU at 5:38 PM on July 13, 2009
posted by DU at 5:38 PM on July 13, 2009
The space-warp idea was used in Independence War (I-War), an old space combat sim from 1997.
Unlike the all-emcompassing shields of Star Trek, I-War's system used two projectors, one on the top and one on the bottom of the ship. Incoming projectiles/beams were deflected/absorbed by distorting space immediately in front of the weapon. The drawbacks were limited arcs of coverage (rear aspect was uncovered) and multiple target weaknesses (could only block one direction per projector, so if two ships were firing on you, one would get through). It definitely made combat a more tactical, thinking experience.
posted by Nice Guy Mike at 5:48 PM on July 13, 2009
Unlike the all-emcompassing shields of Star Trek, I-War's system used two projectors, one on the top and one on the bottom of the ship. Incoming projectiles/beams were deflected/absorbed by distorting space immediately in front of the weapon. The drawbacks were limited arcs of coverage (rear aspect was uncovered) and multiple target weaknesses (could only block one direction per projector, so if two ships were firing on you, one would get through). It definitely made combat a more tactical, thinking experience.
posted by Nice Guy Mike at 5:48 PM on July 13, 2009
Shields in sci-fi are extremely 'soft' and shouldn't appear in hard sci-fi stories. The invsible shield is nice because it costs very little special effects money, not because its plausible.
Theyre also cliches like space princesses or invading martians. Try anything different or a big modification like a shield of quicksilver or space-warp shield.
If you interested in real space combat, then check out this earlier question.
posted by damn dirty ape at 7:21 PM on July 13, 2009
Theyre also cliches like space princesses or invading martians. Try anything different or a big modification like a shield of quicksilver or space-warp shield.
If you interested in real space combat, then check out this earlier question.
posted by damn dirty ape at 7:21 PM on July 13, 2009
Seconding and thirding letourneau. So many sci fi universes posit the existence of ubiquitous artificial gravity that is so cheap and so simple that every ship has it, and it still works even when the rest of the ship is powered down or inoperable. Heck, how many times has been powered down/damaged so much that even life support is turned off, yet the artificial gravity plates are still on. Oh, and those gravity plates are really cool, because they only pull in one direction, and simulate the gravity of an infinite plane, not a point at the middle of the ship. And what's even cooler is that those fields are almost always calibrated to stop precisely at the hull of the ship, so you need cool magnetic boots to walk outside. Oops. let me get back on topic: So yeah, if your ships have artificial gravity, they should be able to repel any projectile using applied gravity tech.
posted by mrgoldenbrown at 7:23 PM on July 13, 2009
posted by mrgoldenbrown at 7:23 PM on July 13, 2009
If you interested in real space combat, then check out this earlier question.
Which includes a comment from me raving about I-War and it's forerunner, Warhead. I must sound like a broken record. :-)
posted by Nice Guy Mike at 8:28 PM on July 13, 2009
Which includes a comment from me raving about I-War and it's forerunner, Warhead. I must sound like a broken record. :-)
posted by Nice Guy Mike at 8:28 PM on July 13, 2009
The earth's magnetic field looks nothing like this (linked above). Set aside that the sun-earth distance is about 215 solar radii, rather than about four in the figure. I have no idea whether the size of the magnetic bubble is right. The glowing turquoise lines basically follow the shape of the magnetic field lines, and the shape of the bowshock is right, but neither of these glows in space.
The earth's magnetic field traps charged particles in the van Allen belts because the strong fields near the poles function as a magnetic mirror. The van Allen belts do not glow. Aurorae glow when the charged particles enter the atmosphere; they lose energy by collisions with oxygen and nitrogen molecules in the upper atmosphere, which then emit light as they relax back to the ground state.
Note that a dipole magnetic field, as a shield against charged particles, does not have a "hole" near the poles (as GuyZero says above). The magnetic mirror effect is strongest at the poles. You get aurorae when the magnetic field becomes weak enough that charged particles are "turning" in the atmosphere rather than above it. This happens in a ring around the magnetic poles.
A conducting object moving through a strong magnetic field loses kinetic energy to eddy currents. (Experiment: drop a strong magnet through nonmagnetic metal pipe. Seriously, go do this experiment right now.) Of course a ferromagnetic object is drawn toward the strongest magnetic field, so a purely magnetic shield has an obvious flaw.
An electrostatic field only repels one charge. And electrically polarizable objects are attracted to strong electrostatic fields, just like magnetically polarizable objects are attracted to strong magnetic fields.
A beam of fast electrons is a pretty good destructive weapon (against unmagnetized targets, for the reasons discussed above). But that's an "active shield," like the US's proposed missile defense "shield": you need a character to aim the beam.
posted by fantabulous timewaster at 5:06 AM on July 14, 2009
The earth's magnetic field traps charged particles in the van Allen belts because the strong fields near the poles function as a magnetic mirror. The van Allen belts do not glow. Aurorae glow when the charged particles enter the atmosphere; they lose energy by collisions with oxygen and nitrogen molecules in the upper atmosphere, which then emit light as they relax back to the ground state.
Note that a dipole magnetic field, as a shield against charged particles, does not have a "hole" near the poles (as GuyZero says above). The magnetic mirror effect is strongest at the poles. You get aurorae when the magnetic field becomes weak enough that charged particles are "turning" in the atmosphere rather than above it. This happens in a ring around the magnetic poles.
A conducting object moving through a strong magnetic field loses kinetic energy to eddy currents. (Experiment: drop a strong magnet through nonmagnetic metal pipe. Seriously, go do this experiment right now.) Of course a ferromagnetic object is drawn toward the strongest magnetic field, so a purely magnetic shield has an obvious flaw.
An electrostatic field only repels one charge. And electrically polarizable objects are attracted to strong electrostatic fields, just like magnetically polarizable objects are attracted to strong magnetic fields.
A beam of fast electrons is a pretty good destructive weapon (against unmagnetized targets, for the reasons discussed above). But that's an "active shield," like the US's proposed missile defense "shield": you need a character to aim the beam.
Would such a powerful and large field make it impossible for ships to active their shields inside a solar systemGo to a football field and build a solar system and the answer to this question will leap out at you. The solar system is empty. If the sun doesn't strip atmospheres, neither will your characters.
What power outputs would be needed to repel 1000 joules of kinetic energy?This is the kinetic energy (1/2mv2) of a car (m = 1000 kg) moving at 1.4 m/s, a brisk walk. You can push a car this fast, and perhaps also stop it, with your hands and feet.
posted by fantabulous timewaster at 5:06 AM on July 14, 2009
While a hole may not be the best analogy a simple magnetic dipole has a non-uniform field. You can test this by taking a simple bar magnet and approaching it with a magnetic object from the side vs the end. You'll need a more complex arrangement of dipoles or a changing magnetic field to achieve a uniform field around something like a spaceship.
Also, yes, electrons are electric field monopoles but unless you're going to build up a big charge before you leave it's not very simple to take an otherwise electrically neutral ship and give it a uniform electric charge. You can shuffle electrons around but if you did the logical thing of moving them from the inside of the ship to the surface (or vice-versa) I'm not sure exacty how that would work. Maybe if you moved them out of a Farady cage type setup or something.
posted by GuyZero at 9:04 AM on July 14, 2009
Also, yes, electrons are electric field monopoles but unless you're going to build up a big charge before you leave it's not very simple to take an otherwise electrically neutral ship and give it a uniform electric charge. You can shuffle electrons around but if you did the logical thing of moving them from the inside of the ship to the surface (or vice-versa) I'm not sure exacty how that would work. Maybe if you moved them out of a Farady cage type setup or something.
posted by GuyZero at 9:04 AM on July 14, 2009
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Then again, sometimes energy (rather than matter) being deflected leads to beautiful effects like the Aurora Borealis, so there's that.
posted by explosion at 1:48 PM on July 13, 2009