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Programmable Magnets
Martin Hellman writes "A few weeks ago Popular Mechanics awarded one of its Breakthrough Awards for the invention of 'programmable magnets.' Instead of having a single North or South pole, these clever devices have an array of North and South poles. If a matching device with exactly the same array is aligned with the first one, they will experience strong repulsion, just like two single North poles do when brought near one another. If the matching device has the complementary array (North and South interchanged), with correct alignment the two devices will attract. But a slight misalignment will cancel most of the force. Other configurations are possible as well, allowing frictionless magnetic gears and exploding toys. The inventor, Larry Fullerton, used techniques similar to those from CDMA modulation. (Watch the intro video for a brief explanation. While I don't understand magnetism that well, I do understand CDMA and carrying over those ideas to magnetic arrays does make sense to me.)"
Effing magnets - how do they work?
I don't think so. I think huge magnets will increase the mass of the spacecraft needlessly - and you'll still be using around the same amount of energy which you could use if you use fuel or whatever. Unless of course we put a ton of magnets around the solar system and we launch spacecraft in a manner similar to railguns.
I can finally complete my perpetual motion machine!
Before becoming the standard critical slashdotter, I'd like to start positive: I think it's really cool - I believe that, as the video says, there are many applications for these magnets.
The youtube video is worth the time too...
That said, I wonder if the magnets are stable in time. some of the applications described do not allow for failures after a few months/years.
Hope that the costs of the magnets will drop soon too...
Sounds like a research goal in Alpha Centauri. I am pleased.
Weren't those called firecrackers and fireworks?
Or are we talking more like filling a bag with hydrogen and throwing matches at it?
Mit der Dummheit kämpfen Götter selbst vergebens
A decade or so back, I created something called "Super Magnet", and the whole idea was to create a system of atoms/magnets with completely customizable forces - a bit like an infinitely extendable version of what Nature does.
Yes, I know this is in software, but the results can be pretty cool:
http://www.youtube.com/watch?v=LTW09McfCjA
http://www.youtube.com/watch?v=jdfSWsTBtyE
http://www.skytopia.com/project/magnet/magnet.html
Bear in mind these animations are about 10 years old - modern hardware and algorithms would use many more magnets (though creativity counts for quite a bit too).
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Having objects, linear or otherwise, with a differing array of N/S, or plusses and minusses, that can attract or repel allows one to create objects that can interact in ways similar to proteins that fold - objects will be able to configure or reconfigure in very interesting ways.
And we can see it in our space, without microscopes, and play with them.
I've already created this, but in reverse; I have a spaceship with two magnets; one weaker one in the nose cone, and one stronger one that hangs out in front of the ship on a pole and a string. The stronger magnet pulls the weaker one up toward it, generating lift, which moves the rocket through space. Limitless free propulsion!
Impressive, but how do the modified magnets handle the constant stress of other magnetic fields? Magnets naturally have a general north/south pole because that's the tendency of magnetism. Aren't these magnets likely to "wear off" sooner? Used as gears, wouldn't the exertion of magnetic-kinetic force tear up the "programmed" array of magnetic fields? As gears I'm skeptical they could even be reliable without being staggeringly large. You'd never have to worry about stripped teeth but the weight of the gears is an important factor in energy transference.
"Most people, I think, don't even know what a rootkit is, so why should they care about it?"
Wake me up when they invent magnets with east and west poles.
The "frictionless" magnetic gear shown will still have friction in the bearing. The magnetic "teeth" will introduce a huge amount of backlash into the gear system. And you would run into problems if you tried to stack gears beside each other in a gearbox. The high pull-off force/low twist-and-pull force application is neat though. One limitation is that rare earth magnets tend to be brittle, and make a mess when they break.
To be clear though, magnets have been made with multiple poles for a long time, for example those flexible fridge magnets will often have alternating poles across their surface. Also, the pull off application is in many ways similar to the "switchable magnetic bases" . In these devices, the orientation of the magnetic is changed to force the field lines to go through the surface underneath, or to be contained within the base. The innovation in the present work is the use of coding theory to design the patterns.
The main pattern shown in the video is stronger than standard NIB magnets at close range. But die out quickly with distance. That makes them much safer to handle. The strongest NIB magnets could seriously injure you.
I'm curious though about how the pattern used affects how they attract ferrous objects. My hope would be that it has a very similar effect with ferrous objects as with the corresponding magnet, namely that it has greater attraction at short range, but dies out quickly with distance. That also seems logical based on my understanding of induced magnetic dipoles, but I'm no magnetism expert. If so, this also helps to mitigate the other main danger of powerful magnets. (Flying paperclips, etc)
The pattern they show also has minimal net force if one of the magnets is rotated out of alignment, and provides relatively small resistance to such rotation. That has lots of obvious uses for quick- connect quick-disconnect cables, especially those that need to need to withstand high normal forces, but not rotational forces. I'm not clear how the magnets they show handle shearing forces, but either way would have uses for various connectors.
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Railguns are nice, and would work for materials that could stand the strain of a Super-G acceleration.
Sadly, most people don't fit into that category.
I know! How about a maglev loop and a high mountain?
Evacuate most of the atmosphere from a track built as giant loop of pipe with a tail, something like the figure 6 (or 9, in Australia :^), except very, very large. Point the tail up the side of a tall mountain. Magnetically suspend the craft in the pipe, accelerate past escape velocity at a rate of 1-2Gs, then send it "up the tail" into space.
Possible? Could be!
Safe? Who knows!
Fun? You bet!
The acceleration from speeding up in the loop wouldn't be the only acceleration in the system. A circular track would create centripetal acceleration as well. If I remember physics correctly, the radius of the loop is given by R = v^2 / a. If v is the escape velocity (11.2 km/s) and a is 20 m/s^2 (about 2G), we get a loop with a radius of 6272 kilometers.
Then again, I'm no physicist, so feel free to correct me.
Or, combining the two ideas (and having more fun with the less realistic scale), have a ton of magnets around the solar system to form a maglev loop! You can start near the sun, then spiral out as you get faster, and then you have essentially a railgun (as the tail of the 6) to aim you out of the solar system.
Of course, we could probably just do the railgun the size of the solar system... when it's that large, you don't need to accelerate very quickly, since you have plenty of time to get to top speed. Also, then we could totally declare war on Alpha Centauri.
Hey Tri ...
Please reply to posts you are actually talking about.
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