E-mail updates
Follow on Twitter
Subscribe to RSS
Sebastien Guenneau / Institut Fresnel, CNRS/AMU
This schematic shows that the object in the center of a thermal invisibility cloak stays cold while the heat diffuses elsewheree. The source of the heat is on the left side, maintaining a temperature of 100 degrees Celsius (212 degrees Fahrenheit).
By now, you've heard of "invisibility cloaks" that can hide objects from prying eyes, or military scouts, or sonar scopes — but how about a cloaking device that can keep your computer circuits cool?
That's just the kind of thermal cloaking device that French researchers are proposing in the journal Optics Express, and it might not be too long before it becomes a reality.
"We expect to have the first prototype ready in a few months, since as usual there are a few fabrication constraints which need to be fixed, but nothing really serious," lead researcher Sebastien Guenneau told me in an email. "All seems to be under control."
Most of the invisibility cloaks under development work by using metamaterials to bend light waves or sound waves around a shielded object, making the object undetectable in those wavelengths. Guenneau, who is affiliated with the University of Aix-Marseille and France's Centre National de la Recherche Scientifique, decided to work with his CNRS colleagues to adapt the wave-bending approach to thermal diffusion.
"Our key goal with this research was to control the way heat diffuses in a manner similar to those that have already been achieved for waves ... by using the tools of transformation optics," Guenneau said in a news release issued by the Optical Society, which publishes the open-access Optics Express.
Instead of controlling wave propagation, the thermal cloak would control the flow of heat. "The mathematics and the physics at play are much different," Guenneau explained. "For instance, a wave can travel long distances with little attenuation, whereas temperature usually diffuses over smaller distances."
The basic design of the thermal invisibility shield is similar, however: Rings of specially shaped material guide the heat flow along the desired path.
"We can design a cloak so that heat diffuses around an invisibility region, which is then protected from heat. Or we can force heat to concentrate in a small volume, which will then heat up very rapidly," Guenneau said.
The thermal protection arrangement could be used to channel the heat created by microelectronics away from sensitive areas — an issue that's familiar to owners of the new iPad, for instance. The heat concentrator arrangement, meanwhile, could increase the efficiency of thermal photovoltaic cells or solar thermal power generators.
There are already lots of other methods available for thermal protection — ranging from the plastic-foam insulation used in a cheap beer cooler, to the high-tech aerogel used on NASA's Mars rovers, to the reinforced carbon-carbon panels and protective tiles that were used on the space shuttles. But Guenneau told me that the system he and his colleagues have proposed is "much different" from any existing thermal protection method.
"The flow of heat follows the direction of highest diffusivity, which in our case is around the invisibility zone," he wrote. "Earlier thermal protections require you to basically surround the region to protect with a coating with low diffusivity (e.g., air or polymer, just like your double-glazed windows). To use an analogy with optics, it's just like putting Harry Potter in a box and saying, 'Look, you cannot see Harry anymore, he has been made invisible.' Our approach is to really make Harry invisible, so we should not see the box either."
So what's this cloak going to be made of? In the paper, Guenneau and his colleagues say the materials that go into a concentric multilayered cloak could range from PVC-type polymers to metals such as silver and gold. Production of the prototype cloak is currently under way at the University of Lille, Guenneau said, "but I cannot reveal exactly what it is made of at this stage."
In the next few months, we should be hearing a lot more about the thermal invisibility cloak from Guenneau and his French colleagues ... provided they don't disappear.
More about invisibility:
- Texas scientist creates thermal cloak from nanotubes
- An invisibility cloak for earthquakes? It's possible
- Scientists create 'time cloak' to mask entire event
- Can magnetic invisibility cloak hide weapons?
In addition to Guenneau, the authors of "Transformation Thermodynamics: Cloaking and Concentrating Heat Flux" include Claude Amra and Denis Veynante.
Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.
Leave a Comment:
State of the art Therm-optic camouflage is just a decade away, awesome!
But can it deflect a tachyon pulse? Answer me that!!
No way...the only thing is an invert tachyon pulse...however it very dangerous as we need to be carefull not cause anti-time erruption...
Be careful not to cross the streams.
I've crossed the steams and all it did was get pee everywhere. I was just kid and we were just experimenting and I don't think it makes me gay or anything. Not that there's any thing wrong with that...
Sounds like I'd better run out and buy that new Thermos I need before they get REALLY expensive!
If, any of this is true, they should try to use it to protect the liner used to contain fusion.
That's some forward thinking right there. We desperately need good minds like yours to get us out of the Coal-Oil-NatGas rut.
Would it work? Maybe it'll take bigger, stronger guide rings; the science is beyond me. "Cloaked-liner fusion plant" sounds ridiculously awesome though.
Most of the containment methods for fusion use magnetic fields, not an actual physical liner. I wonder what the temperature limit on these things is?
Brokinarrow, I'm sure it falls way, way, way short of the 10 million degrees minimum needed for fusion. While they are called meta-materials they are still constructed from ordinary materials. I believe carbon is the most thermally stable material that exists. Tungsten has the highest melting point for non-alloyed metals and is just over 6000 degrees F.
Brian - yeah, exactly what I was thinking. Magnetic fields are probably about the only way to go for fusion containment.
invisibility cloak! so cool.... soon the world will look so empty until you bump into the next guy :P
oh my! all i can say is Yippy!! now how much will it cost?
If this stuff works for temperatures in the atmospheric reentry range, coating our space ships and rockets with it could make them extremely reusable, cutting the cost of space travel down exponentially...
The space shuttle thermal protective system was already extremely cost-effective and most of the tiles were actually reusable. No need to go reinventing the wheel on that aspect of space travel.
Besides, re-entry thermal protection accounts for a miniscule fraction of the cost of orbital space travel. The vast majority of the cost of putting anything in to orbit comes from fuel. It takes a lot of energy to get big payloads off the ground and up to orbital velocity.
Chris - Actually most of the cost from putting something in orbit comes from having to build a new rocket each and every time. Fuel is expensive, yes, but not nearly as much as the rest of the rocket. Having an entirely re-usable rocket would drop space entry prices dramatically.
Is that why they cancelled the shuttle program and are returning to basically a one use paradigm? I'm not a rocketry engineer but I think it's got a lot to do with the weight ratio. A reusable system like the shuttle has to consist of quite a lot of extra weight to make up the gliding body which returns. This, of course requires additional fuel to lift all that mass and subsequently limits the range. I'm not sure, but I believe it would have been impossible for the shuttle to reach the moon unless they strapped on another massive external fuel tank and a couple more solid fuel boosters to compensate for the added mass of that extra fuel. In other words, at a certain point aren't you mostly adding more fuel to create lift to launch the mass of more fuel... and that's why the Saturn V had to be as big as it was? Add to that the mass of a returning glider and the whole shootin' match just gets that much bigger...
The shuttles weren't nearly reusable as you would think. They basically had to strip it down and rebuild the engines every time it came back in, not to mention build a giant fuel tank each time as well. That's where a lot of the cost of the shuttle program comes from.
Space X has hopes to make their rockets fully reusable down the road. Elon Musk states in this article the cost of the fuel for the rocket itself is only around $200,000.
http://www.space.com/13140-spacex-private-reusable-rocket-elon-musk.html
Nice video. Cool soundtrack. I hope those buggers have a REALLY good robotic guidance system to get 'em to land successfully! Also, would this type of system be capable of completely leaving earth's gravity well, or only getting to low earth orbit as depicted? As I was trying to illustrate above, the higher you want to fly, the more fuel it takes and so the more thrust to launch, etc...
I suppose they could ferry the pieces and the fuel up to the station and assemble a Mars mission ship in orbit, as has been sometimes suggested in various sci-fi scenarios. I don't know if this is genuinely a realistic plan or not. It would seem to me that the space station necessary to accomplish such a thing would have to be a heckuva lot bigger than the one we're operating now.
I dunno... I don't mean to sound pessimistic, but, maybe in a hundred years?
Is this nothing more than a few layers of heat shields? I don't think the article did a good job of explaining anything except to create a "oooh, aaah" moment with some big, scientific words.
Just because you didn't understand the big scientific words doesn't mean the tech being outlined isn't significant...
Let me try to explain the idea for you though:
In normal heat dissipation devices that we use today, we have some material that will absorb heat from the part we are trying to cool. The heat then moves through that material and is let off somewhere else by the design of the cooling system.
The problem there is that 100% of the heat is not being drawn off.
With these new thermal cloaking materials, the heat flows around the object as if it's not even there. Can you grasp the significance of that?
So then, what about body heat? What is your body going to heat up for the fact being that heat can't move out of the cloak? Only around it, so if the cloak was wrapped around someone, how does their body heat escaped, it can't for the mere reason from what you just said, the heat flows around the object. In this case the body heat with flow on the inside just around and around heating the man or women up.
Chris - obviously you wouldn't wear a thermal cloak, you would put it on machines and computers and such....
Will it cool my processor or video card?
Predator does not approve of this.
Everyone knows you can defeat Predator's heat vision with some simple mud.
It is very interesting and promising tech no doubt, but I don't see how this will help when the object/item you want to protect from heat is the direct source of the heat itself, such as a gpu.
ummm thats Cpu not Gpu yeesh.
gpu = graphics processing unit. n00b
There is no such thing as a free lunch. The heat must go somewhere. Heat pumps have been used for meny years. If one spot is cooled, another gets hotter.
You can move heat around in your ipad, but it has to come out somewhere. So it cam eliminate hotspots by spreading out heat, but then they can do that now if they wanted to spend a few cents to do it.
Well if the hardware were replaced with digital versions then there would be no heat.
Yeah, 'cause digital processing doesn't need electricity and doesn't generate any heat. Riiight.
Morlack, do you even understand the difference between digital and analog? The vast majority of the circuits in a computer are digital. And you might want to look up the three laws of thermodynamics. There is no free lunch.
Sweet, just another thing for criminals to use to steal or kill, or have Big Brother spy on its citizens... They are already talking about using drones over the U.S. to spy on its citizens, now we are going to have invisible FEDS too?
Did you even read the article?
And I have yet to see any invisible cloak!
Interesting choice of words.
Forget the Cloak of Invisibility, I want a Portable Hole.
This is just BS for computer circuits. What good is it to protect your circuit from external heat, the issue with circuitry is to remove the heat generated internally!
Right, removing the internal heat isn't too hard to do, it's keeping that heat AWAY from the part that usually leads to overheating. Although I don't remember seeing it in the article, I would think that you could basically make these things so they're a one-way barrier... heat can get out from behind them, but now back in.
Yeah, and as I mention below, this only works for the radiant portion of a heat load.
okay, Make sure we get an update in a couple of french months there alan....this is at least worth keeping an eye on.
Kind of cool (no pun) but this is only going to work for radiated heat (infrared waves). It's not going to do anything for conducted or convected heat which are a large portion of any heat load. Not to mention that a reflective surface can do the same and probably at a much cheaper price. We've know for a long time how to block radiation without going to extreme of meta-materials.