This sounds like the same futuristic material coating the super-fast spaceship that Zaphod and Ford Prefect were admiring outside Milliways in Hitch Hiker's Guide to the Galaxy.
"The question then becomes, how can it be put to use on Earth, and what benefits could we see on the surface of the planet rather than above it?"
I'm sure there are many applications as an interior coating in optics, such as photography, cinematography, telescopy and microscopy, leading to sharper images. E-Ink displays could use it on the dark side of their "pixels" for higher contrast. Car body paint shops could offer it for the darkest matte black on the block. I could finally have the ultimate set of curtains to ensure cave-like darkness on the brightest day. Ninjas will appreciate it for moving undetected through the shadows (and slightly more commonly with special forces and swat teams, who might also appreciate the coating on their gear). I could get an ultra-black turtleneck to make it look like my disembodied head and hands are animating themselves. My cell phone could be blacker than anyone else's. And finally, this could make for really high-contrast black-light posters.
I don't think that would work. When it absorbs light, it converts that energy into heat, then re-radiates that heat. That re-radiated heat will show up to the infrared motion sensors.
I see one way you might be able to work around this: if you made a suit out of this stuff, and were somehow able to rig it so that all of the heat is dumped inside the suit, then it would be "invisible" to IR sensors. However, it would get really uncomfortable inside that suit really fast.
Also, even if it somehow magically absorbed all of the IR without re-radiating, it would still be possible to build IR sensors that detect it: if it's perfectly black in IR, it will show up as a "shadow" against a warmer background. To be invisible to IR, you need a suit that matches its temperature to the surroundings.
On that note, it sounds like you could make a really good heat ex-changer with this stuff. I wonder if this would make for improvements in fields like refrigeration and energy production.
Infrared is not all the same. For one thing the frequency depends on the temperature.
But more importantly it absorbs infrared light, and converts it to heat. Heat and light are not the same thing! True, hot things emit light, but that doesn't make them the same thing.
Most practically you can cool the device once the energy is heat. Or just dilute it in a heatsink.
Indeed. In fact, if this low albedo extends over such a wide range in wavelength, this material might be as close to the theoretical concept of a "blackbody" we have seen.
[quote]if you made a suit out of this stuff, and were somehow able to rig it so that all of the heat is dumped inside the suit, then it would be "invisible" to IR sensors. However, it would get really uncomfortable inside that suit really fast.[/quote]
That gave me an idea... if it were possible to make a sphere that had this coating on the outside and dumped the heat to the inside, you'd have a great heat source for a Stirling engine. This could work exceptionally well in space if you can use the light-absorbing sphere oriented so that it shaded the cool side of your engine, thus maximizing the temperature difference.
A lot of those potential applications will hinge pretty heavily on what kind of durability this coating demonstrates. What works great on metal may never give rise to a product suitable for fibers. And what works in space may wear away surprisingly quickly under the constant assault of airborne particulates.
All that said, it does provide a convenient justification for "slightly darker black" turtleneck jokes.
During daylight hours, black cars were up to 12 per cent more likely be involved in crashes than white vehicles, while at dawn and dusk, the figure rose to 47 per cent.
There is simply not enough information to say how bad black cars based on that article. If they where significantly safer at night then everything in that article could be true even though black cars where safer overall. Also, because they are using the 'worst case numbers' some makes and or models could be safer when panted black etc. Let alone changes in the type of drivers that chose specific colors. Let alone more complex situations ex: Yellow might be the least safe color for a given driver, but if it's only chosen by safety contentious people due to it's reputation it might have the best record.
Edit: I suspect black cars are moderately less safe, but less than a 10% difference overall otherwise they would just give the actual numbers.
> I could finally have the ultimate set of curtains to ensure cave-like darkness on the brightest day.
BTW, If you really do need this, aluminium foil taped to the windows blocks light completely. It's not a curtain, but if you need it really dark, it works very well.
PV technology, as far as I know, works less efficiently at higher temperatures, so the heat storage might not be desirable. On the other hand, there's also concentrated solar power, which uses giant arrays of mirrors to heat up water for use in a traditional steam turbine, for which this might be useful.
There is photovoltaic, and solar thermal. One uses heat, the other uses electromagnetic light.
This black stuff would help with the solar thermal type - but for a power plant a difference of 1% is completely unimportant, so this will never be used for that unless it's extremely cheap.
Same here on iPhone. This drives me nuts when mobile sites "break" the web. I would rather double tap and scroll than put up with a subpar mobile experience. Now with the iOS 5 reader, I think that mobile sites are mostly irrelevant.
More confusion though: The advantage over other materials is that our material is from 10 to 100 times more absorbent
There's some snake oil there. If their material absorbs 99%, that would mean that other materials would only absorb 1-10%, which is not true. They even say in the article that black paint absorbs 90%.
What they probably mean is that their material reflects 10-100 times less light. Ie, something 90% absorbent is 10% reflective, and their material is 0.1-1% reflective....
"It's so ... black!" said Ford Prefect, "you can hardly make out its shape ... light just seems to fall into it!"Zaphod said nothing. He had simply fallen in love.The blackness of it was so extreme that it was almost impossible to tell how close you were standing to it.
This has been known a while. The earliest paper that I can find describing this phenomenon is from 2009 [1] but I distinctly recall seeing some slides describing R&D results corroborating this at least as far back as 2007.
This is neat stuff in general but sometimes I think people oversell the utility of structured forests of nanomaterials. There are even startups promising the sky based on nanostructured silicon. [2]
The jury is still out on exactly how bad nano-tubes are but the good news is that they are generally too small to block your lungs in the same was a soot particles and too soft to cause any mechanical damage.
Asbestos fibres are much larger and much stronger - it's like comparing steel drill swarf to chocolate flakes!
If you are facing something really cold and black - like space then the blacker your radiator is the more power you can emit at a given temperature.
In theory a perfectly reflective silver object would never cool down and a perfectly black one would cool to -270C however much power you dumped into it
You said: "...would cool to -270C however much power you dumped into it" and that is not true.
And in any case you don't need to be a perfect emitter to be in equilibrium with the temperature of the cold sink, all you need is infinite time, but any emitter, no matter how bad will eventually equilibrize.
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[ 3.5 ms ] story [ 89.2 ms ] threadThis sounds like the same futuristic material coating the super-fast spaceship that Zaphod and Ford Prefect were admiring outside Milliways in Hitch Hiker's Guide to the Galaxy.
It might be used to make a stealthy surface even stealthier though.
I'm sure there are many applications as an interior coating in optics, such as photography, cinematography, telescopy and microscopy, leading to sharper images. E-Ink displays could use it on the dark side of their "pixels" for higher contrast. Car body paint shops could offer it for the darkest matte black on the block. I could finally have the ultimate set of curtains to ensure cave-like darkness on the brightest day. Ninjas will appreciate it for moving undetected through the shadows (and slightly more commonly with special forces and swat teams, who might also appreciate the coating on their gear). I could get an ultra-black turtleneck to make it look like my disembodied head and hands are animating themselves. My cell phone could be blacker than anyone else's. And finally, this could make for really high-contrast black-light posters.
I see one way you might be able to work around this: if you made a suit out of this stuff, and were somehow able to rig it so that all of the heat is dumped inside the suit, then it would be "invisible" to IR sensors. However, it would get really uncomfortable inside that suit really fast.
Also, even if it somehow magically absorbed all of the IR without re-radiating, it would still be possible to build IR sensors that detect it: if it's perfectly black in IR, it will show up as a "shadow" against a warmer background. To be invisible to IR, you need a suit that matches its temperature to the surroundings.
But more importantly it absorbs infrared light, and converts it to heat. Heat and light are not the same thing! True, hot things emit light, but that doesn't make them the same thing.
Most practically you can cool the device once the energy is heat. Or just dilute it in a heatsink.
That gave me an idea... if it were possible to make a sphere that had this coating on the outside and dumped the heat to the inside, you'd have a great heat source for a Stirling engine. This could work exceptionally well in space if you can use the light-absorbing sphere oriented so that it shaded the cool side of your engine, thus maximizing the temperature difference.
All that said, it does provide a convenient justification for "slightly darker black" turtleneck jokes.
This might not be such a good idea when you consider that "black cars are 47 per cent more likely to be involved in road accidents".
Source: http://www.telegraph.co.uk/motoring/news/7845366/Black-cars-...
During daylight hours, black cars were up to 12 per cent more likely be involved in crashes than white vehicles, while at dawn and dusk, the figure rose to 47 per cent.
There is simply not enough information to say how bad black cars based on that article. If they where significantly safer at night then everything in that article could be true even though black cars where safer overall. Also, because they are using the 'worst case numbers' some makes and or models could be safer when panted black etc. Let alone changes in the type of drivers that chose specific colors. Let alone more complex situations ex: Yellow might be the least safe color for a given driver, but if it's only chosen by safety contentious people due to it's reputation it might have the best record.
Edit: I suspect black cars are moderately less safe, but less than a 10% difference overall otherwise they would just give the actual numbers.
BTW, If you really do need this, aluminium foil taped to the windows blocks light completely. It's not a curtain, but if you need it really dark, it works very well.
This black stuff would help with the solar thermal type - but for a power plant a difference of 1% is completely unimportant, so this will never be used for that unless it's extremely cheap.
With more information, more pictures, and less confusion about "absorbing light leading to lower temperatures."
There's some snake oil there. If their material absorbs 99%, that would mean that other materials would only absorb 1-10%, which is not true. They even say in the article that black paint absorbs 90%.
What they probably mean is that their material reflects 10-100 times less light. Ie, something 90% absorbent is 10% reflective, and their material is 0.1-1% reflective....
"It's so ... black!" said Ford Prefect, "you can hardly make out its shape ... light just seems to fall into it!" Zaphod said nothing. He had simply fallen in love. The blackness of it was so extreme that it was almost impossible to tell how close you were standing to it.
This is neat stuff in general but sometimes I think people oversell the utility of structured forests of nanomaterials. There are even startups promising the sky based on nanostructured silicon. [2]
[1] http://www.pnas.org/content/106/15/6044.full
[2] http://www.bandgap.com/contactus.html
Asbestos fibres are much larger and much stronger - it's like comparing steel drill swarf to chocolate flakes!
Can someone with more physics knowledge explain how absorbing more energy will result in reduced temperatures. I would assume the opposite.
In theory a perfectly reflective silver object would never cool down and a perfectly black one would cool to -270C however much power you dumped into it
And a perfectly blank one will absorb light, heat up and also emit blackbody radiation.
A perfect emitter facing an infinite cold sink is in perfect equibirium at the temperature of the cold sink.
You said: "...would cool to -270C however much power you dumped into it" and that is not true.
And in any case you don't need to be a perfect emitter to be in equilibrium with the temperature of the cold sink, all you need is infinite time, but any emitter, no matter how bad will eventually equilibrize.