US boffins create darkest material ever
Blacker than a black cat in a coal cellar
US researchers announced yesterday they'd concocted the darkest material on the planet - a carbon nanotube substance so black it absorbs more than 99.9 per cent of light, Reuters reports.
In fact, the stuff's so unrelentingly black it's "30 times darker than a carbon substance used by the US National Institute of Standards and Technology as the current benchmark of blackness" and, with a total reflective index of just 0.045 per cent, is over three times blacker than the nickel-phosphorus alloy which currently holds the world's darkest material record.
The new black was created by researchers at Rice University in Houston in conjunction with a team from Rensselaer Polytechnic Institute in Troy, New York. It's made of carbon nanotubes, standing on end "much like a patch of grass". The tubes absorb some of the light falling on them, while the gaps between the "blades" capture the rest. The material's surface is also irregular, to cut reflection.
Pulickel Ajayan, head of the Rice University team, said: "All the light that goes in is basically absorbed. It is almost pushing the limit of how much light can be absorbed into one material."
The researchers have tested the material in visible light, and will now look at how it handles the infrared and ultraviolet spectrums, as well as wavelengths used in communications systems. Ajayan noted: "If you could make materials that would block these radiations, it could have serious applications for stealth and defense."
Civilian uses for the material might include solar energy conversion, infrared detection, or astronomical observation, Ajayan added.
The team is currently seeking a world's darkest material designation by Guinness World Records. If granted, it will complement Ajayan's 2006 Guinness World Record as "co-inventor of the smallest brush in the world".
The research will be published in the upcoming issue of the journal Nano Letters. ®
Cue obligatory Spinal Tap quote. As the band's Nigel Tufnel said: "It's like, how much more black could this be? And the answer is... none. None more black."
getting my coat already...
awaits a label on this new stuff that says "also available in black"...
Miscellaneous bits of black
A few random points, relevant to some of the earlier comments:
Current stealth technology depends mainly on the geometry of the aircraft: the surfaces are so angled that hardly any of them reflect back any part of a radar beam. Hence the weird non-aerodynamic shape of stealth fighters and bombers, and the need to have a computer to fly them, since they won't glide.
The radar signature of the average stealth aircraft is the size of an eagle's eye, not the whole eagle (a selling point strongly pushed by the Lockheed Skunkworks during development).
Lockheed nicked the basic idea from a technical paper published by a Soviet scientist who did the maths back in the 1950s (or early on, anyway) before computers were adequate to the job of keeping such a thing airborne.
If you change the geometry, you lose your invisibility. During the first Gulf War, a stealth pilot reported that his bomb bay jammed open, whereupon he was lit up like a Christmas tree and saw a radar-guided missile homing in on him. Fortunately, his bomb bay doors unjammed in the nick of time, and the missile careered off (muttering "Where'd he go?", presumably). Ultra-black paint would avoid the geometry problem, but you would then be faced with keeping it clean, since muck would clog the pores on the paint and make it reflective.
Regarding seeing a non-reflective object as a hole in the background: that is why stealth ships were not developed. The concept was tried, but there is significant radar reflection from waves at sea, and a stealth ship shows up nicely as a ship-shaped black hole in the radar background.
Furry cars were tried back in the 1970s (not sure of the precise date). The intention was novelty, not invisibility. They were covered with a special paint that used electrostatic charge to raise "hairs" on the surface after being sprayed on, giving a matt finish. The effect was disappointing. A car body is designed so that it reflects attractive highlights. Remove the reflection, and the result is just dull. Add to that the fact that the "hairs" wore off in patches. I saw one once, and it looked like a mangy beetle. (In fact, it was a Beetle.) Furry cars were a seven-day wonder. So much for civilian artistic uses.
Whoever said it would be good for the anarchist flag is forgetting that said flag is black and red. If you want pure black flags or shirts, join a slightly different party.
Paris Hilton since she looks better sprayed gold than matt black all over.
> What would an object with a total reflective index of 0 look like? Would you be able to see it?
No, but you'd probably notice where it wasn't visible...