Re: Blacker than Black

RB-W:
By making them _more_ efficient emitters of infra-red?
If they were purely passive and produced no waste heat, perhaps...

FTA:
"The reflectance tests showed that our team had extended by 50 times
the range of the materials absorption capabilities. Though other
researchers are reporting near-perfect absorption levels mainly in the
ultraviolet and visible, our material is darn near perfect across
multiple wavelength bands, from the ultraviolet to the far infrared,"
Hagopian said. "No one else has achieved this milestone yet."
In particular, the team found that the material absorbs 99.5 percent
of the light in the ultraviolet and visible, dipping to 98 percent in
the longer or far-infrared bands. "The advantage over other materials
is that our material is from 10 to 100 times more absorbent, depending
on the specific wavelength band," Hagopian said.

TB: That was the part that had my attention.
FTA the reprise:
Black materials also serve another important function on spacecraft
instruments, particularly infrared-sensing instruments, added Goddard
engineer Jim Tuttle. The blacker the material, the more heat it
radiates away. In other words, super-black materials, like the carbon
nanotube coating, can be used on devices that remove heat from
instruments and radiate it away to deep space. This cools the
instruments to lower temperatures, where they are more sensitive to
faint signals.

TB: Admittedly, I'm confused now. It is 98% absorptive in infra-red,
but it also radiates away more heat... I can't quite reconcile this in
my head.

I was imagining that there was some way to use the absorptive effect
to such up active signals such as radar or lidar (and not give a
bounce back). On the heat front, I thought perhaps it could be used
somehow to direct heat output where you wanted it or absorb it
(admittedly, since I can't reconcile highly absorptive and highly
radiative, the how is fuzzy to me... ).

Tom
--
Only solitary men know the full joys of friendship. Others have their
family; but to a solitary and an exile, his friends are everything.
-- Willa Cather (1873 - 1947)Solitudinem fecerunt, pacem appelunt
-- Publius Cornelius Tacitus (from the book Agricola, attributed to a
speech from Calgacus)