Scientists at Rice University have created the blackest material created by man, a web of nanotubes made of carbon, and reflect only 0.045 percent of the light back. Four times the capacity of the blackest material ever created, and 100 times the paint on a black Corvette
Pure carbon is one of the blackest substances in nature, but in order to "blacken" it even more, the scientists created a fabric of nanotubes a billionth of a meter long, made of only carbon atoms and arranged vertically. The resulting roughness on the surface is designed to reduce the reflection of light.
The research was published last week in the journal, Nano Letters.
Professor Folickel M. Ajian of the Faculty of Engineering at Rice University, Houston, Texas and the lead of the study, said that the final figures were more dramatic than they expected.
It took more than a year to perform the delicate experiments and prove that only a small fraction of the light is reflected from the surface of the nanotubes, Ajian says,
He also said that now the team has sent a request to enter the Guinness Book of Records about the discovery. The previous record was awarded to the National Physical Laboratory of London whose scientists created in 2003 an alloy surface made of nickel and phosphorus with small craters on it. The material reflected 0.16 percent of the light. The new material is 4 times more efficient and reflects only 0.045 of the light projected onto it.
The theory behind it
According to Wikipedia, a black body is a body that perfectly absorbs electromagnetic radiation at all wavelengths (including light). Any radiation that harms the body does not pass through it or is reflected from it, but is absorbed by it. This ingestion causes a change in the temperature of the black body. And in short - all the light that is projected on it is absorbed by the black body perfectly and is converted from light into heat energy. In reality such a body does not exist.
Theories suggest that the nanotubes may create a super-black object since the dimensions of the tubes can be controlled in the fabric, and experts are only beginning to put these claims to the test.
The new material created by the researchers has several important potential applications. The property of the material to absorb light and convert it into heat can be useful in solar panels and the fact that it does not scatter light is a great advantage for the telescope industry. Additional uses may be reflected in the field of electronics.
Sources
For information on the website physorg.com
For information on the Houston Chronicle website
19 תגובות
The main thing is to deal with really important things
In short, when they say that life is black and white, then black is also a completely relative matter. There is black and there is black
Ha ha ha
Ami,
A black hole must be distinguished from a black body. These are 2 concepts that are syntactically similar but talk about other phenomena in nature.
A black hole is a singular point in space. The black holes in the universe do not swallow everything in their path because they are black. But because they are a curvature of space-time that converges on itself with infinite density.
A perfect black body is the subject of the article. Of course, this is a theoretical object that has not yet been reached, but the experiments are based on this theory.
Liel Petar - I don't think I involve a gender that is not gender.
First, referring to this article, it is a black body that absorbs visible light very efficiently. The above-mentioned body does not absorb X-rays, for example. So, in the substance of the matter, the comment is in place.
Regarding Hawking radiation - I am also familiar with the explanation given in Michael's talkback. The idea I was trying to convey is that of a black body of the luminous type that literally swallows anything that falls into it without returning anything back. Thus it turns out (hypothetically) that even the black body - the blackest there is spectrally - also has something that can escape from it.
A "perfect black body" as you expressed it is a body that will absorb all types of radiation and emit heat (in the ratio of sigma T in the fourth). The article does not refer to such a body.
Greetings friends,
Ami Bachar
The famous B-2 stops being stealthy when it rains. Which certainly reduces its deterrent effect over high precipitation areas.
Two comments:
1. The accepted explanation for Hawking radiation (which - it should be mentioned - is radiation that has not yet been observed and the need for its existence was predicted by Jacob Beckenstein and the mechanism for its creation was proposed by Hawking) is that at the border of the black hole's event horizon (outside it) the buoyant forces separate a particle and an antiparticle that are created in a vacuum anyway Due to the uncertainty effect (which under normal conditions ionizes each other in the blink of an eye), when one of the partners falls into the black hole while the other partner is the radiation.
The phenomenon of tunneling that Yael Petar talked about is another phenomenon that is not related to black holes. It must be remembered that a particle entering a black hole does not stay near the event horizon at all - it continues to fall towards the singularity in the center of the hole. What is commonly called the "size" of the black hole is not similar to what we call the "size" of a normal star. The radius of the hole does not indicate the farthest place from the center where matter is found (as in a normal star) but the place from which nothing (including radiation) can exit. Near the inner side of the "envelope" defined by this radius and known as the "event horizon" there is no material at all.
2. In my opinion, if they ever want to use this "black of black" material in stealth planes it will only be to turn them into baking ovens.
Ami Bachar,
You involve a different species.
1) A perfect black body is an expression that indicates a theoretical ideal in physics, which absorbs all the electromagnetic radiation projected on it (all wavelengths). It heats up and as a result radiation is emitted from it that depends only on its temperature and not on the radiation introduced into it (besides the fact that the initial radiation is the one that heated the body).
Black body radiation (Wikipedia)
2) Hawking radiation - the radiation that comes out of black holes is due to quantum phenomena. In the event horizon on the border of the black hole there is a probability for a quantum particle to be found outside the black hole. Just as if a quantum particle is inside a closed box it has a probability to appear outside the box as well.
Hawking radiation (Wikipedia)
Amir, on the subject of sneaks:
These radar planes are very easy to shoot down...using other stealth or just plain non-stealth missiles.
Energy conservation?
The temperature of the swallowing bone ("the black") rises with swallowing. So there is nothing to worry about conserving energy, it still works.
Question: What about the Law of Conservation of Energy?
Hevrom and friend,
The spectrum relevant to a blackbody is visible light.
No X-rays, no X-rays, and nothing else.
350-750 nm.
There is no such thing as a completely "black body" that absorbs all radiation and emits nothing. Even black holes emit (Hawking radiation).
Greetings friends,
Ami Bachar
Answer to Amri - I read something interesting about a Russian patent for detecting stealth planes, they raise reconnaissance planes to a high altitude that operate a strong radar towards the ground, normally natural returns will be received from the ground, but on the other hand if a stealth plane passes by, the radar operator will see on his monitor "Hor" moved quickly and without reversals, that's how he knew where the plane was.
If this is true and feasible with inexpensive financial means - this means that, as David said, they will be able to create completely stealthy aircraft - radar radiation absorbers as well as cellular panels that can really prevent radiation from leaking into the brain, even though for a perfect performance of blocking radiation to the brain they will have to redesign the cell phone .
And again, it is very critical to know how much 1X1cm of material will cost, to know if it is at all practical.
The material is said to be "true" black in the sense that it absorbs radiation at all wavelengths beautifully.
Does anyone know if and how this type of material can have an effect in the creation of composite materials, for use in stealth aircraft for example?!
Ami
This is not an optical trick.
The light that is reflected = the light that is reflected from every direction around the surface of the tubes. And that's why the inspection of the structure was conducted for a whole year. It's not like they put a photon detector in front of the surface and that's it. In my opinion, it should have been checked from every angle and they did so.
The purpose of the tubes is to trap the light beam, to let the beam be absorbed by as large a carbon surface as possible. It is clear that in the form of tubes the light beam comes in contact with a larger surface than in the case of a smooth surface that is not made of tubes, since the surface area of a hollow tube with a width of 1x1 is greater than the surface area of a two-dimensional square.
And finally, another advantage of the tubes is that the light beam "loses energy" while it hits the sides of the tube a lot.
To Ami Bachner:
They say themselves that the darkening is a result of the structure, but the end result is that a huge part of the energy of the light turns into heat and is not returned anywhere - neither forward nor backward. No one had done it before them.
I apologize, the previous message came without recognition and it is clearly impolite. human mistake.
Greetings friends
I'm not sure, but it seems to me that this is actually a slight physical trick: these tubes apparently redirect the light in the other direction, thus reducing the amount of reflected light. If this is indeed the case, then the substance itself is not "black" in the classical sense of a black body that absorbs all visible light. If this is so, then it is a black body that absorbs part of the light - like other black bodies, with one efficiency or another - and the part of the light that is not absorbed, it emits from the other side, in the direction of the nano flickering.
I know this phenomenon from an oxygen optode that we developed at the Max Planck Institute in Germany. There, in order to reduce the phenomena of quenching and light reflections, we created on the foil of the optode nano-pulses that directed the fluorescent light created as a result of the contact of the oxygen with the reagent and indeed we increased the utilization of the light harvesting in extremely high percentages.
I know of some greens, much blacker than any black substance.