The accidental discovery may give a key to the understanding of the principles of growth of tubular structures arising in caves and marine thermal springs. And also put an end to the debate about the signs of life in Martian meteorites.
Author of the discovery, David Stone, conducted a standard work on electroplating (metal coating on the surface of metallichcheskih products by electrolytic deposition), and stumbled upon a method of growing tubes, reminiscent of Education, found in caves. Stone, a former sculptor and foundry worker at the factory, just recently went back to school. He decided that he ripped off the work, and almost threw spoiled sample into the dustbin. But these tubes so intrigued by it that he decided to show them some faculty members of the University of Arizona, including physics professor Raymond Goldstein.
According to Goldstein, he was shocked when he saw the tubes. Now Goldstein, along with Stone (he is now the applicant doctoral department of soil, water and ecology of the University of Arizona), find out how these structures are formed. Their paper, "Tubular precipitation and redox gradients on a matrix of potential bubbling" will be published in the edition of the Proceedings of the National Academy of Sciences.
• These tubes are obtained in the laboratory are very similar to those found in hydrothermal vents
Tubular structures found in nature in many different places — from the giant hydrothermal vents on the ocean floor to the surface of iron exposed to strong rust. However, the mechanism of formation of these structures remains a mystery. Stone and Goldstein use setup similar to a standard installation for electroplating. It is a rectangular glass chamber height of 10 centimeters with a positively charged iron anode at the top and a negatively charged cathode at the bottom of the iron. Chamber was filled with a mixture of water, ammonium chloride and iron sulfate, and stirring was included. Electric current decomposes water into hydrogen and oxygen. As expected, tiny hydrogen bubbles collected at the negative electrode becomes large, and coming off from the cathode. But to the surprise of the researchers, after a few tens of minutes of the experiment the electrode was covered with real wood small tubes, which scientists call "zheleznotrubki." To study the growth of "zheleznotrubok," the researchers filmed experiments on video.
As Stone said, video recording, carried out with the help of a high-resolution and high sensitivity, clearly showed that the tubes begin to grow around the bubble. These vesicles have a diameter of not more than 3 millimeters. As the bubble grows, a thin film is formed only on the bottle and then begins to grow apart as the bubble comes off. This film type iron oxide known as a green rust formed when ammonia gas in the bubble is contacted with the iron dissolved in the surrounding fluid. Each time when the bubble breaks away at the cathode of the film is little. And is followed by the formation of the tube. As Goldstein said, the tube — the guiding principle for a bubble and the bubble — a matrix for the tube.
In nature, such structures are formed over hundreds or even thousands of years. But in the laboratory Stone and Goldstein can grow a miniature forest height of 2.5 centimeters in diameter tubes in 3 millimeters in just 1-2 hours. "This is — the control system, which can be studied in the laboratory in a reasonable time scale," — said Goldstein.
A better understanding of the emergence of such tubes will understand the patterns of natural processes in nature. Thus, such tubular structures have been found in some Mars meteorites. As is well known, some researchers have presented this finding as a clear evidence of Martian life in the past. But the discovery of Stone argues that the emergence of such structures living organisms are not needed.