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DateDate: 11-05-2018, 07:12

American physicists and engineers have developed a metamaterial that makes any underwater object "transparent" for sound waves and invisible to sonar. They presented their development at the annual meeting of the American Acoustical Society in Washington, RIA Novosti reported.
"Such materials, when we start talking about them, often seem to be an exclusively abstract idea that can not be translated into practice. On the other hand, mathematics shows that all such properties are real. Now we are creating these materials and trying to understand what opportunities they can provide us, "said Amanda Hanford of the University of Pennsylvania in Philadelphia, USA.
In recent years, scientists have been actively studying the properties of so-called metamaterials - artificial structures from a variety of individual pieces or nanoparticles that can interact with light in an unusual way. Metamaterials, as physicists now believe, will form the backbone of ultra-fast light computers of the future and other futuristic gadgets.
Strictly speaking, metamaterials are not the invention of man - similar to them crystals and structures occur on the wings of many butterflies of "metallic" color, on the shells of many other insects, the wings of birds and even in the famous blue folds on the muzzles of baboon-mandrils.
The experiments of the last ten years show that metamaterials can be tuned in such a way that they begin to interact not only with light and its nearest "cousins" - thermal, x-ray or ultraviolet radiation, but even with magnetic fields, and also generate curious quantum effects that physicists call "time crystals".
As Hanford notes, scientists have already created dozens of similar designs that perfectly reflect or transmit sound waves through themselves, but they all work only in the open air. Acoustic "invisibility caps" working in the water, create much more difficult, since the water is much denser and it does not shrink, unlike air.
American engineers managed to solve this problem by going a little different way - their metamaterial does not let sound waves pass through itself, but reflects them in such a way that the observer seems to be looking at the flat bottom of the sea, river or ocean.
In its structure, it is similar to a pyramid with a height of a meter, covered with a multitude of steel plates with many holes that absorb and transform acoustic vibrations. As scientists believe, the size of this structure and its structure can be easily changed in the future, which will protect objects on the seabed from high-frequency vibrations and hide submarines and bathyscaphes from echolocators.
As previously reported "FACTS," previously a journalist and writer Arkady Babchenko said that Putin's fsbshniki killed Putin's weapons developer, so a breakthrough in the arms industry of this country should not be expected in the near future.