For the first time, American physicists have discovered in some meteorites materials that exhibit superconducting properties at ultra-low temperatures typical for space. These substances may be responsible for the formation of magnetic fields in protoplanetary disks and the interstellar medium, scientists write in an article for the scientific journal Proceedings of the National Academy of Sciences.
"Superconductivity in samples of natural matter is an extremely unusual phenomenon. We found deposits of the same types of superconducting materials in two very different meteorites, which suggests that similar substances are often found in asteroids," the researchers write.
Many asteroids and meteorites, as scientists note, were formed at extremely high temperatures and pressures, which have no analogues on Earth. Therefore, they are actively studied not only by astronomers and astrobiologists, but also by physicists. Scientists suggest that substances and various forms of matter, including the so-called quasicrystals, which usually do not exist in nature, can be hidden inside such celestial bodies.
Scientists led by Professor of the University of California at San Diego (USA) Ivan Schuller made an unusual discovery of this kind. They examined fragments of two meteorites, Mandrabilla and GRA 95205, which fell on Australia and the earth's south pole. They belong to different types of meteorites: the first is a rare class of iron meteorites, and the second is an even rarer type of ureilites, stone meteorites with a unique mineralogical composition.
Natural superconductors
Both Mandrabilla and GRA 95205 experienced extreme stress during formation. This prompted scientists to comprehensively study the physical properties of their rocks. To do this, scientists grinded small pieces of these meteorites, after which they performed a series of experiments with them.
When physicists cooled these samples to ultra-low temperatures and began to measure their resistance, they were surprised to find that the current began to move through the crushed meteorites without any obstacles, and their matter began to "repel" magnetic fields, that is, the meteorite substance turned out to be superconducting. Having discovered this phenomenon, scientists tried to find out due to which specific compounds such properties are manifested.
After sifting crushed meteorites and studying their chemical composition, physicists have selected particles with the most characteristic superconducting properties. As it turned out, in both "heavenly stone" they were characteristic of the same compound, which consists of indium, lead and tin. This discovery came as a big surprise to physicists, given the huge difference in the origin of meteorites.
Such superconducting grains, as suggested by Schuller and his colleagues, can be found not only in meteorites, but also in the matter of the interstellar medium, where clouds of gas are formed, from which new stars and planets are born. Their existence, in particular, may explain the presence of mysterious galactic-scale magnetic fields that astronomers recently discovered during observations of the "magnetization" of the Milky Way and other galaxies.