"Nuclear macaroni" in the crust of a neutron star is the toughest that has ever been encountered by humanity on Earth and in space. This conclusion was made by an international group of researchers, simultaneously discovering a new mechanism for the emission of gravitational waves.
The result is presented in a scientific paper published in the journal Physical Review Letters by a group led by Charles Horowitz of Indiana University, Bloomington.
Earlier we talked in detail about what neutron stars are. Let us recall this in a nutshell. A neutron star forms after a supernova explosion. It is an unusually dense object: a cubic centimeter of such a substance weighs hundreds of millions of tons. In the center of a celestial body, under the influence of monstrous pressure, protons and electrons have combined into neutrons, hence the name.
The neutron star is covered with a hard crust. In its lower layer of neutrons and protons (at a shallow depth, the latter are still found), structures of a bizarre shape are created. Many of them resemble certain pasta. As the phys.org resource specifies, scientists call them so: "gnocchi", "spaghetti", "lasagna". The collective name sounds like "nuclear pasta". In general, it must be very uncomfortable for those skilled in the art to work on an empty stomach.
The incredible density of the substance and these formations, which play the role of a kind of reinforcement, must create a material of enormous rigidity. But what are the exact numbers? This is what Horowitz's team found out.
As specified in the same release, scientists have undertaken the largest ever computer simulation of the internal structure of neutron stars. On a typical laptop with one good GPU, this would take 250 years of continuous work. Fortunately, the scientists had a supercomputer at their disposal.
The calculation results showed that the shear modulus of this material is unprecedented 1030 erg per cubic centimeter. This means that it is 10 billion times harder than steel and generally breaks all records for this indicator.
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Moreover, it turned out that neutron stars are capable of emitting sufficiently powerful gravitational waves not only in collisions. The formation of new "nuclear macaroni" also leads to a gravitational surge. True, so far the sensitivity of the existing detectors is insufficient to register a signal of this nature. But engineers are working to improve the performance of both equipment and signal processing methods.
Anatoly Glyantsev
