Contrary to conventional wisdom, interplanetary and interstellar space is not filled with vacuum, that is, with absolute emptiness. Particles of gas and dust are present in it, remaining after various cosmic catastrophes, they are present in it. These particles form clouds, which in some areas form a medium dense enough for the propagation of sound vibrations, although at frequencies that are not accessible to human perception. So let's find out if we can hear the sounds of space.
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Black hole songs
About 220 million light years from the Sun, in the center, around which many galaxies revolve, is an unusually heavy black hole. It produces the lowest frequency sounds of all. This sound is more than 57 octaves below the middle C, that is, approximately a billion times a million below the frequencies available to the human ear. The discovery was made in 2003 by NASA's orbiting telescope, which discovered in the Perseus cluster the presence of concentric rings of darkness and light, similar to the circles on the surface of a lake from a stone thrown into it. According to astrophysicists, this phenomenon is due to the effect of sound waves of extremely low frequency. The brighter areas correspond to the peaks of the waves in which the interstellar gas is under maximum pressure. Dark rings correspond to "dips", that is, areas of reduced pressure.
Sounds observed visually
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The rotation of heated and magnetized interstellar gas around the black hole is like a whirlpool forming over a sink. As the gas rotates, it forms an electromagnetic field that is powerful enough to accelerate and accelerate on its way to the surface of the black hole to sublight speed. In this case, huge bursts appear (they are called relativistic jets), forcing the gas flow to change direction. This process generates eerie cosmic sounds that spread throughout the Perseus cluster at distances of up to 1 million light years. Since sound can only pass through a medium with a density not lower than a threshold value, after the concentration of gas particles sharply decreases at the border of the cloud in which the Perseus galaxies are located, the propagation of these sounds stops. Thus,these sounds cannot be heard here, on Earth, but they can be seen by observing the processes in the gas cloud. To a first approximation, this is similar to external observation of a transparent but soundproof camera.
Unusual planet
When a powerful earthquake hit northeastern Japan in March 2011 (its magnitude was 9.0), seismic stations across the Earth recorded formations and the passage of waves through the Earth, which caused low-frequency vibrations (sounds) in the atmosphere. The oscillations reached the point where ESA's research vessel "Gravity Field", together with the GOCE satellite, were comparing the level of gravity on the Earth's surface and at an altitude corresponding to low orbits. A satellite located 270 km above the planet's surface recorded these sounds. This was done thanks to the presence of ultra-high sensitivity accelerometers, the main purpose of which is to control the ionic propulsion system designed to ensure the stability of the spacecraft's orbit. Accelerometers 11.03.2011, a vertical displacement was recorded in the rarefied atmosphere surrounding the satellite. In addition, undulating changes in pressure were observed during the propagation of sounds generated by the earthquake.
The motors were commanded to compensate for displacement, which was successfully completed. And in the memory of the on-board computer, information was preserved, in fact, it was a record of infrasound caused by an earthquake. This entry was at first classified, but later it was published by a scientific group led by R. F. Garcia.
The very first sounds of the universe
A long time ago, soon after the formation of our universe, approximately the first 760 million years after the Big Bang, the Universe was a very dense medium and sound vibrations could well propagate in it. At the same time, the first photons of light began their endless journey. Then the environment began to cool, and this process was accompanied by the condensation of atoms from subatomic particles.
Use of light
Ordinary light helps to determine the presence of sound vibrations in outer space. Passing through any medium, sound waves cause oscillatory changes in pressure in it. When compressed, the gas heats up. On a cosmic scale, this process is so powerful that it causes the birth of stars. When expanding, due to a decrease in pressure, the gas is cooled.
Acoustic vibrations passing through the space of the young universe provoked small fluctuations in pressure, which were reflected in its temperature regime. Physicist D. Kramer from the University of Washington (USA), based on changes in the temperature background, reproduced this space music, which was accompanied by the intensive expansion of the universe. After the frequency was increased 1026 times, it became available for perception by the human ear.
So that, although sounds in osmosis do exist, are published and spread, they can be heard only after they have been recorded by other methods, reproduced and subjected to appropriate processing.