Now we can hear the "voices" of two black holes

Now we can hear the voices of two black holes

Recently, NASA released the "rumors" of two black holes, the one at the center of the cluster of galaxies of Perseus and M87 (of which we also have a "photograph", the first ever of a black hole in 2019). There is the idea that there are no sounds in Space, because sound waves cannot be transmitted in a vacuum. And so it is, but it is also true that Space is not empty in an absolute sense: there are means within which waves can be transmitted and can be translated into sounds. Here's how

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What is a black hole A black hole is a region of Space where gravity is so great that not even light can escape. For this reason, nothing is blacker than a black hole, so much so that only with special instruments can we guess its position based on how the stars and gases near a black hole behave. A black hole is born from the death of a star, which collapses on itself and explodes. Except that the matter of that explosion, which even exceeds the mass of our Sun by many times, is trapped in a very small point. This singularity, as it is called, has an immense gravity, which tends to suck up what is around it, drawing a sort of circle, known as the horizon of events.

How is it possible to hear black holes That that can be heard in the video released by NASA is a sonification, that is the translation into sounds (audible by the human being) of astronomical data collected by different instruments for the observation of Space.

The "voice" of the black hole at the center of the cluster of galaxies of Perseus was obtained from the pressure waves that the black hole emits and that cross the hot gas of the galactic cluster, rippling it. Recorded since 2003 by the Chandra X-Ray Observatory, these waves can be associated with notes, but the human being cannot hear them as they are: their frequency must be raised by 57-58 octaves (144-288 quadrillion times higher than the their original frequency, where a quadrillion corresponds to 10 15).

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The "voice" of M87, on the other hand, was obtained by translating Chandra's X-rays, optical light collected by Hubble and radio waves captured by the Atacama Large Millimeter Array into sounds (respectively the top, middle and bottom panels in the image below). As they explain from NASA, the brightest region to the left of the image (which is also the "noisiest") is where the black hole is and the top right structure is a jet of material falling on the black hole. “Sonification scans the image at three levels from left to right, with each wavelength mapped to a different range of audible tones. The radio waves are mapped to the lowest tones, the optical data to the mid tones and the X-rays detected by Chandra on the highest tones ".

Credit: Chandra X Ray Observatory