The Sound Of The Big Bang, by Viviana Garabello

According to some scientific research, today it is possible to state that music has existed since the earliest stages of the universe’s formation. Not only were sound waves already there during the Big Bang explosion, but also some independent studies confirm the pattern of the universe has been influenced by those initial waves (Burnham, 2005). In particular, radio astronomy is the science that recently led to many important new discoveries about the universe. It is a subfield of astronomy that studies the universe through the measurement of radio frequencies. After many years of observations, radio astronomy has become a robust and reliable discipline, with researchers from all around the world and hundreds of instruments spread in many different countries.  Many physical and chemical phenomena can be detected through radio astronomy, in different scales, from the well-known atmosphere to the far away and mysterious quasars, pulsars, masers. Recently, the discovery of the cosmic microwave background radiation (CMB) has been considered evidence for the Big Bang theory (Zorpette, Glenn, 1995).

This truly fascinating discovery of sound waves involved in the Big Bang almost suggests a vision of dancing stars, arranging galaxies in the infinite, black sky. But actually, it is not necessary to imagine this, because it is possible to listen to that sound in reality. In fact, a recorded simulation of that primordial sound is available on the internet for all of us to listen to, and this has been possible thanks to a child’s curiosity (Cramer, 2004).

It was a normal day when John G. Cramer, professor of physics at the University of Washington in Seattle, received an email from Daniel’s mom. They happened to read an article entitled “BOOMERanG and the Sound of the Big Bang,” written by the professor, describing a recording of the sound of the Big Bang, based on temperature measurements, when the universe was 376,000 years old (Cramer, 2004). The 11-year-old child, Daniel, was wondering if that sound recording was available to be heard, since he was about to present a science project at school, with the Big Bang as his topic. Professor Cramer was obliged to say the recording was not available; however, this curiosity moved him to think about how to produce such a recording (Cramer, 2004).

Fascinated by this idea, Professor Cramer started working on it and, through his skilled knowledge of the software Mathematica and some calculations, he was able to convert the cosmic background radiation in a musical file, .wav format. When he first played the recording simulation, his two dogs started to bark with agitation. Then they were suddenly calm again as soon as they realized nothing serious was happening: just a part from the sound of the Big Bang playing in the sub-woofer (Cramer, 2004).

In detail, Professor Cramer had to make some adjustments: “The actual Big Bang frequencies, which had wavelengths that were some fraction of the size of the universe at that time, were far too low in frequency to be audible to humans” (Cramer, 2004). So, he had to boost the original frequencies upward by a huge factor through his dedicated program. To produce the sound, Professor Cramer took data from NASA’s Wilkinson Microwave Anisotropy Probe, and then he had to scale the frequencies 100,000 billion billion times (Chown, 2003). Furthermore, with the purpose of making the recording simulation audible to humans, the multiply peaked frequency spectrum was reduced to a monaural sound wave. According to the analysis, the radiations dropped to 60% intensity before and after the peak itself. Hence, the simulation prepared by Professor Cramer covers in 100 seconds a total period of 760,000 years of evolution of the universe, making it possible to hear the Big Bang sound with the decreasing frequencies (Cramer, 2004).

Basically, the sound of the Big Bang is like a legato sound, starting with a peak in a higher pitch, descending little by little to lower frequencies, like if the expanding universe becomes a bass instrument during the time of the entire radiation emission (Cramer, 2004). Actually, the radiation recording demonstrates that the matter that filled the universe, shortly after the Big Bang, was squeezed and stretched, and the compressed regions were heated, and the rarefied zones were cooled (Chown, 2003). The science writer Marcus Chown defined the Big Bang sound as “more like a deep hum than a bang.” Professor Cramer stated, “The sound is rather like a large jet plane flying 100 feet above your house in the middle of the night” (Chown, 2003), something like chromatically descending a couple of octaves.

Two years before, in a previous article, Professor Cramer wrote that the cosmic background radiation was first detected in 1960 and then measured with increased precision by the Cosmic Background Explorer (COBE) satellite in 1990. The primordial sound waves that were present at the time of the Big Bang produced processes of compression and rarefaction, with some regions being slightly hotter or colder than others (Cramer, 2001). In particular, two other experiments describe how the Big Bang’s vibrations generated and left their imprint on the matter-bound photons. As explained by the science writer Ron Cowen, “Whenever gravity caused matter to compress, the pressure exerted by the trapped photons offered resistance. The tug-of-war between gravity and radiation pressure generated acoustic oscillations” (Cowen, 2001).

In other words, not only does the sound of the universe confirm the Big Bang, but those waves also influenced the clustering of galaxies (Burnham, 2005). This is particularly important because, despite its great popularity, the Big Bang theory presents some contradiction in the observations, related to the inflation field, the dark matter, and the dark energy field. These are three hypothetical entities, not yet scientifically confirmed by evidence (Lerner, 2003). Theorists are working hard to try to confirm their assumptions. For example, with the help of the South Pole Telescope, built to detect, observe, and measure the cosmic microwave radiations, cosmologists have also found light waves scattered off the pulsating matter and aligned into bands of polarized light, in full confirmation of the Big Bang echo (Moyer, 2003).

Furthermore, two different research teams, the Sloan Digital Sky Survey (SDSS) and the 2 Degree Field Galaxy Redshift Survey (2dFGRS), have common findings on microwave radiations, which have been found at the expected location, at about 500 million light-years. Also, they identified the remnant glow of the Big Bang and ripples with sound waves emitted shortly after it. This shows that the concordant picture scientists have of the universe is hanging together extremely well (Burnham, 2005).

Since the beginning of the comic expansion, the pattern of ripples was originally set when the matter started to get distributed in regions because of the quantum effects, as hypothesized by the scientists. The squeezing of this matter, fluctuating and aggregating, due to the gravity influence, generated the oscillations of sound waves, which are comparable to the ringing of a bell (Burnham, 2005). These waves still pervade the universe today as a stretched version of the first ones. Actually, the two research teams, through the examination of 267,000 galaxies’ spacial position, found this pattern “matches the expected distances from the centers to the edges of acoustic ripples that grew as space expanded,” according to SDSS astronomer Daniel Eisenstein of the University of Arizona, Tucson (Burnham, 2005).

Another independent study conducted in Arlington, Virginia, confirmed the association between the Big Bang, the microwave radiation, and the ripples generated just as a musical instrument would produce sound waves of characteristic frequencies. The Cosmic Background Imager (CBI) is a telescope placed in the Acatama Desert of Chile. The extremely sensitive technology has been able to capture higher overtones and find other sound peaks. This confirms the previous theories and the model of the universe in which “photons from the early universe scatter off electrons in hot gas in clusters of galaxies closer to Earth, distorting the cosmic background radiation,” says Max Tegmark, a cosmologist at the University of Pennsylvania in Philadelphia (Seife, 2002).

Hence, those first sound waves that impacted photons have been travelling through the universe all along, carrying important information about the Big Bang and constituting the cosmic microwave background. Based on that, and after Professor Cramer’s first Big Bang sound recording, from Wilkinson Microwave Anisotropy Probe (WMAP) measurements in 2003, a new research team of astronomers has been established with the purpose of getting new measurements through a satellite mission (Cramer, 2013). He writes:

The Planck Collaboration, consisting of about 278 authors from 107 institutions, 17 of which are in the USA, working with the European Space Agency, has designed, constructed, launched, and operated the Planck satellite mission to study the CMB. Planck was launched on May 14, 2009. It masses 1900 kg, cost 0.7 billion Euros, and has collected high resolution data of the CMB over many months of operation.

This impressive team produced excellent results. In three years of data collecting and analysis, the Planck Collaboration has worked to appropriately filter the microwave radiations in order to carefully exclude interferences caused by other radio sources coming from this galaxy, the Milky Way, and from galactic dust. The more accurate angular variations, provided by the Planck satellite measurement system, allowed the scientists to discover that the previous WMAP analysis, made in 2003, was missing a significant high-frequency structure in the cosmic microwave background (Cramer, 2013).

The research has shown convincingly that the universe is flat, its expansion is slower, and it is a bit older than the previous calculation. Data show there is more normal matter, cold dark matter, and less dark energy than what was seen in the WMAP analysis. But the most important result shows certain anomalies regarding the cosmic microwave background, having higher temperatures in the southern hemisphere and colder temperatures in the northern hemisphere of the universe (Cramer, 2013). Even if the reason for such anomaly is basically unknown, the team is formulating a hypothesis that the cold spot could be an enormous vacuum containing almost no stars, galaxies or gas (Cramer, 2013).

This last consideration, curiously, seems to state that where there is no music, there is nothing else. Certainly, the connection between music and the origin of the universe is truly fascinating, especially considering its impact on galaxies’ formation. The idea that the original cosmic creation has a pattern, a musical-mathematical-physical order for all matter and energy distribution, is very interesting because it suggests that existence is not casual. In fact, there is great enthusiasm among researchers at this point. Thanks to the new measurement systems and technologies, they are close to overlapping the results and making valid comparisons among the findings. “This will be particularly fun,” Tegmark said (Seife, 2002).

References

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Chown, M. (2003, Nov). Forget the big bang, tune into the big hum. New Scientist, 180, 16. Retrieved from http://search.proquest.com/docview/200451816?accountid=27927

Cowen, R. (2001, Apr 28). Sounds of the universe confirm big bang. Science News, 159, 261. Retrieved from http://search.proquest.com/docview/197573889?accountid=27927

Cramer, J. G. (2001, 01). BOOMERanG and the sound of the big bang. Analog Science Fiction & Fact, 121, 73-75. Retrieved from http://search.proquest.com/docview/215355509?accountid=27927

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Cramer, J. G. (2013, 10). PLANCK: “BIG BANG SOUND” IN HIGH FIDELITY. Analog Science Fiction & Fact, 133, 51-53. Retrieved from

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Lerner, E. J. (2003). Two world systems revisited: A comparison of plasma cosmology and the big bang. IEEE Transactions on Plasma Science, 31(6), 1268-1275. Retrieved from http://search.proquest.com/docview/195169680?accountid=27927

Moyer, M. (2003, 01). Strangelets in the night... dark matter revelation, big bang confirmation and speed-of-light confusion. Popular Science, 262, 72. Retrieved from http://search.proquest.com/docview/222928020?accountid=27927

Seife, C. (2002). Best big bang pictures show new wrinkles. Science, 296(5573), 1588-9. Retrieved from http://search.proquest.com/docview/213598950?accountid=27927

Zorpette, G. (1995). Radio astronomy: New windows on the universe. IEEE Spectrum, 3(2), 18. Retrieved from http://search.proquest.com/docview/196757355?accountid=2792