There are questions that seem trivial right up until the moment you start to think about them. The question of alien music is precisely one of those. It sounds like the premise of a science fiction novel, but behind it lies something that has occupied the minds of mathematicians, acousticians, and philosophers for millennia: Is music a universal language of the universe – or is it merely our own, very terrestrial, very human illusion?
Let us begin not in space, but in a much more familiar place – with sound itself.
Sound as Vibration: Where It All Begins
When a guitar string vibrates, it produces a sound of a specific pitch. This pitch is determined by the frequency of vibrations – the number of full cycles per second, which we measure in hertz. The note 'A' above middle C is 440 vibrations per second. The 'A' an octave higher is 880. Exactly double.
This 1:2 ratio is called an octave, and this is where things get truly interesting. Because the octave is not a human agreement. It is an acoustic fact. When two sounds have a frequency ratio of 1:2, they sound so similar that most people perceive them as «the same sound, but higher.»» This happens because the overtones – the secondary frequencies that accompany any real sound – of these two notes largely coincide. The ear literally hears a kinship.
The perfect fifth – a 2:3 ratio – was not invented by humans either. It is the second simplest way to divide an octave, and it sounds stable and harmonious to virtually any human ear, regardless of culture. The perfect fourth is 3:4. The major third is 4:5. The simpler the numbers in the ratio, the more «pleasing»» the consonance seems.
All of this was noted by Pythagoras – or, more accurately, his followers, as history attributes more discoveries to him than one person could possibly make in a lifetime. But the idea holds true: the harmony of sounds is described by simple whole numbers. And this is physics, not aesthetics.
From Physics to a System: How a Scale Is Built
So, we have the octave. Now we must somehow divide the space between one note and its double. But how, exactly?
The Pythagorean system built the scale by successively stacking perfect fifths – the 2:3 ratio. You take a note, go up a fifth, bring it back within the octave, and go up another fifth. After twelve such steps, we almost return to the starting note – but not quite. A small discrepancy emerges, known as the «Pythagorean comma.»» The math doesn't quite add up, and this mismatch haunted musicians and theorists for many centuries.
The solution was found during the Renaissance and finalized by the 18th century: equal temperament. The idea is both simple and elegant. The octave is divided into twelve equal parts – semitones. Each semitone is exactly 21/12 times higher in frequency than the one before it, which is about 1.0595. Twelve of these steps yield exactly 2 – that is, a perfect octave. The math adds up perfectly.
The price of this solution is a minor compromise. The perfect fifth in equal temperament is slightly «impure»»; it deviates a little from the ideal 2:3 ratio. The major third is also slightly off. But in practice, these deviations are so small that the ear barely notices them, and the benefit is clear: one can play in any key, and the instrument does not go «out of tune»» when changing keys.
This is precisely why Bach wrote «The Well-Tempered Clavier»» – a collection of preludes and fugues in all twenty-four keys, as a demonstration of the new system's capabilities. It was not just a musical masterpiece. It was a philosophical and mathematical statement: look how beautifully compromise works.
Twelve Notes – The Only Option?
Here is where the truly interesting part begins. Twelve semitones in an octave are not a mathematical necessity. They are a fortunate choice made by the European musical tradition. Fortunate because twelve provides a good approximation for many «pure»» intervals – that is, those simple, acoustically harmonious ratios.
But other choices could have been made. And indeed, other cultures chose differently.
- Indian classical music uses 22 shrutis – subtle microtonal intervals within an octave. This isn't just «more notes»»; it's a different philosophy of sound, where each micro-interval carries a specific emotional and spiritual meaning.
- Arabic and Persian musical systems divide the octave into 17 or 24 parts, creating quarter-tones – intervals that, to an unaccustomed European ear, sound «out of tune»», though they are in fact mathematically precise and culturally rich.
- In the 20th century, theorists experimented with systems of 19, 31, or even 53 notes per octave. Some of these provide a more accurate approximation of «pure»» intervals than our familiar twelve.
A mathematician would say: the optimal number of notes in an octave depends on which intervals you consider important and how accurately you want to approximate them. There is no single correct answer. There are different compromises.
And this is where we come to our extraterrestrial guest.
What They Hear – If They Can Hear at All
Let us imagine a being from another planet, endowed with organs of hearing. We must stipulate from the outset: this is already a significant assumption. Hearing is the perception of mechanical waves in a medium. On a planet without an atmosphere, or with one of a completely different composition, sound propagates differently. It's possible that the «ears»» of such a being would perceive a different range of frequencies – lower, higher, or even in the regions we call infrasound or ultrasound.
But let's assume it can hear. Let's assume it lives in a world where sound is part of its sensory experience. In that case, the physics remains the same. The laws of acoustics do not change from planet to planet – they follow from the mathematics of waves, which is universal. The 1:2 ratio will produce «related»» sounds for any being with a sufficiently complex auditory system capable of analyzing overtones. Because that is not a matter of taste, but of physics.
This means that the concept of an octave – or at least something functionally similar to it – would likely arise in any developed musical system. Not because we decided so, but because sound itself is structured that way.
But beyond that, the paths diverge.
The human ear perceives frequencies from about 20 to 20,000 hertz. But this is not just a range. Within it, our hearing is non-uniform: some frequencies seem louder to us at the same physical intensity, while others seem quieter. There are zones of special sensitivity linked to our evolutionary history: we are adept at hearing the sounds of the human voice, a baby's cry, footsteps behind us.
Furthermore, the perception of consonance – what seems «harmonious»» to us – is largely determined by the structure of the cochlea, our auditory organ. Some researchers believe that it is the very geometry of the cochlea that «tunes»» us to perceive simple frequency ratios as pleasant. This is not culture – it is anatomy.
If an alien being's auditory organ is structured differently – for example, if it analyzes sound according to another principle, not by breaking it down into overtones but by perceiving, say, timbre or rhythmic patterns as the primary carrier of information – then its concept of «harmony»» could be entirely different. Perhaps what we would perceive as noise would be consonant to it. And our perfect fifths, a meaningless collection of frequencies.
Here, physics gives way to biology. And biology, unlike physics, will be different on other planets.
Culture as a Third Layer
But even if we assume a similar biology – say, through convergent evolution of the auditory apparatus – culture adds another layer of complexity.
Let's look at Earth. The Japanese musical tradition was long built on the pentatonic scale – five notes per octave. To an ear accustomed to it, it doesn't sound «incomplete»» but rather finished and self-sufficient. Balinese gamelan uses the slendro system – five notes distributed almost evenly across the octave, but not coinciding with our familiar semitones. Moreover, in different villages in Bali, the instruments are tuned slightly differently: a single «correct»» tuning does not exist, and this is considered the norm, not a mistake.
What does this tell us about aliens? Even if their physics and biology of hearing are similar to ours, their history, their aesthetic values, their way of organizing social life through sound – all of this would shape a musical system that might be mathematically related to ours, but culturally entirely foreign.
Imagine a being for whom rhythm is primary, and pitch is secondary. Or one that perceives silence as the fundamental musical element, and sound as its interruption. The Japanese composer Toru Takemitsu, influenced by both Western tradition and the Zen Buddhist aesthetic of the pause, once remarked that for him, silence is not the absence of music, but a part of it. Now multiply that idea by billions of years of different evolution.
Mathematics as a Possible Universal Language
And yet – let us return to mathematics, because it holds a special status in this conversation.
Mathematics, unlike culture, lays claim to universality. If sentient beings on another planet discover prime numbers, they will arrive at the same conclusions we have. If they develop geometry, they will derive the Pythagorean theorem. Mathematics is not the language of humans. It is the language of structures.
If these beings discover that a 1:2 frequency ratio creates acoustic similarity – and they will discover it, if they have hearing and begin to experiment with sound – they might call the phenomenon something else. But they will arrive at the same concept that we call the octave.
This is reminiscent of the argument sometimes used in discussions about the possibility of contact with extraterrestrial intelligence: mathematics is the sole candidate for the role of a universal language. Not because we decided so, but because it describes structures that are independent of who is describing them.
The SETI project – the search for extraterrestrial intelligence – once based its signal detection strategies on this very premise: if an intelligent being wants to announce its presence, it will use numbers. Prime numbers. Mathematical ratios. Perhaps – even intervals similar to musical ones.
A Hypothetical Scenario: What Would Be Shared
Let's try to bring everything together and imagine what in an alien musical system might coincide with ours – and what most likely would not.
Likely to be shared:
- The concept of a repeating interval – an analog of the octave based on frequency doubling. The physics of waves offers no other option for «acoustically related»» sounds.
- A preference for simple frequency ratios as the basis for «pleasing»» consonances – provided their auditory apparatus analyzes overtones.
- The idea of dividing the interval into steps – because it is a mathematically natural way to organize sonic space.
Likely to be different:
- The number of steps in the «octave»» – twelve is a terrestrial choice, dictated by history and compromise. Other beings might have settled on seven, seventeen, or one hundred and four.
- The emotional semantics of intervals – what we call «sad»» or «triumphant»» is determined by culture, not physics. A minor triad sounds melancholic to an ear raised in the European tradition. To another ear, it might sound neutral or even joyful.
- The role of rhythm and timbre – we build music around pitch. Other beings might consider rhythm or timbre to be the primary structural element, with pitch serving as an embellishment.
- The concept of harmony as simultaneous sound – polyphony, chords, counterpoint – are inventions that appeared in Europe in the Middle Ages and were not, for example, part of most Asian musical traditions of the same era. For aliens, harmony could mean something else entirely.
Music as a Mirror of the Mind
There is a temptation to think of music as something absolute. We say, «music is a universal language»», and we feel it to be a beautiful truth. But perhaps it is a beautiful misconception.
Music is a mirror. It reflects how the mind that created it is structured: its biology, its history, its way of organizing time and space in sound. Our music reflects us. The music of imaginary aliens would reflect them.
But mirrors, for all their differences, work on a single principle – they reflect light. And the mathematics underlying sound is that light, which is perhaps the same throughout the universe. Not the notes themselves. Not the scale. Not the key. But the principle – the ratio, the structure, the numerical relationship between vibrations.
Pythagoras believed that the universe was built on numbers and that the planets, as they revolved, produced the «music of the spheres»» – a harmony inaudible to the human ear but mathematically perfect. He was wrong in the details. But perhaps he was right in his intuition: numbers are what unite us.
If somewhere in the universe there is a being that can hear, that can distinguish pitches and seeks order within them – it will discover what we have discovered. Not the note 'C'. Not the seven notes of the diatonic scale. Not the circle of fifths. But it will discover that there is mathematics in sound. And that mathematics is beautiful.
And from there – from there, each goes its own way. Just as Indian ragas, Arab maqams, Balinese gamelan, and European polyphony did. They are all different answers to the same question posed by the physics of waves. And all of them are music.
