"Music of the Spheres" is a phrase used by Pythagaros (ca.580-500BC),an early Greek mathematician and astronomer who was the first to discover a mathematical relationship in the frequencies of the various tones of the musical scales.
Material I could gather from various sources on Pythagaros and his contribution to music,and particularly ,celestial music:-
"Pythagaros and his followers believed that a Universal philosophy could be founded in numbers.According to him there were three forms of music:Music of instruments,music of human body and soul and Music of the Spheres (music of the cosmos).He was the first to establish the theory of strings as a tool for understanding the Universe.
When Pythagaros listened to a blacksmith's hammers pounding iron and producing a variety of reverbrations,he derived musical notes from the same.He analysed the hammers and realised that those that were harmonious with each other had a simple mathematical relationship-their masses were simple ratios or fractions of each other.That is to say that hammers half,two-thirds or three quarters the weight of a particular hammer would all generate harmonious sounds.He explained that if two strings in the same degree of tension were divided,one of them exactly in half,and when plucked,the pitch of the shorter string is exactly one octave higher than the longer string.He also discovered that if the length of the 2 strings in relation to each other are 2:3,the difference in pitch is called a fifth.He also taught that various musical notes had different effects on human beings and could also be used in healing people suffering from ailments.
In Astronomy Pythagaros taught that the Earth was a sphere at the centre of the Universe.He observed that the orbit of the moon was inclined to the equator of the earth.He taught that movements of planets travelling through the Universe created sounds that could be perceived by only those who were trained to hear them(this is the same anaahatha shabda that could be perceived only by yogis of high order at a very advanced stage of yoga).This music of the spheres could be replicated using a single string instrument called the monochord. The monochord was used for demonstration by Pythagaros to explain musical intervals and harmonics to his students."
Marsilio Ficino,(1433-1499),a humanist philosopher and astrologer observed that there was an essential congruity between the music of the spheres and the music of the human microcosm.When a person's soul is in tune with the Heavens it responds just as sensitively to the music of the spheres.
John Milton(1608-1674),the english poet said in his lyric poem"Arcades",Milton's genius of the Wood explains to an assembly of nymphs and shepherds how he listens to the music of the spheres at the end of the day."But else in deep of night,when drowsiness hath locked up mortal sense,then I listen to the celestial harmony."
Kircher ,a 17th century German Jesuit scholar said,"Tune the enneachord of my soul to Thy Divine will;play upon all the strings of my soul to the praise and glory of Thy name that I love Thee!"