A 2012 study in the Journal of Theoretical Biology found that steady pink noise reduces brain waves, which increases stable sleep. A 2017 study in Frontiers in Human Neuroscience also found a positive link between pink noise and deep sleep.
Brown noise is hurricane-force wind.
below Fibonacci c. A.D. 1200, 8 billion, not 6.5, fractals, and the Golden Ratio
It's just the twenty-first letter, phi, of the Greek alphabet.