• Introduction
• Basic Principles
• Expansion
• Cosmic Light
• History
• Inflation
• Mapping
• Anisotropy
• Sound Waves
• Music
• Curvature
• Summary

Music of Inflation

Key Concepts

Fundamental mode of sound waves is related to the size -- in the microwave background context, the horizon.

Overtones based on the fundamental mode form a pattern of sound that identifies its origin -- in the cosmological context the ultimate source of perturbations from inflation.

We think that fluctuations may have originated from a period of rapid expansion called inflation. Whether or not this actually happened can be "heard" in the microwave background. The fundamental tone of a musical system is related to its physical size - here the horizon size at last scattering.

There is also a pattern of overtones at integer multiples of the fundamental frequency.

In music, the pattern of overtones helps us distinguish one instrument from another: it is a kind of signature of the instrument that makes the sound. In the same way, the pattern of overtones in the sound spectrum of the microwave background ripples acts as a signature of inflation. Inflation's signatures are that the overtones follow a pure harmonic series with frequency ratios of 1:2:3...