WMAP satellite located at L2 (beyond the moon)
The Cosmic Microwave Background (CMB) appears at the limit of vision - we look back in time to see the cosmic "fireball". A contrast stretched image reveals slight patchiness arising from slight density variations.
Analysis of the power on different scales in the WMAP CMB image shows a remarkable "acoustic" spectrum, with a fundamental and harmonics. The location and strength of these peaks are sensitive to a number of cosmological parameters.