Here is the image of the microwave sky produce by the COBE satellite, showing variations at the %0.001 level in the temperature. The resolution is around 7° , and the central region shows the large "foreground" signal from our own galaxy. The rest is believed to be a cosmic signal from the "edge of the observable universe". Although the resolution is low, these results gave the first ever measurement of the fluctuations on the largest scales. When these were combined with data on galaxy clustering from surveys such as the APM survey, models of the origin of the fluctuations were pinned down on a wide range of scales, and many were ruled out. (Image from NASA)