about the satellite images
These two maps are all-sky, false-colour maps of the cold microwave background radiation. They are called false-colour maps because the colours are added to tell the difference in temperatures. The colours are not observable colours. These two images were taken by two different NASA satellites. COBE (COsmic Background Explorer) and the WMAP. (Wilkinson Microwave Anisotropy Probe) These satellites were designed to measure the CMB left over from the big bang. As you can see, the WMAP image has more detail, but both images are actually very similar... The image captured by the WMAP confirmed data that was gathered from the COBE. Both images show the CMB radiation, which is mostly in green, however the colours represent slight variations in temperature. Blue is cooler, and yellow-red is warmer.