English: The Cosmic Microwave Background temperature fluctuations from the 7-year Wilkinson Microwave Anisotropy Probe data seen over the full sky. The image is a mollweide projection of the temperature variations over the celestial sphere.The average temperature is 2.725 Kelvin degrees above absolute zero (absolute zero is equivalent to -273.15 ºC or -459 ºF), and the colors represent the tiny temperature fluctuations, as in a weather map. Red regions are warmer and blue regions are colder by about 0.0002 degrees.
This map is the ILC (Internal Linear Combination) map, which attempts to subtract out noise from the galaxy and other sources. The technique is of uncertain reliability, especially on smaller scales [1], so other maps are typically used for detailed scientific analysis