This image of the microwave sky was synthesized using data spanning the range of cosmic background radiation detected by ESA’s Planck satellite. These frequencies, which cannot be seen with the human eye, cover the range of 30 to 857 gigahertz.
The grainy structure of the cosmic microwave background is clearly visible in the high-latitude regions of the map. The tiny temperature fluctuations are the result of the density variations from which the structure of the universe originated.
Image Credit: ESA