This image displays a portion of the South Pole Telescope survey of the cosmic microwave background (CMB) - the radiant light left over from the Big Bang. Points of light mark quasars and gravitationally lensed galaxies. The variations in the image are minute fluctuations in the intensity of the CMB. The fluctuations are caused by differences in the distribution of matter in the early universe at a time only 400,000 years after the Big Bang. The image is effectively a "baby picture" of the universe.
Credit: SPT Collaboration