Cosmic microwave background. WMAP (Wilkinson Microwave Anisotropy Probe) spacecraft whole sky image of cosmic microwave background. This map indicates that the age of the universe is around 13.7 billion years and that the universe is expanding at a rate of about 71 kilometres per second per megaparsec (1 Mpc = 3262 light years). The colours represent the varying densities of the early universe as it was about 380,000 years after its formation. The denser regions (red, yellow) formed the seeds of galaxies and other structures. The WMAP sky survey commenced on 11th February 2003. This 5-year WMAP image was produced on 28th February 2008.