 Cosmic Background Explorer

The Cosmic Background Explorer connected two questions: does the cosmic microwave background follow a Planck spectrum, and how does its temperature vary across the sky? John C. Mather and George F. Smoot shared the 2006 Nobel Prize in Physics for these discoveries.^[ref] The FIRAS and COBE DMR comparisons below explain why measuring spectral shape and measuring angular structure require different information.

The Cosmic Background Explorer (COBE) was a satellite launched by NASA on November 18, 1989, and designed to study the cosmic microwave background radiation (CMBR) of the universe. The primary goals of COBE were to measure the CMBR's temperature and to explore the structure and anisotropies (small variations in temperature) within it.