... Credit: DMR , COBE , NASA , Two-Year Sky Map Explanation: Above is a microwave image of the entire sky. ... After computer processing to remove contributions from nearby objects and the effects of the earth's motion , the map shows temperature variations in the early Universe as red "spots". These spots are the oldest, most distant structures known. ... Publications with keywords: microwave - COBE . Publications with words: microwave - COBE . ... Microwave Hotspots: The Oldest Structures Known ...