# Cosmic Microwave Background [[Arno Penzias]] and [[Robert Woodrow Wilson]] were using the Holmdel Horn Antenna to try to do satellite communication experiments but noticed persistent noise in their measurements. Eventually they got in touch with theorists who pointed out this was predicted. [[Serendipity]] [Web URL for this note](http://notes.benjaminreinhardt.com/Cosmic+Microwave+Background) [Comment on this note](http://via.hypothes.is/http://notes.benjaminreinhardt.com/Cosmic+Microwave+Background)