Arno Penzias, co-discoverer of the cosmic microwave background, has died age 90

Meant to post this along with submission. The discovery of the cosmic microwave background is one of the pivotal moments in 20th century physics, forming a huge pillar of support for the big bang theory, and providing us with a sort of cosmic laboratory to learn about conditions in the early universe. Its discovery and subsequent study cannot be overstated in terms of impact on our understanding of the universe. Famously, when Penzias and Wilson first discovered it they thought it was noise due to pigeon shit on their telescope. In recent years, the Holmdel Horn telescope where the discovery was made was bought by a developer who had planned to remove it, but a grassroots campaign led to the township purchasing back those three acres with plans for preservation. Here is a nice 7 minute documentary on the scientist and discovery by CUNY, if you are interested.