Galaxy Cluster Gas Creates Hole in Microwave Background

https://www.nasa.gov/news/releases/latest/index.html

Why would this cluster of galaxy punch a hole in the cosmic microwave background (CMB)? Why would this cluster of galaxy punch a hole in the cosmic microwave background (CMB)?


Source: Astronomy Picture of the Day
Galaxy Cluster Gas Creates Hole in Microwave Background
Astronomy Picture of the Day