Walter Cronkite was a famous veteran anchorman who worked for CBS News.
On April 10, 1959, the Ghostbusters noticed a black and white TV set next to the main desk and watched Cronkite sign off the evening news. They later walked up to a store front with a television set on the news. Walter Cronkite reported on bizarre ghost sightings from the past hour. Egon Spengler realized that was also how long they were in the 50s and they caused a strain on the space-time continuum. As a result, a hole was torn in the time fabric and ghosts invaded.