So what was the mysterious source of radio waves? It was the first quasar ever spotted. The word quasar is short for “quasi stellar radio source.” Quasi stellar just means they look like stars, and radio source means they emit radio waves even ones that pulsate with amazing regularity and make people on Earth think they must be hearing a communication from aliens. Quasars are incredibly dense objects that were formed in the early universe and put out a tremendous amount of energy. In fact, one quasar can emit a hundred times more energy than our entire milky way galaxy!