This is it! Scientists have finally found definitive proof of an advanced alien civilization of incredible power! Aliens! We found aliens! Hey, everybody! Aliens!
(Ahem...)
Well, that's what Soviet radio astronomers said back in the early 1960's, anyway. They held a press conference to announce that they had been listening in on an alien civilization that was broadcasting radio signals into space. These signals were of unbelievable power and went up and down in frequency with a period of roughly one hundred days. Nobody had ever seen, or heard, anything like that before. It had to be evidence of intelligent beings with fantastically advanced technology. Maybe they were sending us a signal!
Sadly, that hypothesis turned out to be wrong, and the Soviet radio astronomers probably felt kind of silly after making their announcement. 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!