An effort to find some of the biggest, most active black holes in the universe provides a better estimate for the ratio of hidden to unhidden behemoths. Multiple NASA telescopes recently helped scientists search the sky for supermassive black holes — those up to billions of times heavier than the Sun. The new survey is unique because it was as likely to find massive black holes that are hidden behind thick clouds of gas and dust as those that are not. Astronomers think that every large galaxy in the universe…
