Galaxy clusters are large clouds of hot gas, seemingly-ideal places to observe gas cooling and condensing into stars. Yet, we don't see that happening. Here's a look at how black holes and turbulence are conspiring to keep galaxy clusters underpopulated with hot new stars.
Astronomers have detected a mysterious signal 240 million light years away from Earth, in the Perseus Cluster (top), one of the most massive objects in the Universe. The unidentified signal is a "spike of intensity at a very specific wavelength of X-ray light." Scientists don't know yet what is the origin.
Oh, pop art. Lately we've seen Communist war memorials turned into superheroes and Batman and Superman channeling Michelangelo. Now Italian sculptor Giuseppe Veneziano (who previously put supes in compromising positions) has clownified Antonio Canova's 19th century sculpture Perseus and the Head of Medusa in Venice.