Galaxies

The stars in the nearby Segue 1 dwarf galaxy have fewer metals than any other galaxy known, suggesting the object is a relic from the baby universe
 

Gas from another galaxy is hitting our own, triggering the birth of bright new stars and adding fresh luster to the Milky Way

Do yourself a favor. Don't read this article just yet--first, take a moment to zoom around this incredible panorama of our galaxy and soak in the splendor: http://www.spitzer.caltech.edu/glimpse360/aladin.

A curved signature in the cosmic microwave background light provides proof of inflation and spacetime ripples
 

A giant black hole may have hurled a star cluster toward us at record speed
 

The half-the-speed-of-light spin of a giant black hole suggests it grew by digesting another black hole in a galaxy merger. Clara Moskowitz reports 

The bonanza in spotting Pluto's peers nears its end

Small galaxies orbiting the Milky Way may have arrived via dark matter superhighways stretching across the universe

A trove of 715 planets—all members of multiworld systems—joins the list of Kepler's finds
 

The Hubble Telescope's new set of Frontier Fields images includes a galaxy some 13-billion light-years away, which makes it a candidate for the most distant object ever seen. Clara Moskowitz reports 

A disagreement between observations of galaxy clusters and the cosmic background radiation could be explained by the existence of a fourth type of neutrino
 

A puzzle from the big bang's echo is solved using the technique of gravitational lensing