Galaxies

Resolving how the galaxy's halo of stars was assembled would provide important clues about galactic formation

The black hole at the center of Milky Way could be steadily feeding on a cloud of asteroids, producing frequent, small x-ray flares. John Matson reports

An excerpt from physicist Lawrence M. Krauss's new book explains why we are not the center of the universe

The ambitious Laser Interferometer Space Antenna, a casualty of tightening budgets, could rise again

The current census of middleweight black holes is incomplete in many ways. Additional studies will push astrophysicists' understanding of and search for middleweights in new directions

A new biography of Stephen Hawking by long-time acquaintance Kitty Ferguson explores the famous physicist's life and theories in honor of his 70th birthday

Tipping the scales at less than about a million suns in mass, middleweight black holes may hold clues to how their much larger siblings, and galaxies, first formed

The Milky Way seems to have too few galactic hangers-on, except when it comes to the big ones. What gives?

The supermassive black hole at our galaxy's center may be about to shred and consume a cloud of gas and dust the size of a planet

Galaxies NGC 3842 and NGC 4889 host black holes, each of which about 2,500 times the mass of the one at the center of the Milky Way. John Matson reports

The discovery, of objects 9.7 billion solar masses large or more, suggests there is still much to learn about how monster black holes grow

Books and recommendation from Scientific American