SUNSET: 
Starry, Starry, Starry Night
Two astronomers report that small, dim red-dwarf stars are far more abundant in elliptical galaxies than thought — so much so that the total number of stars in the universe is likely three times higher than previous estimates.
Why is the Milky Way Blowing Bubbles?
Using gamma-ray eyes on NASA's Fermi spacecraft, astronomers now see that our home galaxy sports a matched pair of enormous and recently formed bubbles. It's a mystery how and why they formed.
Black-Hole Bonanza
Astronomers announce supermassive double holes, an intermediate-mass hole that seems to have pulled apart a star, fast-spinning holes, and a screaming runaway.
A Glowing Vision of the Early Universe
Astronomers shed new light on our picture of the early Universe.
Black-Hole Missing Link Found?
Astronomers are searching galaxies with no central bulges for intermediate-mass black holes — the missing links between the small black holes that result from collapsing stars and the monsters in the cores of bulge galaxies. A team reports that it's found one — or maybe three.
A Now-You-See-It, Now-You-Don’t Quasar?
Poring over sky-survey data, a Dutch schoolteacher noticed a starless blue-green blob near a faint galaxy. Astronomers think "Hanny's Voorwerp" is a cloud of intergalactic gas lit by an active galactic nucleus (AGN) hidden in the galaxy just to its north. But if so, why don't we see the AGN?
Why You Missed the Supernova in M82
Radio astronomers have spotted emission from a supernova that went unnoticed when it exploded more than a year ago in the nearby galaxy M82.
Dark Matter or Pulsars? Fermi is on the Case
Something funny is going on within a few hundred light-years of us, creating high-energy electrons that we don't understand. Recent data from NASA’s Fermi Gamma-ray Space Telescope keep the mystery alive.
Black Holes First, Galaxies Second
Back when the universe was young, a new study finds, galaxies grew their central black holes faster than the holes' starry surroundings. But how?
Star-Studded Black Holes
A pair of Scottish astronomers has solved the mystery of how young stars can form improbably close to the supermassive black hole at the center of our galaxy.
Weighing Black Holes with a Thermometer
Astronomers use the 12-million-kelvin-blaze of a galaxy's central region to measure its supermassive black hole.
"The Antennae" Fall Into Line
A spectacular pair of colliding galaxies starts to make better sense.
Examining the Throat of a Black-Hole Jet
How do black holes squirt away jets of matter at nearly the speed of light? Now we know!
Hubble's Colliding Galaxies
No two galaxy collisions are alike, as shown in 59 weird images just released by the Hubble Heritage Project.
A Superfast Star from Far, Far Away
The latest "hypervelocity star" that astronomers are puzzling over didn't even start in our own galaxy.
Monster Black Holes Soon to Collide?
The members of a binary black hole in Cancer, one of which is unbelievably massive, look to be on a collision course.
Astronomers Find Double Einstein Ring
A unique example of gravitational lensing in the universe gives clues to the distribution of dark matter in galaxies.
Stars in the Middle of Nowhere
Astronomers have found several young star clusters that don't belong to any particular galaxy.
A Gamma-Ray Burst Out of Nowhere
Astronomers are mystified by a gamma-ray burst without a host galaxy.
Rain of Super-Particles
A 45-year mystery solved? Scientists using the new Pierre Auger Observatory say they've finally tracked down where ultra-high-energy cosmic rays — "tennis ball particles" — are coming from.
