SUNSET: 
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.
The Record Stellar-Mass Black Hole
In a nearby galaxy, astronomers find the biggest-ever small black hole.
Refining Hipparcos's Star Distances
To extract even better star distances, a Cambridge astronomer who took part in the Hipparcos mission has just completed a whole new analysis of the raw data.
New Stars in a Galaxy's Wake
More than 200 million light-years away, a galaxy is shedding gas as it moves. Surprisingly, stars have popped up in the material left behind.
A Galaxy with the Wrong Shape
A newly discovered dwarf galaxy in Hercules isn't like the millions of other "dwarf spheroidals" known in the universe. It's cigar shaped.
Finding the Missing Dwarf Galaxies
Minigalaxies of dark matter ought to be everywhere, says the best theory of how the universe came to be. Now they're finally being found.
A Starry Chemical Imbalance
New high-resolution images of dwarf galaxy IC 10 in Cassiopeia may help resolve an enduring mystery about this star-forming powerhouse.
Bright Galaxies You Can't See
Astronomers have found massive, luminous infrared galaxies 12 billion light-years away. It's not at all clear how they got there.
Galaxy Monster Mash
Astronomers using a battery of ground- and space-based telescopes have stumbled upon the most massive galaxy smashup ever seen.