SUNSET: 
Building Big Elliptical Galaxies’ Cores
Astronomers are tracking down the seeds that likely grew to become today’s most massive elliptical galaxies.
Distant Black Hole’s Spin Clocked
A new measurement could be the farthest back in time astronomers have ever reached when measuring a black hole’s spin.
Fingerprint from the First Stars
Astronomers might have found a star that was infected by the explosive death of one of the universe’s first stars.
Novae Surprise with Gamma Rays
Astronomers have detected gamma-ray emission from three classical novae, an unexpected discovery that has left them perplexed.
Cosmic Rays Hint at Hotspot
A cluster of detections in the Northern Hemisphere sky might point to a source for the most energetic particles bombarding Earth's atmosphere.
The Planet That is No More
A new analysis confirms that an exoplanet thought to orbit in the habitable zone of the star Gliese 581 actually doesn’t exist.
Rosetta's Comet Sleeps Again
Comet 67P/Churyumov-Gerasimenko only woke briefly before starting another nap, expected on-again-off-again behavior that bodes well for the comet-chasing spacecraft's arrival in August 2014.
Direct Evidence of Big Bang Inflation
Researchers with an experiment based at the South Pole have discovered the long-sought "smoking gun" for inflation. The signal was hidden in polarization patterns in the cosmic microwave background and confirms physicists' audacious theory of how the Big Bang happened.
Black Hole Spins Super Fast
X-ray observations and cosmic coincidence unveil the details of a distant supermassive black hole. The result could be a first step in expanding our understanding of how black holes have beefed themselves up over the last several billion years.
Black Hole Ate Too Much
A stellar-mass black hole in the iconic galaxy M83 seems to have kept eating long after it should have stopped. If true, the discovery could have implications for how much black holes can affect their environments.
Mystery of the Missing Galaxy Clusters
Astronomers have counted up the number of galaxy clusters in the cosmos and found a problem: the number is much lower than they expected. What's going on?
Galaxies Grow By Snacking
Evidence from observations and computer simulations supports a picture of galaxy growth that isn't dominated by the rough-and-tumble crashes of big galaxies. Instead, most of the universe's stellar metropolises appear to feed themselves with nibbles instead of feasts.
Galaxies Trace Early Cosmic History
Astronomers have used the Hubble Space Telescope to peek into the universe's early eras using the light from galaxies that existed several hundred million years after the Big Bang.
Exotic Stellar Trio Includes Pulsar
Imagine a three-star system with two white dwarfs and a wildly spinning, superdense neutron star, all packed within a space no bigger than Earth's orbit.
Plumes on Europa
New Hubble Space Telescope observations provide the best evidence yet that Jupiter's icy moon spits out water vapor from its surface. If real, such plumes could reach more than 100 miles above the little world's surface and rain down an extraterrestrial form of snow.
A Double Black Hole?
Strange emission from a distant galaxy paints an enigmatic picture of what’s happening inside its core. One solution: instead of one supermassive black hole, the galaxy hosts two trapped in a tight dance around each other.
Oddball Pulsar Origin?
A few whirling neutron stars might get their start as very different objects, at least if a new analysis is correct.
Cassiopeia A in 3D
Explore a supernova remnant with this fun interactive simulation, created from detailed space- and ground-based observations in multiple wavelengths.
MAVEN Heads to Mars
NASA's next orbiter has successfully launched and is en route to the Red Planet. When it arrives, it will pry into the secrets of Mars's climate, both past and present, and hopefully reveal how the cold, dry world lost most of its ancient atmosphere.
Black Hole Spews Atoms
Observations reveal ionized metals in the jet shot out by a black hole, long-sought information that will help astronomers understand how these objects create their powerful beams.
