SUNSET: 
Universe's Lithium Problem A Bit Better
Studies of primitive stars suggest the universe has far too little of one form of lithium and far too much of another. But new work shows that the second problem might be nonexistent.
Surprise Variable Stars
Astronomers have discovered an unexpected class of variable stars in the open cluster NGC 3766. The stars are problematic for current theories of star behavior and raise perplexing questions about why the stars are variable at all.
Chance to Catch Closest Exoplanet?
In 2014 and 2016, Proxima Centauri will pass in front of two distant stars, potentially revealing details about itself and whether it hosts any planets in the process.
The Mysterious Seven
Seven clouds of hydrogen dotting the space between two iconic galaxies might be crumbs from a past encounter or evidence for the elusive cosmic web theorized to fuel galaxy growth.
Herschel Breathes Its Last
After nearly four years of successful observing, the largest infrared space telescope ever launched has run out of cryogenic coolant, permanently ending its science operations.
Weighing in on Einstein's Gravity
A massive neutron star and its lightweight sidekick provide a unique space laboratory to test general relativity. So far, gravity keeps behaving as it's supposed to.
How to Build a Galaxy
The iconic disk galaxy is perhaps the most common type of galaxy in the universe. But how did these galaxies form their wide, thin skirts and fat, round centers?
Homing in on Dark Matter
Three potential detections from deep underground could be from dark matter particles. While still uncertain, the result suggests a particle mass in keeping with hints from several other experiments.
The Most Distant Star Ever Seen?
Astronomers have detected what might be the farthest star ever spectroscopically observed. The bright object blazes in an unusual location, too, perhaps giving insight into star formation in unconventional environments.
Planck: Best Map Yet of Cosmic Creation
Planck mission scientists have released the first half of their observations of the cosmic microwave background. The results are a stunning confirmation of today's standard model for how the universe formed and grew. But they also raise some head-scratchers.
Habitable Oasis on Mars?
The results from the Curiosity rover's first rock-drilling are in: the rock formed in the presence of fairly neutral, not-too-salty water and has a chemical makeup that might have provided energy for microorganisms.
Mysterious Crab Nebula Flare
Once thought to be a stable source in the sky, the Crab Nebula has erupted in a gamma-ray flare. One of about a half dozen detected since 2007, the flare is ongoing and perplexes astronomers, who still wonder how it's created.
Black Hole Caught Spinning?
X-ray observations of a distant supermassive black hole might end a decades-long debate over the nature of these X-ray signals. But not everyone’s convinced that the observations are what they appear to be.
Info on Russian Meteor Pours In
The fireball that exploded over Russia on February 15th left more than a million square feet of damaged windows, bringing home how fragile life on Earth can be. Here's what S&T's staff has managed to piece together about what happened.
Culprit Pegged for Cosmic Rays
Astronomers working with the Fermi Gamma-ray Space Telescope say they might finally have the “smoking gun” they’ve needed to convict supernova remnants as the origin of energetic particles called cosmic rays.
Earth-Size Planets Common, But Are They Habitable?
The best place to look for nearby Earth-size planets might be the smallest, coolest stars — but these stars could also be bad for creating Earth-like planets.
Pulsar Twitches Perplex Astronomers
New X-ray and radio observations detected a strange switcheroo in the radiation from a pulsar. The repeated hiccups have left scientists scratching their heads.
Astronomers Zoom in on Solar Hairs
New observations with a rocket-launched imager reveal individual strands of plasma wound around each other in the Sun’s corona. These strands could be tied to the mysteriously high temperature of this region.
Galactic Bubbles Spark Debate
New microwave and radio observations resurrect controversy over gigantic lobes seen ballooning from the Milky Way’s center.
Floating Ice on Titan?
Astronomers had thought that ice on the Saturnian moon's methane-ethane seas would sink. But a new study suggests that, if the right conditions are met, ice could actually float on this alien-Earth world.