SUNSET: 
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.
Watch the Moon Pass Mars
A beautiful crescent Moon passes Mars shortly after sunset this weekend. But make sure you find the right spot to skygaze, or you might not see it.
Kepler Hits Planet Bonanza?
Kepler observations have revealed several thousand potential planetary transits. The results are preliminary, but if they hold up there could be more than 200 habitable planets in the mix.
Planets Around Tau Ceti? Not So Fast.
News media have pounced on the recent announcement of a five-planet system around Tau Ceti, a nearby Sun-like star. But is the hubbub merited?
Hubble Takes Galaxy Census
New observations by the Hubble Space Telescope reveal some of the earliest galaxies in the universe.
Big River on Titan
The Cassini spacecraft has spotted what could be the longest river system seen beyond Earth. The river looks like it's feeding into a sea on Saturn's moon Titan.
