SUNSET: 
Methane Goes Missing on Mars
The Curiosity rover conducted super-sensitive tests of the Red Planet's atmosphere for methane — the most abundant hydrocarbon in the solar system — and found none. What does this finding mean for the search for Martian life?
Deep Impact Meets Its End
Primarily known for its up-close comet observations, the Deep Impact spacecraft went on the fritz in mid-August. The mission team scrambled to reestablish communication, but efforts were unsuccessful.
Asteroid Scheme Still Under Way
Despite funding pushback in the House of Representatives, NASA is full steam ahead in plans for its asteroid retrieval mission.
Hisaki: A New Orbiting Planet-Watcher
Japan's latest spacecraft is designed to study gas escaping from the atmospheres of Earth's neighbors in the solar system.
Onward, Voyager 1, to the Stars!
With the release of new results this week, NASA scientists are now confident that their plucky probe, launched 36 years ago, has entered interstellar space.
Glimpse Into Sun Befuddles Theorists
Scientists sneaked a peek into the Sun’s interior, but what they saw contradicts the assumptions made by models predicting solar activity.
An Annular Eclipse on Mars
Not content merely to record the Martian landscape, a camera on NASA's Curiosity rover recently pointed skyward to watch Phobos cross the face of the Sun.
Sun Loses Lithium with Age
Observations of two solar twins — one old and one young — confirm that the Sun has probably destroyed the fragile element as the star has grown older.
WISE Revived for Asteroid Hunt
NASA officials thought they'd switched off the Wide-field Infrared Survey Explorer for good 2½ years ago. But soon it'll be revived for three years to hunt for small asteroids in Earth's vicinity.
Martian Moon Occults Little Brother
NASA's Mars rover Curiosity watched the larger Martian moon, Phobos, pass right in front of the planet's smaller moon, Deimos.
Comet ISON Spotted Again, Faintly
Comet ISON has been imaged low in the dawn at only 14th magnitude. This suggests a modest showing late this year for the supposed "comet of the century."
Under Stress, Asteroids May Be Fragile
A new microgravity experiment demonstrates the weird, unstable fluidity of asteroid surfaces, with potential consequences for visiting craft.
What Powers the Van Allen Belts?
Thanks to a pair of NASA probes launched last year, space physicists have confirmed that relativistic electrons in the radiation belts surrounding Earth arise from "homegrown" acceleration processes.
The Weakest Solar Cycle in 100 Years
Scientists are struggling to explain the Sun’s bizarre recent behavior. Is it a fluke, or a sign of a deeper trend?
Wave at Saturn (But Will Cassini See You?)
Cassini is taking our picture on Friday, but how much light do we humans actually reflect? We've crunched the numbers, and the answer may surprise you.
A Fix for the "Faint Young Sun"
For 40 years astrobiologists have wrestled with how to make the early Earth warm enough to support life even though the young Sun was at least 30% fainter than it is now. New climate models, powered by supercomputers, are converging on a solution.
The Sun's Heat Wave
Astronomers at the American Astronomical Society's Solar Physics Division meeting discussed new evidence that magnetic waves are the reason our star's corona is blazing hot.
Neptune's Newest Moon
Using Hubble images taken in several patches over a six-year period, astronomers have spotted a tiny object circling Neptune. This find, the first in a decade, brings the planet's moon count to 14.
A Tale of the Sun's Tail
Using observations from NASA's Interstellar Boundary Explorer, space physicists now realize that the solar wind forms a tail that likely extends light-years downwind from the Sun across interstellar space.
Chelyabinsk Mega-meteor: Status Report
The cosmic intruder that exploded in the sky on February 15th dropped thousands of fragments onto the snow-covered plains of south-central Russia. Here's an update on what's been found.
