SUNSET: 
Ring Around a Saturn Moon?
During a close flyby of Saturn's largest icy moon in late 2005, several instruments aboard Cassini sensed (but didn't actually "see") what appears to be a trio of thin rings and a dust disk surrounding Rhea.
Four Martian Landslides Caught in the Act
A scarp along the edge of the Martian north polar cap is more active than anyone expected.
Of Planets and Palace Elephants
A fourth-grader from Montana bested 800 other contestants to find a new way to remember all 11 major and dwarf planets.
A Triple Asteroid Threat
After taking aim at a passing asteroid with the Arecibo telescope's powerful radar, astronomers discovered that it has two satellites.
Mercury's "Better Half"
When it swept by the innermost planet on January 14th, NASA's Messenger spacecraft showed us a side of Mercury never before seen. After two weeks of intensive study, mission scientists have shared some of the flyby's intriguing results — including views of a "spidery" crater that has them stumped.
A Stardust-Free Comet
When NASA sent a spacecraft to grab samples of a comet and return them to Earth, scientists had high hopes that they'd finally be able to decipher how the solar system formed. Boy, were they wrong!
Mercury, Messenger, and Observers
As the first images are released from Messenger's flyby of the innermost planet, previous ground-based observations are proving to be surprisingly accurate.
A Bird's-Eye View of the Sun
What's it like to coast high over our star? The European-built spacecraft Ulysses is doing that right now — for its third and likely final time.
Reunion with Mercury
For the first time in nearly 33 years, mission controllers have guided a spacecraft past Mercury, a fire-and-ice world that may hold many keys to the solar system's formation.
Mars Dodges a Bullet
Fortified with two months of telescopic tracking, dynamicists say there's now virtually no chance that a small asteroid will strike Mars later this month.
Martian Crater Named for “Chick” Capen
A crater on Mars has been officially named for the American scientist Charles F. Capen.
A New Cycle is Dawning
It's nothing more than an inconspicuous blemish in the Sun's northern hemisphere, but a new sunspot has heralded the start of the next 11-year-long cycle of solar activity.
Cassini's Popularity Contest
After a month-long contest, the Cassini Imaging Central Laboratory for Operations (CICLOPS) has announced which images of Saturn are fan favorites.
Odds of Mars Strike Now 1-in-25
Astronomers have been watching a small asteroid that, they now say, has a 4% chance of colliding with Mars on January 30th.
Mars in the Crosshairs?
Astronomers are waiting to see what becomes of a skyscraper-size asteroid that has a 1-in-75 chance of hitting Mars in late January.
Tunguska's Blast: Less is More
Aided by high-def supercomputer simulations, two researchers now argue that small asteroids striking Earth — like what happened over Siberia in 1908 — may pose greater danger than previously believed.
David Levy's Binary Asteroid
An otherwise run-of-the-mill, main-belt asteroid named 3673 Levy just got a lot more interesting: It has a tiny moon!
Deep Impact's New Assignments
Put to sleep after its smash success in 2005, one of NASA's interplanetary craft is getting a chance to search for extrasolar Earths and to visit a second comet.
Earth's Magnetosphere: On the Ropes
A constellation of five identical orbiting probes has detected skirmishes with the solar wind along Earth's magnetospheric front lines.
Saturn's Sci-Fi Moons
Just when you thought you'd seen everything the ringed planet has to offer, the Cassini orbiter glimpses bizarre little moons shaped like flying saucers.
