SUNSET: 
Our "Goldilocks" Solar System
Think our planetary family is normal? Think again. It turns out that the Sun and its retinue formed when the interstellar mix was just right — not too much gas, not too little, and stirred gently for just the right amount of time.
Titan Makes a Splash
It's not covered by a global ocean, as theorists once thought. But Saturn's big moon does sport pools of liquid ethane big enough to float anyone's boat.
An Electrifying Whodunit
Thanks to a quintet of identical spacecraft, space physicists have settled a decades-old debate over what triggers violent electromagnetic substorms inside Earth's magnetosphere.
Earth and Moon Dance for a Far Camera
From more than 30 million miles away, a NASA spacecraft snapped away as the Moon made a graceful pass in front of Earth's colorful disk.
Make Way for Makemake
It took three years to settle on a name for the third-largest object in the Kuiper Belt.
Mars's Ancient Water Works
New observations from a NASA orbiter reveal that water and rock freely mingled across (or under) much of the Red Planet's surface.
Asteroids with Split Personalities
Where did the dozens of known binary asteroids come from? According to a new finding, sunlight alone can force a body to spin in such a frenzy that it literally flies apart.
Water in Moon Dust Raises Questions
Traces of water recently found in glassy granules brought back 40 years ago by the Apollo 15 crew suggest scientists haven't quite figured out yet just how our Moon formed.
SOHO Tallies Its 1500th Comet
The Solar and Heliospheric Observatory has now found more comets than all other comet discoverers put together — not bad for a spacecraft that was designed to study the Sun.
Mercury: The Incredible Shrinking Planet
During its first flyby of Mercury, NASA"s Messenger spacecraft found much less iron on the planet’s surface than expected and a cloud of ionized atoms — including water — caught up in the planet’s magnetosphere. And that’s just for starters.
Martian Dirt is Friendly to Life
The Phoenix lander's first wet chemical analysis of the Martian surface confirms water’s thumbprint and finds the kinds of inorganic minerals you'd have in a backyard garden.
The Two Faces of Mars
Just about the time a Mars-size body creamed Earth with enough force to create the Moon, another big planetoid might have slammed into Mars itself. The result? A two-faced planet and the solar system's largest impact crater.
The Mystery of Saturn’s Double Aurorae
New infrared observations reveal a second auroral ring on Saturn that may help astronomers understand what causes the planet's aurorae in the first place.
Ulysses' Space Odyssey Ends on July 1st
The only space mission ever to study the Sun’s poles directly will turn off at month’s end after a long life of trial and triumph.
Moonlets Perturb Saturn’s Ring
New observations from Cassini show small satellites are responsible for Saturn's F ring looking a little frazzled.
"Holy Cow!" — Phoenix Spots Ice
If the Phoenix lander hadn't been able to find ice on Mars within reach of its robotic arm, NASA scientists would have been majorly bummed. They needn't have worried.
Is Mars Too Salty for Life?
A just-published study, coincidentally appearing as Phoenix prepares to get the dirt on Martian habitability, argues that the Red Planet's soil is at least 10 to 100 times saltier than Earth's oceans.
Amateur Finds Fastest-Spinning Asteroid
While chasing near-Earth asteroid 2008 HJ with a remotely controlled telescope in Australia, Richard Miles made a record-setting discovery.
Jupiter Sports a Third Red Spot
Jupiter's new spot may herald global climate change for the gas giant.
Phoenix's Amazing Photo Finish
Whether by precise planning, good luck, or both, a high-power camera aboard the Mars Reconnaissance Orbiter captured the Phoenix lander during its parachute descent with a menacing crater looming in the background.