SUNSET: 
Why Doesn't Venus Have a Moon?
Back when Earth was an infant, it was pummeled by solar system debris. One blow nearly destroyed it; the debris from that collision coalesced to form the Moon. But how did our neighbor in space, Venus, dodge the same fate? New studies say it didn't.
All Hail Eris and Dysnomia
The bigger-than-Pluto object 2003 UB313 (previously known as Xena) finally has a name. This Kuiper Belt object, which ignited the heated planet-definition debate, will be known as Eris — named for the Greek goddess of strife and discord.
Squeezing Out the Last Drops of Summer
The first-quarter Moon shines near Antares in Scorpius tonight. And as the weekend progresses, you can see the growing Moon slide over to the Teapot pattern of Sagittarius. Be sure to capture these constellations before they are gone for the year.
Find the "Dwarf Planets"
The smoke has cleared. Pluto, Ceres, and 2003 UB313 are officially "dwarf planets." And they are all visible to amateurs tonight — if you have the right equipment. Grab your gear and try some "planet" hunting tonight!
Mars Rovers Hunker Down for Winter
In January 2006 Opportunity imaged these wavy layers within a rock dubbed Overgaard, found near the edge of Erebus Crater in Meridiani Planum. The centimeter-size ripples are festoons — sedimentary features formed when waves lap against a beach.NASA/JPL/Caltech/Cornell Univ. The longevity of NASA's Mars Exploration Rovers, Spirit and Opportunity, is…
Lessons from an Odd Kuiper Belt Object
The shape of 2003 EL61 is at least 1,960 x 1,500 x 1,000 kilometers — making it a fast-rotating squashed football.NASA, ESA, and A. Feild (STScI) To date astronomers have found more than 1,000 Kuiper Belt objects (KBOs) beyond Neptune, and the strangest one of all might just be the…
Stardust's Tiny Treasures
Scientists studying the comet fragments brought home by the Stardust sample-return mission are already scratching their heads trying to understand the things they see.
Peering into Planetary Graveyards
Using the infrared Spitzer Space Telescope to examine the neighborhood around a dead star, astronomers may have glimpsed our solar system’s ultimate fate.
Probing Polaris
Using the Hubble Space Telescope, astronomers have "weighed" the North Star and seen its stellar siblings.
Pluto Adds Two New Moons
Astronomers using the Hubble Space Telescope have found two new moons orbiting the ninth planet. The find makes Pluto the first quadruple Kuiper-belt system.
Mars Polar Lander Still Missing
May's purported discovery of the missing Mars Polar Lander has been disproven with new image of the "crash site."
Sponge Rock
Saturn's odd-shaped moon is making astronomers scratch their heads.
Astronomers Discover "10th Planet"
Astronomers have discovered a distant Kuiper Belt Object larger than Pluto.
A Moon for the "10th Planet"
The largest Kuiper Belt object (KBO) in the solar system, 2003 UB313, isn’t wandering through space alone — it has a moon.
Methane on Mars
Does Mars have life? Recent spectroscopic observations of the Red Planet have found methane, a gas that is predominantly produced by organisms on Earth. This image, which is centered on Valles Marineris, is a mosaic of pictures from NASA's Viking 1 orbiter. Courtesy NASA / USGS. Mars keeps surprising the…
Deep Impact Revisited
This highly processed image of Comet Tempel 1 shows the initial debris after the spacecraft's impactor collided with the nucleus. The ejected dust shrouded the mothership's view of the resulting impact crater.Courtesy NASA / JPL / Caltech / University of Maryland. It has been two months since the Deep Impact…
Spirit Samples Husband Hill
This small section of Spirit's 'Independence Panorama' includes images taken from July 6th to 13th, when the rover was positioned about 100 meters (330 feet) from the summit of Husband Hill.Courtesy NASA / JPL / Caltech / Cornell University. For much of its nearly two-year mission, NASA's Mars Exploration Rover…
The Missing Martian Carbonates
Not a pebble of limestone or other carbonate rock has turned up on Mars, despite loads of water and carbon dioxide on the planet in its history. A NASA reesearcher thinks he knows why.
Astronomers Discover Large Binary Kuiper Belt Object
Two groups of astronomers have discovered a large Kuiper Belt object that has its own little moon.
Deep Impact Makes a Big Splash
Deep Impact successfully slammed its impactor into comet Tempel 1 in the early monring hours of July 4th.
