Tucson, Ariz. The comet Pan-STARRS splits the gap between two cacti on the night of March 14, 2013. (Facebook/Pete Gregoire) Twilight on Tuesday provided the best photo op for the comet called Pan-STARRS. It was visible in the Northern Hemisphere just above the western horizon – right next to the crescent moon. Last Tuesday, Pan-STARRS made its closest approach ever of Earth. It will be visible in the Northern Hemisphere for weeks to come. The comet's name is actually an...

Pluto (center) surrounded by three of its known moons. (NASA) A flotilla of 10 or more tiny undiscovered moons might lurk in Pluto's orbit, complicating a spacecraft's planned flyby of the distant dwarf planet in 2015, new simulations suggest. This preliminary finding could make life even more difficult for the team planning NASA's New Horizons mission, which is slated to take the first-ever up-close look at the Pluto system in July 2015. After Pluto's fifth known moon, a small satellite...

ESA and NASA’s Solar Heliospheric Observatory (SOHO) captured this image of a coronal mass ejection bursting off the leftside of the image at 9:25 p.m. EDT on March 12, 2013. This sun itself is obscured in this image. (ESA&NASA/SOHO) An explosion off the sun is speeding towards three NASA spacecraft. NASA says not one, but two, coronal mass ejections (CMEs) went between Tuesday night and early Wednesday morning. Particles from the first CME are headed in the direction of NASA's...

Russian cosmonauts, Pavel Vinogradov (back C), Alexander Misurkin (back L), and US astronaut Christopher Cassidy (back R) put on shoe covers over their space suit boots in front of a mock-up of a Soyuz TMA space craft at the cosmonaut training centre in Star City, outside Moscow on March 5, 2013, before taking their pre-flight exam. The return of several other astronauts from the ISS is being delayed due to bad weather. (Alexander Nemenov/AFP/Getty Images) MOSCOW -- Bad weather is...

In this handout image provided by NASA and released on August 9, 2012, a color image from NASA's Curiosity Rover shows the pebble-covered surface of Mars. (Getty Images/NASA) MOSCOW - Europe and Russia signed a deal on Thursday for a joint Mars mission which will bore beneath the Red Planet's surface for soil samples they hope will solve the mystery of whether there is life beyond Earth. Europe's space agency had hoped to work with NASA on the two-spacecraft ExoMars...

On Sunday evening, revelers can cap their St. Patrick’s Day by enjoying a view of a rendezvous involving two of the brightest objects in the night sky: the moon and the planet Jupiter. (Starry Night Software ) On Sunday evening, revelers can cap their St. Patrick’s Day by enjoying a view of a rendezvous involving two of the brightest objects in the night sky: the moon and the planet Jupiter. About 45 minutes after sunset on Sunday (March 17), the...

This raw, unprocessed image of Rhea was taken on March 9, 2013 and received on Earth March 10, 2013. (NASA/JPL/Space Science Institute) NASA's Cassini spacecraft has snapped its last up-close photos of Saturn's icy moon Rhea, revealing a battered satellite covered in craters from violent impacts. Cassini took the amazing new photos of Rhea on March 9 during its fourth and final planned encounter with the Saturn moon. During the encounter, the probe flew within just 620 miles of Rhea,...

The glowing atmosphere of a strangely giant alien world could help solve mysteries of not just how it formed, but how our own solar system arose, scientists say. The exoplanet discovery comes from the most detailed look yet at the alien planets around the distant star HR 8799, which lies about 130 light-years from Earth. The HR 8799 system is home to four giant planets orbiting a relatively young, 30-million-year-old star, with each planet far larger than any world found...

The aurora borealis, or northern lights, fill the sky early Sunday, March 17, 2013, above the Holy Assumption of the Virgin Mary Russian Orthodox church in Kenai, Alaska. The bright display at times filled the sky. (AP Photo/M. Scott Moon) A massive eruption on the sun Friday at Earth that sparked a geomagnetic storm and boosted aurora displays over the weekend. The sun eruption sent a wave of solar particles streaking toward Earth at about 900 miles per second, according...

The comet that may put on a spectacular light show during a November date with the Sun, was observed by the Deep Impact mission. The spacecraft has also had close fly-bys of comet's Tempel 1 and Hartley 2 and scientific observations of Garradd. (NASA/JPL-Caltech/UMD (Tony Farnham)) Astronomers are already getting set for the arrival of Comet ISON, which may become one of the brightest comets ever seen when it cruises through the inner solar system this fall. NASA has brought...

This mosaic of images from the Curiosity rover's Mast Camera shows Mount Sharp clearer than ever before. (NASA/JPL-Caltech/MSSS) NASA's Mars rover Curiosity has captured a stunningly detailed panorama of the giant Red Planet mountain that is the robot's ultimate science destination. Rover team members assembled the view of Mount Sharp, which rises more than 3 miles into the Martian sky, from dozens of telephoto images Curiosity took last year on Sept. 20. NASA unveiled the image on Friday. (MORE: )...

This image was taken by NASA’s Lunar Reconnaissance Orbiter. It shows a region of the moon before and after the twin Grail spacecraft deliberately crashed into in December 2012. (NASA) LOS ANGELES -- When NASA's twin spacecraft Ebb and Flow crashed into the moon last year, scientists did not count on seeing the aftermath. (WATCH: ) On Tuesday, the space agency released before-and-after pictures of the lunar north pole where Ebb and Flow came to rest. Months after the back-to-back,...