NASA's Solar Dynamics Observatory (SDO) satellite captures an image of the Earth's moon crossing in front of the Sun, on May 3, 2011. (NASA/GSFC/SDO) #

When a rather large-sized (M 3.6 class) flare occurred near the edge of the Sun, it blew out a gorgeous, waving mass of erupting plasma that swirled and twisted over a 90-minute period on February 24, 2011. This event was captured in extreme ultraviolet light by NASA's Solar Dynamics Observatory spacecraft . Some of the material blew out into space and other portions fell back to the surface. #

A closeup of the solar surface. Part of the largest sunspot in Active Region 10030 recorded on July 15, 2002, with the Swedish 1-m Solar Telescope on La Palma. The width of the cells near the top of the image are roughly 1,000 km. The central part of the sunspot ("the umbra") looks dark because the strong magnetic fields there stop upwelling hot gas from the solar interior. The thread-like structures surrounding the umbra make up the penumbra. Dark cores are clearly visible in some of the bright penumbral filaments that stick out into the umbra. (Royal Swedish Academy of Sciences) # #

NASA's SOHO satellite watched as a fairly bright comet dove towards the Sun in a white streak and was not seen again after its close encounter on May 10-11, 2011. In this coronagraph the Sun (represented by a white circle) is blocked by the red occulting disk so that the faint structures in the Sun's corona can be discerned. Interestingly, a coronal mass ejection blasted out to the right just as the comet is approaching the Sun. Scientists, however, have yet to find a convincing physical connection between sun-grazing comets and coronal mass ejections. In fact, analysis of this CME using images from the Solar Dynamics Observatory shows that the CME erupted before the comet came close enough to the solar surface to interact with strong magnetic fields. #

On October 6, 2008, NASA's MESSENGER spacecraft successfully completed its second flyby of Mercury. The next day, the images taken during the flyby encounter began to be received back on Earth. The spectacular image shown here is one of the first to be returned and shows a WAC image of the departing planet taken about 90 minutes after the spacecraft's closest approach to Mercury. The bright crater just south of the center of the image is Kuiper, identified on images from the Mariner 10 mission in the 1970s. (NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington) # #

A mosaic from NASA's MESSENGER spacecraft of Mercury's Spitteler and Holberg craters, seen on March, 30, 2011 (NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington) # #

MESSENGER views Mercury's south pole and terminator from an altitude of 10,240 km (6363 miles). The surface temperature in the upper part of this image, bathed in light from the nearby Sun, is about 700 Kelvin (430 °C, 800 °F). In the lower, unlit portion, temperatures can quickly drop drastically to 110 Kelvin (-163 °C, -261 °F) some parts of the poles never receive sunlight and remain at 90 Kelvin (-183 °C. -297 °F). (NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington) # #

A view of The second planet from the Sun, Venus, as seen on June 5, 2007 as NASA's MESSENGER spacecraft flew past. Thick clouds of sulfuric acid obscures the planet's surface completely, reflecting some sunlight back into space, while trapping heat below in a 460 °C (860 °F) greenhouse. (NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington) # #

Above the Earth's moon now, NASA's Lunar Reconnaissance Orbiter(LRO) captured this oblique view of Aitken crater, including the central peak and northern walls. The Scene is about 30 km wide (NASA/GSFC/Arizona State University) # #

A patchwork of material makes up the fresh ejecta blanket of an unnamed 1 km diameter crater on the Moon, seen by NASA's Lunar Reconnaissance Orbiter, on April 21, 2011. (NASA/GSFC/Arizona State University)# #

A recent view of the Apollo 14 landing site -- acquired January 25, 2011 by NASA's Lunar Reconnaissance Orbiter. Tracks made 40 years ago by NASA astronauts on February 5 and 6, 1971, are still visible, undisturbed. The descent stage of lunar module Antares in center, image width is 1,500 meters (NASA/GSFC/Arizona State University) # #

This detailed, photo-like view of Earth is based largely on observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite. This image focuses on the massive Pacific Ocean, part of the important water ecosystem that covers 75% of our home planet. This image was featured as part of a story on water at NASA's Earth Observatory. (NASA/Robert Simmon and Marit Jentoft-Nilsen, based on MODIS data)# #

The Earth's moon, distorted heavily by layers of atmosphere, sets above the Indian Ocean, as seen by astronauts aboard the International Space Station on April 17, 2011. (NASA)# #

A panoramic view across central South America at sunset, looking towards the northeast, as seen by an astronaut aboard the ISS on April 12, 2011. (NASA) # #

On October 28, 2010, astronauts aboard the ISS gazed down on the Earth at night and captured this scene, with Brussels, Paris, and Milan brightly lit. (NASA)# #

Snowfall across 30 U.S. States last February shows snow from the Great Plains to New England under the cold and clear skies that followed. The storms made for a nice snowy satellite-view panorama in this February 3, 2011 GOES-13 satellite image captured at (11:45 a.m. EST). (NOAA/NASA GOES Project)# #

The first quarter Moon and the Aurora Australis appear above the Earth, as seen by astronauts aboard the ISS on September 14, 2010. (NASA)# #

South Georgia is an arc-shaped island that lies some 2,000 kilometers (1,200 miles) east of the southern tip of South America. Along South Georgia's east coast, Neumayer Glacier snakes toward the ocean. The Advanced Land Imager (ALI) on NASA's Earth Observing-1 (EO-1) satellite captured this natural-color image of the glacier on January 4, 2009. (NASA EO-1 team)# #

NASA space physicist James Spann took this picture at Poker Flats, Alaska, where he was attending a scientific conference to study auroras on March 1, 2011. (NASA/GSFC/James Spann)# #

An astronaut's view of a sunrise, viewed through the cupola window of the ISS on November 26th, 2010. (NASA)# #

On to Mars next - this image shows a remarkable double crater with a shared rim and North-South trending ejecta deposits. These two craters must have formed simultaneously. Image acquired in February, 2011 by NASA's High Resolution Imaging Science Experiment (HiRISE), a camera on board the Mars Reconnaissance Orbiter (MRO). (NASA/JPL/University of Arizona)# #

A land formation covered by drifting sand on Mars' surface, in a crater in Sinus Sabaeus Region. Image acquired on April 1, 2011 by NASA's HiRISE camera. (NASA/JPL/University of Arizona)# #

HiRISE peers down on Mars Rover Opportunity as it sits perched on the edge of Santa Maria crater (visible as dark dot at top left of crater). Opportunity's tracks can be seen faintly across the center, leading to the right. This image was taken on March 1, 2011, after Opportunity had spent several days studying the area. (NASA/JPL/University of Arizona) # #

Mars Rover Opportunity looks across the surface of the planet, a small crater nearby, in this mosaic of images acquired in May of 2011. (NASA/JPL)# #

An area of Mars' Holden Crater, one of four candidate landing sites for Curiosity, acquired on January 4, 2011. NASA is still deciding on the final landing area for the next rover, the Mars Science Laboratory, named Curiosity, scheduled to launch on November 25, 2011 and land on Mars on August 6, 2012. (NASA/JPL/University of Arizona)# #

This March 31, 2011 image of Mars rover Spirit shows it in it's final resting spot. Sunlight glints off its surface, as it sits stuck in loose sand, trapped for two years now. Over a year ago, its radio stopped functioning, and just last Wednesday, may 25th, NASA engineers sent their final signal to Spirit, hoping for a response, and receiving none. (NASA/JPL/University of Arizona) # #

A close-up view of comet Hartley 2, taken as NASA's EPOXI mission approached the comet on November 4, 2010. (NASA/JPL-Caltech/UMD)# #

This image shows the first, unprocessed image obtained by NASA's Dawn spacecraft of it's target, the giant asteroid Vesta. It was obtained by Dawn's framing camera on May 3, 2011, from a distance of about 1.2 million kilometers (750,000 miles). Vesta is inside the white glow at the center of the image. The giant asteroid reflects so much sunlight that its size is dramatically exaggerated at this exposure. Vesta is 330 miles (530 kilometers) in diameter and the second most massive object in the asteroid belt. But, in Dawn's early approach images, Vesta only appears approximately five pixels across in size. This and other images help Dawn fine tune navigation during its approach to Vesta, with arrival expected on July 16, 2011. (NASA/JPL)# #

An image of Jupiter, seen by NASA's Hubble telescope on July 23, 2009, after a comet or asteroid recenetly plunged into Jupiter's atmosphere and disintegrated.(NASA, ESA, Space Telescope Science Institute, Jupiter Impact Team)# #

Outward to Saturn now, this image taken by NASA's Cassini Orbiter on April 25, 2011, shows several of Saturn's moons aligned along its rings, with Saturn's dark side taking up the left third of the image. (NASA/JPL/Space Science Institute) # #

A close view of Saturn's small moon Helene during a Cassini flyby on March 3, 2010. Saturn's atmosphere makes up the background of this composition. This view looks toward the anti-Saturn side of Helene (33 kilometers, 21 miles across). (NASA/JPL/Space Science Institute) # #

Small water ice particles fly from fissures in the south polar region of Saturn's moon Enceladus in this image taken during the August 13, 2010, flyby of the moon by NASA's Cassini spacecraft. (NASA/JPL/Space Science Institute)# #

Vertical structures, among the tallest seen in Saturn's main rings, rise abruptly from the edge of Saturn's B ring to cast long shadows on the ring in this image taken by NASA's Cassini spacecraft two weeks before the planet's August 2009 equinox. (NASA/JPL/Space Science Institute)# #

Cassini looks toward the dark side of Saturn's largest moon and captures the halo-like ring produced by sunlight scattering through the periphery of Titan's atmosphere. (NASA/JPL/Space Science Institute)# #

Saturn's icy moon Enceladus appears in this Cassini image, Saturn and its rings in the background. (NASA/JPL/Space Science Institute)# #

Saturn's moons Titan and Enceladus pass high above the rings and surface of the planet below, in this image taken by Cassini on May 21, 2011. (NASA/JPL/Space Science Institute)# #

The shadows of Saturn's rings cast onto the massive planet appear as a thin band at the equator in this image taken as the planet approached its August 2009 equinox. (NASA/JPL/Space Science Institute)# #