The far side of the moon, illuminated by the sun as it crosses between the DSCOVR spacecraft’s Earth Polychromatic Imaging Camera (EPIC) camera and telescope, and the Earth, one million miles away, in a NASA image taken on July 16, 2015. The lunar far side lacks the large, dark, basaltic plains, or maria, that are so prominent on the Earth-facing side, NASA said in a news release. #

The Sun blew out a coronal mass ejection along with part of a solar filament over a three-hour period on February 24, 2015. While some of the strands fell back into the Sun, a substantial part raced into space in a bright cloud of particles, as observed by the SOHO spacecraft. #

Day 179 of astronaut Scott Kelly’s year in space aboard the International Space Station (ISS). Kelly: “The Nile at night is a beautiful sight for these sore eyes. Good night from @space_station!” #

New York City, imaged by the crew of Expedition 43 aboard the International Space Station on May 23, 2015. NASA astronaut Scott Kelly tweeted this image out with the following comment: “Good morning #Manhattan! #bigapple #YearInSpace.” #

Astronaut Scott Kelly posted this photo to Twitter on August 9, 2015, with the caption, “Day 135. #MilkyWay. You’re old, dusty, gassy and warped. But beautiful. Good night from @space_station!” #

Astronaut Scott Kelly posted this picture of the Bahamas taken from the ISS on Twitter on July 19, 2015, with the caption, “#Bahamas, the strokes of your watercolors are always a refreshing sight. #YearInSpace.” #

The International Space Station, with a crew of six on board, is seen in silhouette (center) as it transits the moon at roughly five miles per second, on August 2, 2015, from Woodford, Virginia. #

Astronaut Scott Kelly posted this photo taken from the International Space Station to Twitter on August 10, 2015 with the caption, “#GoodMorning to those in the western #USA. Looks like there’s a lot going on down there. #YearInSpace.” #

A double eclipse. The moon (left) and the Earth (top) transit the sun together, as seen from the Solar Dynamics Observatory on September 13, 2015. The edge of Earth appears fuzzy because the atmosphere blocks different amounts of light at different altitudes. #

This single-frame Rosetta navigation camera image of Comet 67P/Churyumov-Gerasimenko was taken on October 19, 2014, from a distance of 9.9 kilometers from the comet’s center, or approximately 7.9 kilometers from the surface. This image looks across the neck from the comet’s small lobe in the foreground to the large lobe in the background. #

A dark line is seen snaking across the lower half of the sun in this image from NASA’s Solar Dynamics Observatory (SDO) taken on February 10, 2015. SDO shows colder material as dark and hotter material as light, so the line is, in fact, an enormous swatch of colder material hovering in the sun's atmosphere, the corona. Stretched out, that line, or solar filament, would be more than 533,000 miles long, or longer than 67 Earths lined up in a row, according to NASA. #

This image, taken by NASA’s Dawn spacecraft, shows the Occator crater on the dwarf planet Ceres, home to a collection of intriguing bright spots. The bright spots are much brighter than the rest of Ceres’s surface, and tend to appear overexposed in most images. This view is a composite of two images of Occator: one using a short exposure that captures the detail in the bright spots, and one where the background surface is captured at normal exposure. The images were obtained by Dawn during the mission’s High Altitude Mapping Orbit (HAMO) phase, from which the spacecraft imaged the surface at a resolution of about 450 feet (140 meters) per pixel. #

Dunes and ripples in Nili Patera, a region on Mars in which dunes and ripples are moving rapidly. NASA’s HiRISE instrument continues to monitor this area from orbit every couple of months to see changes over seasonal and annual time scales. #

NASA’s Curiosity Mars rover is seen at the site from which it reached down to drill into a rock target called “Buckskin” on lower Mount Sharp in this low-angle self-portrait taken on August 5, 2015. The selfie combines several component images taken by Curiosity’s Mars Hand Lens Imager (MAHLI) during the 1,065th Martian day, or sol, of the rover's work on Mars. #

A southward-looking panorama combining images from both cameras of the Mast Camera (Mastcam) instrument on NASA’s Curiosity Mars Rover shows diverse geological textures on Mount Sharp. Three years after landing on Mars, the mission is investigating this layered mountain for evidence about changes in Martian environmental conditions, from an ancient time when conditions were favorable for microbial life to the much-drier present. Gravel and sand ripples fill the foreground, typical of terrains that Curiosity traversed to reach Mount Sharp from its landing site. Outcrops in the midfield are of two types: dust-covered, smooth bedrock that forms the base of the mountain, and sandstone ridges that shed boulders as they erode. Rounded buttes in the distance contain sulfate minerals, perhaps indicating a change in the availability of water when they formed. The component images were taken on April 10 and 11, 2015, the 952nd and 953rd Martian days (or sols) since the rover's landing on Mars on August 6, 2012. #

A possible landing site for the 2020 Mars mission: Jezero Crater. Jezero Crater is an ancient crater where clay minerals have been detected, and with a delta deposit indicating that water was once flowing into a lake. Since clays form the in presence of water, this crater would be a very good candidate for a lander to explore and build on what we’ve learned from the Mars Science Laboratory. #

NASA’s Curiosity Mars rover recorded this view of the sun setting at the close of the mission’s 956th Martian day, or sol (April 15, 2015), from the rover’s location in Gale Crater. This was the first sunset observed in color by Curiosity. Dust in the Martian atmosphere has fine particles that permit blue light to penetrate the atmosphere more efficiently than longer-wavelength colors. That causes the blue colors in the mixed light coming from the sun to stay closer to the sun’s part of the sky, compared to the wider scattering of yellow and red colors. The effect is most pronounced near sunset, when light from the sun passes through a longer path in the atmosphere than it does at midday. #

As Europe enjoyed a partial solar eclipse on the morning of March 20, 2015, ESA’s Sun-watching Proba-2 minisatellite had a ringside seat from orbit. Proba-2 used its SWAP imager to capture the Moon passing in front of the Sun in a near totality. #

The tops of Saturn’s uppermost cloud layers, with part of its rings in the background. Astronomers study Saturn's cloud dynamics in part to test and improve our understanding of fluid flows. This view looks toward the sunlit side of the rings from about 25 degrees above the ringplane on August 23, 2014. #

This view from NASA's Cassini spacecraft looks toward Saturn's icy moon Dione, with giant Saturn and its rings in the background, just prior to the mission's final close approach to the moon on August 17, 2015. #

Triple crescents. The three moons shown here—Titan (3,200 miles or 5,150 kilometers across), Mimas (246 miles or 396 kilometers across), and Rhea (949 miles or 1,527 kilometers across)—show marked contrasts on March 25, 2015. Titan, the largest moon in this image, appears fuzzy because we only see its cloud layers. And because Titan’s atmosphere refracts light around the moon, its crescent “wraps” just a little further around the moon than it would on an airless body. Rhea (upper left) appears rough because its icy surface is heavily cratered. And a close inspection of Mimas (center bottom), though difficult to see at this scale, shows surface irregularities due to its own violent history. The view was obtained at a distance of approximately 2.7 million miles (4.3 million kilometers) from Titan. Mimas was 1.9 million miles (3.0 million kilometers) away, and Rhea was 1.6 million miles (2.6 million kilometers) away. #

In this image, we're seeing Saturn's A ring in the lower part of the image and the limb of Saturn in the upper, on December 5, 2014. In addition, the rings cast their shadows onto the portion of the planet imaged here, creating alternating patterns of light and dark. This pattern is visible even through the A ring, which, unlike the core of the nearby B ring, is not completely opaque. #

NASA’s Cassini imaging scientists processed this view of Saturn’s moon Dione, taken during a close flyby on June 16, 2015. This was Cassini’s fourth targeted flyby of Dione and had a close approach altitude of 321 miles (516 kilometers) from Dione's surface. The bright rings of Saturn can be seen at left, in the background of the image. #

This July 14, 2015, photo, provided by NASA, shows a synthetic perspective view of Pluto, based on high-resolution images downlinked from NASA’s New Horizons spacecraft. #

This image of Pluto’s largest moon, Charon—taken by NASA’s New Horizons spacecraft 10 hours before its closest approach to Pluto on July 14, 2015, from a distance of 290,000 miles (470,000 kilometers)—is a higher-quality version of a Charon image released on July 15. Charon, which is 750 miles (1,200 kilometers) in diameter, displays a surprisingly complex geological history, including tectonic fracturing; relatively smooth, fractured plains in the lower right; several enigmatic mountains surrounded by sunken terrain features on the right side; and heavily cratered regions in the center and upper left portion of the disk. There are also complex reflectivity patterns on Charon's surface, including bright and dark crater rays, and the conspicuous dark north polar region at the top of the image. #

Just 15 minutes after its closest approach to Pluto on July 14, 2015, NASA’s New Horizons spacecraft looked back toward the sun and captured this near-sunset view of the rugged, icy mountains and flat ice plains extending to Pluto’s horizon. The smooth expanse of the informally named icy plain Sputnik Planum (right) is flanked to the west (left) by rugged mountains up to 11,000 feet (3,500 meters) high, including the informally named Norgay Montes in the foreground and Hillary Montes on the skyline. To the right, east of Sputnik, rougher terrain is cut by apparent glaciers. The backlighting highlights more than a dozen layers of haze in Pluto’s tenuous but distended atmosphere. The image was taken from a distance of 11,000 miles (18,000 kilometers) to Pluto; the scene is 780 miles (1,250 kilometers) wide. #