The empty payload bay of the space shuttle Endeavour is illuminated as the spacecraft zooms over city lights on Earth in May. This shot of the shuttle, at the time docked with the International Space Station, is among National Geographic News editor's picks for the best space pictures of 2011.
Editor's Note: A picture of the Milky Way over the Himalaya was removed from this gallery December 19 because photo editors and astronomers determined that the image was unacceptably manipulated.
Photograph courtesy NASA
Looking like a multihued jellyfish, the Betsiboka River in northwestern Madagascar flows into Bombetoka Bay, which in turn empties into the Mozambique Channel, as seen in a satellite picture released by the European Space Agency in August.
Sandbars and islands between the "tentacles" appear rust colored due to deposits of sediments that had washed into the streams and rivers during heavy rains.
"If we considered dark, starry skies a part of nature and our living world heritage, then we would try to preserve it like the other parts of nature," TWAN founder and contest judge Babak Tafreshi said in an email to National Geographic News.
The puffy cloud of debris is all that's left of a massive star that exploded some 13,000 light-years away. Light from the powerful blast reached Earth in 1572, making the object briefly visible to the naked eye, even during the day.
The new composite picture shows low-energy x-rays in red and high-energy x-rays in blue. It also reveals, for the first time, bright x-ray stripes—seen in white along the right edge of the remnant—supporting theories that supernovae are sources of high-speed particles known as cosmic rays.
A galaxy slightly smaller than our own Milky Way is getting its arm twisted, and a cosmic bully may be to blame.
As seen in a picture released in August by scientists with the NASA/ESA Hubble Space Telescope, one of galaxy NGC 2146's arms is bent at a 45-degree angle, such that the dense limb has looped in front of the galaxy's core, as seen from Earth.
The most likely explanation is that the gravity of an unidentified nearby galaxy is disturbing NGC 2146's arm, causing the galaxy to warp.
The annual Orionid meteor shower peaked in activity in the early morning hours of October 22, as tiny remnants shed from Halley's comet plummeted through Earth's atmosphere. From dark locations, up to two dozen shooting stars an hour were visible during the peak.
Jeffrey Berkes of West Chester, Pennsylvania, managed to frame an Orionid streaking above a country lake, keeping the glare from a waning crescent moon in check behind autumn foliage.
"The moon beginning its ascent around 2:15 a.m. worried me a little bit, but the Orionids were streaking bright, and I counted a couple dozen during the night," Berkes wrote in his caption for the image, which he submitted to National Geographic's My Shot website.
Seen in visible light, the star known as Zeta Ophiuchi is dim, red, and surrounded by inky blackness. But in infrared, the star becomes a bright blue ball of fire topped with a glowing "mustache" of interstellar dust, as seen in a picture, released in January, from NASA's Wide-field Infrared Survey Explorer, or WISE, telescope.
Astronomers think Zeta Ophiuchi was once part of a stellar duo known as a binary pair. Then Zeta Ophiuchi's companion star exploded, releasing Zeta Ophiuchi to go flying away on a fast-tracked solo act through space.
The star is now plowing through a cloud of dust and gas at 15 miles (24 kilometers) a second. As Zeta Ophiuchi moves, its powerful radiation is compressing the gas and dust in its path, creating a bow shock that shines in infrared.
Later, in November, Fossum, Russian cosmonaut Sergei Volkov, and Japanese astronaut Satoshi Furukawa returned to Earth after more than five months aboard the space station. The landing marked the first time astronauts had returned to Earth from the space station since NASA retired its space shuttle fleet in July.
The totally eclipsed moon shines amid the dense stars of our Milky Way galaxy in a stitched panorama picture taken in June from the Alborz Mountains of Iran. The eclipsed moon glows orange-red due to indirect light from the sun, which becomes reddish as it passes through Earth's atmosphere.
The internationally funded ALMA project is being hailed as the most complex ground-based observatory yet built. When construction is complete in 2013, the array will feature 66 antennas spread across 9.9 miles (16 kilometers). The antennas will be linked with fiber optics to function as a single telescope.
"We've been waiting a very long time to get to the point where ALMA is really able to do science. Some people have been working on this project for more than 20 years," project scientist Richard Hills told the AFP news service. "So it has been a long road, but all the bits and pieces that we need to make this telescope work now [are coming] together."
A September picture of the sun setting over Curitiba, Brazil, shows the dark blotch of sunspot AR1302, an active region that stretched about 93,000 miles (150,000 kilometers) from end to end and was visible to the naked eye.
"It was overcast and cold all day long, but at the end of the day a break in the clouds revealed the sun and AR1302," photographer Fabiano Belisário Diniz told SpaceWeather.com. "What a great sight!"
Photograph courtesy Fabiano Belisario Diniz
In September scientists announced that high-resolution photographs from NASA's MESSENGER spacecraft had revealed shallow, rimless, irregularly shaped depressions—similar to the holes in Swiss cheese—in impact craters all over the planet Mercury. The odd holes are unlike any other landform yet seen in the solar system.
Dubbed hollows, the depressions are often seen in clusters on the walls, floors, and peaks of craters. Many hollows have smooth, flat bottoms and feature highly reflective material.
While Mercury had previously been thought of as a geologically dead planet, with few changes to its surface over the past billion years, "these [hollows] just look fresh," said study co-author David Blewett, of the Johns Hopkins University Applied Physics Laboratory in Maryland. "I think there's a distinct possibility that they're active today."
Image courtesy NASA/Johns Hopkins APL/Carnegie Institution of Washington
Man in the Mirrors
The face of project scientist Mark Clampin is reflected in the flight mirrors of the James Webb Space Telescope at NASA's Marshall Space Flight Center in Alabama in a picture released in May.
The telescope's main mirror will ultimately be made of 18 hexagonal segments, fitted together to create a 21-foot-wide (6.5-meter-wide) honeycomb. Billed as the successor to the Hubble Space Telescope, the James Webb is due to launch in 2018.