The intricate structure of the Helix Nebula, seen in January, is featured as one of National Geographic News editor's picks for the best space pictures of 2012. (See more nebula pictures.)
The rust-colored remains of a star like our sun, the Helix puffed up as it died and shed its shells of gas and dust into space.
In visible light, fine details in the Helix are largely obscured by dust. But the infrared view—snapped by the European Southern Observatory's VISTA telescope—can pierce this veil to see radiating filaments of cooler gas in the rings as well as a faint halo of thinly spread gas that extends to at least four light-years from the dead star's core.
"This deep-space picture has an unusual sense of scale: The individual bright spots placed throughout the image give it a 3-D feeling of depth, while the fine detail hints at the huge size of this planetary nebula."—Chris Combs, news photo editor
A long-exposure picture—posted to the night-sky photography community The World at Night (TWAN) in November—captures the stars' nightly swirl while auroras set the horizon aglow over Australia's Mornington Peninsula.
Auroras are born when the sun sends charged particles, known as solar wind, speeding toward Earth's atmosphere, where they slam into oxygen and nitrogen atoms in the ionosphere above the planet's magnetic North and South Poles. The energy released by these collisions creates glowing colors some 60 to 620 miles (97 to 1,000 kilometers) aloft.
"This is a beautifully simple star-trail photograph. I like the vivid colors on the horizon and the understated foreground. Although it's a good rule of thumb to incorporate a prominent foreground into a night-sky picture like this, sometimes it's best to let the stars do the talking!"—Chris Combs, news photo editor
Southern Sky Show
From their vantage point high above Earth in March, astronauts on the International Space Station were able to capture daybreak (left) and nighttime auroras in a single frame.
Snapped over the Indian Ocean, the picture also shows a Russian Soyuz spacecraft (center) and a Progress resupply ship docked at the station.
"I like the way that this photograph gives a sense of what it must be like to look out the window of a space station every day. It doesn't shy away from the hardware. The little lick of aurora on the right doesn't hurt either!"—Chris Combs, news photo editor
This image of a supernova remnant called the Witch's Broom received high commendation in the Deep Space category in the 2012 Astronomy Photographer of the Year competition, whose results were announced in September.
Taken by American Robert Franke, the picture shows scattering debris from a Milky Way star that exploded several thousand years ago. These cosmic filaments are part of the Veil Nebula, one of the largest supernova remnants in the sky. It lies some 1,400 light-years away in the constellation Cygnus.
"It's hard to find deep-space images that give you a sense of shape or structure. Perhaps this is why the 'Pillars of Creation' image was so successful."—Chris Combs, news photo editor
Earth's most famous light formation hangs over a landscape saturated by the glow of a full moon in Longyearbyen, Norway, in June.
The photographer, who recently submitted this image to National Geographic's Your Shot, said it was the most beautiful northern lights display he had ever witnessed. Referred to as the aurora borealis around the Arctic Circle, the light show also appears in southern polar latitudes, where it's known as the aurora australis.
"We have the good fortune of being able to run many beautiful aurora photographs each year. I like the delicate color of the moonlit mountains in this one and the simplicity of the aurora itself."—Chris Combs, news photo editor
Photograph by Max Edin, Your Shot
It might look as if someone sculpted a pigeon in the Martian sand. But this image from NASA's Mars Reconnaissance Orbiter, released in April, shows naturally shaped dunes in the red planet's north polar region, which are lined and speckled by defrosting winter ice.
White regions indicate where fine-grained frost still rims the polar dunes. Dark blotches, meanwhile, are most likely made from sediment kicked up by carbon dioxide "geysers" created as ice layers sublimate, or turn directly from a solid to a gas.
"The grittiness of this image reminded me of dirty, melting snow here on Earth. I try to find space images that bring it home, showing us something familiar that we can relate to."—Chris Combs, news photo editor
Although the sun is only minimally covered in this picture, the so-called annular eclipse went on to create a "ring of fire" for sky-watchers in parts of Asia and the U.S. West. (See more annular solar eclipse pictures.)
An annular eclipse happens when the moon lines up between Earth and the sun and when the dark moon's apparent diameter is smaller than the visible disk of the sun, leaving a ring—or annulus—of fiery light around the edges.
"While an astronomer might have been disappointed by these clouds, I felt that they gave this photograph an interesting, brooding feeling. It evokes the same sense of mystery that Earthlings must have felt for thousands of years as the sun grew slowly dark during an eclipse. A more synthetic or 'clean' image of an eclipse doesn't feel as powerful to me as a view like this."—Chris Combs, news photo editor
Astronaut Edwin "Buzz" Aldrin snaps a self-portrait while spacewalking during NASA's Gemini 12 mission in November 1966. Part of a camera (foreground) and the antenna of an unmanned Agena target vehicle—used during the Gemini program for rendezvous and docking practice—are visible in the left corner of the frame.
"Many pictures of suited astronauts don't show their faces. I like the sense of humanity in this picture, even though most of his face is in shadow."—Chris Combs, news photo editor
Before he joins the Avengers, Thor may need to retrieve his helmet—which is floating in space 15,000 light-years away.
Also known as NGC 2359, Thor's Helmet is a nebula found in the constellation Canis Major. As seen in this picture from May—taken by the Cerro Tololo Inter-American Observatory in Chile—the cosmic cloud of dust and gas is being shaped like a winged helm by outpourings of radiation from the massive stars inside.
"This is a beautiful picture, with a rewarding complexity; as you keep looking, more and more detail turns up. Astro-imagers, take note of the careful colorization that went into this multispectrum image."—Chris Combs, news photo editor
"The deep shadows and high contrast of this elegant picture remind me of a silver gelatin black-and-white photograph. I cropped a tiny moon off of the very top of this image to keep it simple, and because it wasn't very easy to see once the picture was sized down."—Chris Combs, news photo editor
A type of solar explosion called a coronal mass ejection sent solar radiation out from the sun at 900 miles per second, as seen in an image released by NASA on September 17.
The sudden burst of radiation didn't collide with Earth, but it did hit our planet's magnetic field, producing illuminated auroras in the sky in some parts of the world.
"I keep a close eye on NASA's solarmissions and the site SpaceWeather.com because they give me a few days' advance warning for aurora borealis. They publish many images of the sun that are most useful to a trained eye, but this one is very clear and easy to understand—and awe-inspiring."—Chris Combs, news photo editor
A phytoplankton bloom traces a figure eight in the South Atlantic Ocean, about 373 miles (600 kilometers) east of the British-held Falkland Islands in a European Space Agency satellite picture from January.
Phytoplankton are microscopic organisms that make up the base of the marine food chain. In spring and summer, upwelling nutrients from deeper waters can fuel massive plankton blooms at the surface.
Different types and quantities of phytoplankton appear as differently colored blooms, as seen in the varying shades of blue and green above.
"A photojournalism teacher once pointed out to me that the best photos of an event can come before it's supposed to start or well after it's ended. This is a perfect example!"—Chris Combs, news photo editor
Three stars—including the red dwarf Gliese 667 C (far left)—set over the "super Earth" Gliese 667 Cc in an artist's conception.
Such rocky worlds abound around red dwarfs (stars smaller and cooler than our sun), according to March results from the HARPS (High Accuracy Radial velocity Planet Searcher) telescope at the European Southern Observatory. Radial velocity is a planet-hunting technique that looks for wobbles in a star's light, which can indicate the gravitational tugs of orbiting worlds.
"This illustration does a nice job of showing both the similarities and the differences between this exoplanet and Earth."—Chris Combs, news photo editor
Ready for its closeup but all alone on Mars, NASA's rover Curiosity created this self-portrait on Halloween. The image was stitched together from 55 high-resolution shots snapped by the Mars Hand Lens Imager (MAHLI) perched on the end of Curiosity's robotic arm.
The pictures were taken at "Rocknest," the location in Gale Crater where the mission first scoop-sampled Martian soil. Four scoop scars remain visible in the soil in front the rover, while the base of three-mile-high (five-kilometer-high) Mount Sharp rises to the right of Curiosity.
"I could quibble with the decision to omit the robotic arm from this multiple-exposure composite photograph, but this image does a good job of putting us right there on Mars!"—Chris Combs, news photo editor
The ancient fan looks similar to modern deltas on Earth, which form when water in a channel flows into a larger body of water, as with the Nile Delta in Egypt. As the water spreads out, it moves slower and drops any sediment it's carrying, creating the fanlike structure.
"I could look at the rich detail of this image all day."—Chris Combs, news photo editor
A February picture from the European Southern Observatory's Very Large Telescope is the most detailed infrared view yet of the Carina Nebula. This bustling stellar nursery sits about 7,500 light-years from Earth and is home to several of the brightest and most massive stars known.
Radiation from the hot, young stars inside causes the large nebula to glow brightly in visible light. But the new infrared view can also pierce the space cloud's veil of dust to see hundreds of thousands of fainter stars that were previously invisible.
"I once watched an artist in Times Square use canned spray paint and a deft hand to make the most fantastic planets and nebulae in a night sky. This image of a real nebula is even more dramatic than his painting!"—Chris Combs, news photo editor
The last of five shuttles in the U.S. space shuttle program,Endeavour was formally retired in September and made its final aerial journey, bound for the California Science Museum (CSC) in downtown Los Angeles.
Endeavour was the youngest of the shuttle fleet, having been built after the 1986 explosion of the Challenger shuttle during liftoff.
"What a view! There were many photographs of the space shuttles being retired, but few were as eye-catching as this."—Chris Combs, news photo editor
This image of the Milky Way's vast star fields hanging over a valley of human-made light was recognized in the 2012 Astronomy Photographer of the Year competition run by the U.K.’s Royal Observatory Greenwich.
To get the shot, photographer Tunç Tezel trekked to Uludag National Park near his hometown of Bursa, Turkey. He intended to watch the moon and evening planets, then take in the Perseids meteor shower.
"We live in a spiral arm of the Milky Way, so when we gaze through the thickness of our galaxy, we see it as a band of dense star fields encircling the sky," said Marek Kukula, the Royal Observatory's public astronomer and a contest judge.
"I like the way this view of the Milky Way also shows us a compelling foreground landscape. It also hints at the astronomy problems caused by light pollution."—Chris Combs, news photo editor
A vortex of storm clouds swirls around Saturn's north pole in this November 27 image taken from about 250,000 miles (about 400,000 kilometers) away by NASA's Cassini spacecraft.
Cassini's cameras have revealed a cyclone-like pattern at the pole before but only in infrared wavelengths because the north pole was in darkness during the planet's long winter. As Saturn slowly orbits the sun, light has finally begun to reach the north pole.