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Explanation: Moonlight illuminates a snowy scene in this night land and skyscape made on January 17 from Lower Miller Creek, Alaska, USA. Overexposed near the mountainous western horizon is the first quarter Moon itself, surrounded by an icy halo and flanked left and right by moondogs. Sometimes called mock moons, a more scientific name for the luminous apparations is paraselenae (plural). Analogous to a sundog or parhelion, a paraselene is produced by moonlight refracted through thin, hexagonal, plate-shaped ice crystals in high cirrus clouds. As determined by the crystal geometry, paraselenae are seen at an angle of 22 degrees or...

Explanation: On January 25 (UT) 2004, the Opportunity rover fell to Mars, making today the 9th anniversary of its landing. After more than 3,200 sols (Mars solar days) the golf cart-sized robot from Earth is still actively exploring the Red Planet, though its original mission plan was for three months. Having driven some 35 kilometers (22 miles) from its landing site, Opportunity's panoramic camera recorded the segments of this scene, in November and December of last year. The digitally stitched panorama spans more than 210 degrees across the Matijevic Hill area along the western rim of Endeavour Crater. Features dubbed...

Explanation: Clouds on a summer night frame this sea and skyscape, recorded earlier this month near Buenos Aires, Argentina. But planet Earth's clouds are not the only clouds on the scene. Starry clouds and nebulae along the southern hemisphere's summer Milky Way arc above the horizon, including the dark Coal Sack near the Southern Cross and the tantalizing pinkish glow of the Carina Nebula. Both the Large (top center) and Small Magellanic Clouds are also in view, small galaxies in their own right and satellites of the Milky Way up to 200,000 light-years distant. Alpha star of the Carina constellation...

Explanation: Large spiral galaxy NGC 4945 is seen edge-on near the center of this cosmic galaxy portrait. In fact, NGC 4945 is almost the size of our own Milky Way Galaxy. Its own dusty disk, young blue star clusters, and pink star forming regions standout in the sharp, colorful telescopic image. About 13 million light-years distant toward the expansive southern constellation Centaurus, NGC 4945 is only about six times farther away than Andromeda, the nearest large spiral galaxy to the Milky Way. Though the galaxy's central region is largely hidden from view for optical telescopes, X-ray and infrared observations indicate...

Explanation: The North America nebula on the sky can do what the North America continent on Earth cannot -- form stars. Specifically, in analogy to the Earth-confined continent, the bright part that appears as Central America and Mexico is actually a hot bed of gas, dust, and newly formed stars known as the Cygnus Wall. The above image shows the star forming wall lit and eroded by bright young stars, and partly hidden by the dark dust they have created. The part of the North America nebula (NGC 7000) shown spans about 15 light years and lies about 1,500 light...

Explanation: What would it look like to land on Saturn's moon Titan? The European Space Agency's Huygens probe set down on the Solar System's cloudiest moon in 2005, and a time-lapse video of its descent images was created. Huygens separated from the robotic Cassini spacecraft soon after it achieved orbit around Saturn in late 2004 and began approaching Titan. For two hours after arriving, Huygens plummeted toward Titan's surface, recording at first only the shrouded moon's opaque atmosphere. The computerized truck-tire sized probe soon deployed a parachute to slow its decent, pierced the thick clouds, and began transmitting images of...

Explanation: What is it? It was found at the bottom of the sea aboard an ancient Greek ship. Its seeming complexity has prompted decades of study, although some of its functions remained unknown. X-ray images of the device have confirmed the nature of the Antikythera mechanism, and discovered several surprising functions. The Antikythera mechanism has been discovered to be a mechanical computer of an accuracy thought impossible in 80 BC, when the ship that carried it sank. Such sophisticated technology was not thought to be developed by humanity for another 1,000 years. Its wheels and gears create a portable orrery...

Scientists have long believed that comets and, or a type of very primitive meteorite called carbonaceous chondrites were the sources of early Earth's volatile elements -- which include hydrogen, nitrogen, and carbon -- and possibly organic material, too. Understanding where these volatiles came from is crucial for determining the origins of both water and life on the planet. New research led by Carnegie's Conel Alexander focuses on frozen water that was distributed throughout much of the early Solar System, but probably not in the materials that aggregated to initially form Earth... It has been suggested that both comets and carbonaceous...

The White River Ash blasted from giant eruptions somewhere in today's Wrangell-St. Elias Mountains, drifted as far away as Ireland and Germany... Ash from the White River eruptions, possibly from 15,638-foot Mount Churchill or at least close to it, left an easy-to-see mark on eastern Alaska and northwestern Canada. Explorer Frederick Schwatka documented the ash in 1885 in his book "Along Alaska's Great River." People driving the Klondike Highway pass more than two feet of the whitish grit exposed in road cuts on their journey through the Yukon Territory... Froese and Jensen traveled in the Yukon to a branch of...

Explanation: A gaze across a cosmic skyscape, this telescopic mosaic reveals the continuous beauty of things that are. The evocative scene spans some 6 degrees or 12 Full Moons in planet Earth's sky. At the left, folds of red, glowing gas are a small part of an immense, 300 light-year wide arc. Known as Barnard's loop, the structure is too faint to be seen with the eye, shaped by long gone supernova explosions and the winds from massive stars, and still traced by the light of hydrogen atoms. Barnard's loop lies about 1,500 light-years away roughly centered on the Great...

Explanation: Stickney Crater, the largest crater on the martian moon Phobos, is named for Chloe Angeline Stickney Hall, mathematician and wife of astronomer Asaph Hall. Asaph Hall discovered both the Red Planet's moons in 1877. Over 9 kilometers across, Stickney is nearly half the diameter of Phobos itself, so large that the impact that blasted out the crater likely came close to shattering the tiny moon. This stunning, enhanced-color image of Stickney and surroundings was recorded by the HiRISE camera onboard the Mars Reconnaissance Orbiter as it passed within some six thousand kilometers of Phobos in March of 2008. Even...

Explanation: The aftermath of a cosmic cataclysm, supernova remnant Cassiopeia A (Cas A) is a comfortable 11,000 light-years away. Light from the Cas A supernova, the death explosion of a massive star, first reached Earth just 330 years ago. Still expanding, the explosion's debris cloud spans about 15 light-years near the center of this composite image. The scene combines color data of the starry field and fainter filaments of material at optical energies with image data from the orbiting NuSTAR X-ray telescope. Mapped to false colors, the X-ray data in blue hues trace the fragmented outer ring of the expanding...

For Zack Kopplin, it all started back in 2008 with the passing of the Louisiana Science Education Act. The bill made it considerably easier for teachers to introduce creationist textbooks into the classroom. Outraged, he wrote a research paper about it for a high school English class. Nearly five years later, the 19-year-old Kopplin has become one of the fiercest — and most feared — advocates for education reform in Louisiana. We recently spoke to him to learn more about how he's making a difference.

Explanation: A gorgeous spiral galaxy some 100 million light-years distant, NGC 1309 lies on the banks of the constellation of the River (Eridanus). NGC 1309 spans about 30,000 light-years, making it about one third the size of our larger Milky Way galaxy. Bluish clusters of young stars and dust lanes are seen to trace out NGC 1309's spiral arms as they wind around an older yellowish star population at its core. Not just another pretty face-on spiral galaxy, observations of NGC 1309's recent supernova and Cepheid variable stars contribute to the calibration of the expansion of the Universe. Still, after...

Explanation: Sometimes, the Sun itself seems to dance. On just this past New Year's Eve, for example, NASA's Sun-orbiting Solar Dynamic Observatory spacecraft imaged an impressive prominence erupting from the Sun's surface. The dramatic explosion was captured in ultraviolet light in the above time lapse video covering four hours. Of particular interest is the tangled magnetic field that directs a type of solar ballet for the hot plasma as it falls back to the Sun. The scale of the disintegrating prominence is huge -- the entire Earth would easily fit under the flowing curtain of hot gas. A quiescent prominence...

Explanation: In this celestial still life composed with a cosmic brush, dusty nebula NGC 2170 shines left of image center. Reflecting the light of nearby hot stars, NGC 2170 is joined by other bluish reflection nebulae, a red emission region, many dark absorption nebulae, and a backdrop of colorful stars. Like the common household items still life painters often choose for their subjects, these clouds of gas, dust, and hot stars are also commonly found in this setting -- a massive, star-forming molecular cloud in the constellation Monoceros. The giant molecular cloud, Mon R2, is impressively close, estimated to be...

Explanation: Near the outskirts of the Small Magellanic Cloud, a satellite galaxy some 200 thousand light-years distant, lies 5 million year young star cluster NGC 602. Surrounded by natal gas and dust, NGC 602 is featured in this stunning Hubble image of the region. Fantastic ridges and swept back shapes strongly suggest that energetic radiation and shock waves from NGC 602's massive young stars have eroded the dusty material and triggered a progression of star formation moving away from the cluster's center. At the estimated distance of the Small Magellanic Cloud, the picture spans about 200 light-years, but a tantalizing...

Explanation: How common are Earth-sized planets? Quite common, according to extrapolations from new data taken by NASA's orbiting Kepler spacecraft. Current computer models are indicating that at least one in ten stars are orbited by an Earth-sized planet, making our Milky Way Galaxy the home to over ten billion Earths. Unfortunately, this estimate applies only to planets effectively inside the orbit of Mercury, making these hot-Earths poor vacation opportunities for humans. This histogram depicts the estimated fraction of stars that have close orbiting planets of various sizes. The number of Sun-like stars with Earth-like planets in Earth-like orbits is surely...

Explanation: How do clusters of galaxies form and evolve? To help find out, astronomers continue to study the second closest cluster of galaxies to Earth: the Fornax cluster, named for the southern constellation toward which most of its galaxies can be found. Although almost 20 times more distant than our neighboring Andromeda galaxy, Fornax is only about 10 percent further that the better known and more populated Virgo cluster of galaxies. Fornax has a well-defined central region that contains many galaxies, but is still evolving. It has other galaxy groupings that appear distinct and have yet to merge. Seen here,...

Explanation: Cosmic bullets pierce the outskirts of the Orion Nebula some 1500 light-years distant in this sharp infrared close-up. Blasted out by energetic massive star formation the bullets, relatively dense, hot gas clouds about ten times the size of Pluto's orbit, are blue in the false color image. Glowing with the light of ionized iron atoms they travel at speeds of hundreds of kilometers per second, their passage traced by yellowish trails of the nebula's shock-heated hydrogen gas. The cone-shaped wakes are up to a fifth of a light-year long. The detailed image was created using the 8.1 meter Gemini...