Free Republic

NGC 7822 in Cepheus Credit & Copyright: Don Goldman Explanation: Pillars of gas, dust, and young, hot stars fill the center of NGC 7822. At the edge of a giant molecular cloud toward the northern constellation Cepheus, the glowing star forming region lies about 3,000 light-years away. Within the nebula, bright edges and tantalizing shapes are highlighted in this colorful skyscape. The image includes data from both broadband and narrowband filters, mapping emission from atomic oxygen, hydrogen, and sulfur into blue, green, and red hues. The atomic emission is powered by the energetic radiation from the hot stars, whose...

Classic Orion Nebulae Credit & Copyright: Kerry-Ann Lecky Hepburn (Weather and Sky Photography) Explanation: The Great Nebula in Orion, also known as M42, is one of the most famous nebulae in the sky. The star forming region's glowing gas clouds and hot young stars are near the center of this colorful deep sky image that includes the smaller nebula M43 and dusty, bluish reflection nebulae NGC 1977 and friends on the left. Located at the edge of an otherwise invisible giant molecular cloud complex, these eye-catching nebulae represent only a small fraction of this galactic neighborhood's wealth of interstellar...

Equinox at Saturn Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA Explanation: What would Saturn's rings look like if the ring plane pointed directly at the Sun? That situation occurred earlier this month when equinox occurred on Saturn. Since the Earth is nearly in the same direction as the Sun from Saturn, the rings appeared to disappear from Earth. From the robotic Cassini spacecraft orbiting Saturn, however, the unusually illuminated ring plane could be viewed from on high. Pictured above, Saturn's rings, darker than ever seen before, were captured just a few hours before equinox on 2009 August 10....

Morning Glory Clouds Over Australia Credit & Licence: Mick Petroff; Tip Thanks: James Holmes (Cairns) Explanation: What causes these long, strange clouds? No one is sure. A rare type of cloud known as a Morning Glory cloud can stretch 1,000 kilometers long and occur at altitudes up to two kilometers high. Although similar roll clouds have been seen at specific places across the world, the ones over Burketown, Queensland Australia occur predictably every spring. Long, horizontal, circulating tubes of air might form when flowing, moist, cooling air encounters an inversion layer, an atmospheric layer where air temperature atypically increases...

Giant Cluster Bends, Breaks Images Credit: NASA, ESA, H. Lee & H. Ford (Johns Hopkins U.) Explanation: What are those strange blue objects? Many of the brightest blue images are of a single, unusual, beaded, blue, ring-like galaxy which just happens to line-up behind a giant cluster of galaxies. Cluster galaxies here typically appear yellow and -- together with the cluster's dark matter -- act as a gravitational lens. A gravitational lens can create several images of background galaxies, analogous to the many points of light one would see while looking through a wine glass at a distant street...

The Gum Nebula Credit & Copyright: Axel Mellinger Explanation: Named for Australian astronomer Colin Stanley Gum (1924-1960), The Gum Nebula is so large and close it is actually hard to see. In fact, we are only about 450 light-years from the front edge and 1,500 light-years from the back edge of this cosmic cloud of glowing hydrogen gas. Covered in this 41 degree-wide mosaic of H-alpha images, the faint emission region is otherwise easy to lose against the background of Milky Way stars. The complex nebula is thought to be a supernova remnant over a million years old, sprawling across...

The Whale and the Hockey Stick Credit & Copyright: Josef Poepsel, Stefan Binnewies (Capella Observatory) Explanation: NGC 4631 is a big beautiful spiral galaxy seen edge-on (top right) only 25 million light-years away towards the small northern constellation Canes Venatici. This galaxy's slightly distorted wedge shape suggests to some a cosmic herring and to others the popular moniker of The Whale Galaxy. Either way, it is similar in size to our own Milky Way. In this gorgeous color image, the Whale's dark interstellar dust clouds, yellowish core, and young blue star clusters are easy to spot. A companion galaxy,...

IC 1396 and Surrounding Starfield Credit & Copyright: Thomas W. Earle Explanation: Sprawling across hundreds of light-years, emission nebula IC 1396, visible on the upper right, mixes glowing cosmic gas and dark dust clouds. Stars are forming in this area, only about 3,000 light-years from Earth. This wide angle view also captures surrounding emission and absorption nebula. The red glow in IC 1396 and across the image is created by cosmic hydrogen gas recapturing electrons knocked away by energetic starlight. The dark dust clouds are dense groups of smoke-like particles common in the disks of spiral galaxies. Among the...

The Milky Way Over the Badlands Credit & Copyright: Wally Pacholka (AstroPics.com, TWAN) Explanation: Why take a picture of just the Badlands when you can take one that also shows the spectacular sky above it? Just such a picture, actually a digital stitched panorama of four images, was taken in late June near midnight, looking southwest. In the foreground, the unusual buttes of the Badlands Wall, part of the Badlands National Park in South Dakota, USA, were momentarily illuminated by flashlight during a long duration exposure of the background night sky. The mountain-like buttes visible are composed of soft...

Perseids from Perseus Credit & Copyright: Chris Peterson (Cloudbait Observatory) Explanation: Where are all of these meteors coming from? In terms of direction on the sky, the pointed answer is the constellation of Perseus. That is why the last week's meteor shower was known as the Perseids -- the meteors all appear to come from a radiant toward Perseus. Three dimensionally, however, sand-sized debris expelled from Comet Swift-Tuttle follows a well-defined orbit about our Sun, and the part of the orbit that approaches Earth is superposed in front of the Perseus. Therefore, when Earth crosses this orbit, the radiant...

Block Island Meteorite on Mars Credit: Mars Exploration Rover Mission, JPL, NASA Explanation: What is this strange rock on Mars? Sitting on a smooth plane, the rock stands out for its isolation, odd shape, large size and unusual texture. The rock was discovered by the robotic Opportunity rover rolling across Mars late last month. Pictured above, Opportunity prepares to inspect the unusual rock. After being X-rayed, poked, and chemically analyzed, the rock has now been identified by Opportunity as a fallen meteorite. Now dubbed Block Island, the meteorite has been measured to be about 2/3 of a meter across and...

Irregular Galaxy NGC 55 Credit & Copyright: Don Goldman Explanation: Irregular galaxy NGC 55 is thought to be similar to the Large Magellanic Cloud (LMC). But while the LMC is about 180,000 light-years away and is a well known satellite of our own Milky Way Galaxy, NGC 55 is more like 6 million light-years distant and is a member of the Sculptor Galaxy Group. Classified as an irregular galaxy, in deep exposures the LMC itself resembles a barred disk galaxy. However, spanning about 50,000 light-years, NGC 55 is seen nearly edge-on, presenting a flattened, narrow profile in contrast with...

Inside Barringer Meteor Crater Credit & Copyright: Tony Rowell Explanation: What happens when a meteor hits the ground? Usually nothing much, as most meteors are small, and indentations they make are soon eroded away. About 50,000 years ago, however, a large meteor created Barringer Meteor Crater in Arizona, USA. Also known simply as Meteor Crater, the resulting impact basin spans over a kilometer. Pictured above, a tour group views the inside of Barringer Crater early last year. In 1920, Barringer Crater was the first feature on Earth to be recognized as an impact crater. Today, over 100 terrestrial impact...

Saturn's Iapetus: Painted Moon Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA Explanation: What has happened to Saturn's moon Iapetus? Vast sections of this strange world are dark as coal, while others are as bright as ice. The composition of the dark material is unknown, but infrared spectra indicate that it possibly contains some dark form of carbon. Iapetus also has an unusual equatorial ridge that makes it appear like a walnut. To help better understand this seemingly painted moon, NASA directed the robotic Cassini spacecraft orbiting Saturn to swoop within 2,000 kilometers in 2007. Pictured above, from about 75,000...

Diamonds in a Cloudy Sky Credit & Copyright: Óscar Martín Mesonero (OSAE), SAROS Group Explanation: Cloudy skies over Wuhan, China hid the delicate solar corona during July's total eclipse of the Sun. Still, the Moon's silhouette was highlighted by these glistening diamonds as the total eclipse phase ended. Caused by bright sunlight streaming through dips and valleys in the irregular terrain along the Moon's edge, the effect is known as Baily's Beads, named after Francis Baily who called attention to the phenomenon in 1836. The dramatic appearance of the beads at the beginning or end of a total solar eclipse...

The Star Clusters of NGC 1313 Credit: NASA, ESA, Anne Pellerin (STScI) Explanation: Like grains of sand on a cosmic beach, individual stars of barred spiral galaxy NGC 1313 are resolved in this sharp composite from the Hubble Space Telescope's Advanced Camera for Surveys (ACS). The inner region of the galaxy is pictured, spanning about 10,000 light-years. Hubble's unique ability to distinguish individual stars in the 14 million light-year distant galaxy has been used to unravel the fate of star clusters whose bright young stars are spread through the disk of the galaxy as the clusters dissolve. The exploration of...

Galaxies in Pegasus Credit & Copyright: Dietmar Hager Explanation: This wide, sharp telescopic view reveals galaxies scattered beyond the stars at the northern boundary of the high-flying constellation Pegasus. Prominent at the upper right is NGC 7331. A mere 50 million light-years away, the large spiral is one of the brighter galaxies not included in Charles Messier's famous 18th century catalog. The disturbed looking group of galaxies at the lower left is well-known as Stephan's Quintet. About 300 million light-years distant, the quintet dramatically illustrates a multiple galaxy collision, its powerful, ongoing interactions posed for a brief cosmic snapshot. On...

Betelgeuse Resolved Credit: NaCo, VLT, ESO Explanation: The sharpest image ever of Betelgeuse shows a mammoth star that is slowly evaporating. Betelgeuse (sounds a lot like "beetle juice"), also known as Alpha Orionis, is one of the largest and brightest stars known. The star is a familiar orange fixture easily visible to the unaided eye toward the constellation of Orion. The above recent image from the Very Large Telescope in Chile resolves not only the face of Betelgeuse, but a large and previously unknown plume of surrounding gas. This plume gives fresh indications of how the massive star is shedding...

A Triple Sunrise Over Gdansk Bay Credit & Copyright: Barry & Noemi Diacon (McMaster U.) Explanation: How can the same Sun rise three times? Last month on Friday, 2009 July 10, a spectacular triple sunrise was photographed at about 4:30 am over Gdansk Bay in Gdansk, Poland. Clearly, our Sun rises only once. Some optical effect is creating at least two mirages of the Sun -- but which effect? In the vast majority of similarly reported cases, mirages of the brightest object in the frame can be traced to reflections internal to the camera taking the images. Still, the...

T Tauri: A Star is Formed Credit & Copyright: T. Rector (U. Alaska Anchorage), H. Schweiker, WIYN, NOAO, AURA, NSF Explanation: What does a star look like when it is forming? The prototypical example is the variable star T Tauri, visible as the bright orange star near the image center. The orange star centered in this remarkable telescopic skyview is T Tauri, prototype of the class of T Tauri variable stars. Surrounding T Tauri is a dusty yellow cosmic cloud named the Hind's Variable Nebula (NGC 1555/1554). Over 400 light-years away, at the edge of a molecular cloud, both star...

SN 1006 Supernova Remnant Image Credit: NASA, ESA, Zolt Levay (STScI) Explanation: A new star, likely the brightest supernova in recorded human history, lit up planet Earth's sky in the year 1006 AD. The expanding debris cloud from the stellar explosion, found in the southerly constellation of Lupus, still puts on a cosmic light show across the electromagnetic spectrum. In fact, this composite view includes X-ray data in blue from the Chandra Observatory, optical data in yellowish hues, and radio image data in red. Now known as the SN 1006 supernova remnant, the debris cloud appears to be about 60...

Hubble View: Jupiter Impact Credit: NASA, ESA, H. Hammel (Space Science Institute, Boulder, Co.), and the Jupiter Impact Team Explanation: This sprawling dark marking is Jupiter's latest impact scar, a debris plume created as a small asteroid or comet disintegrated after plunging into the gas giant's atmosphere. Located in Jupiter's south polar region, the new feature was discovered by Australian amateur astronomer Anthony Wesley on July 19. On July 23rd Wesley's discovery was followed up by the Hubble Space Telescope with its newly installed Wide Field Camera 3, creating this sharpest view of the evolving debris plume. Estimates indicate...

6 Minutes 42 Seconds Credit & Copyright: Babak Tafreshi (TWAN) Explanation: The July 22nd total solar eclipse was the longest of the 21st century. From the point of maximum eclipse along the Moon's shadow track across the Pacific Ocean, the Moon completely blocked the Sun for a total of 6 minutes and 39 seconds. But from the deck of this cruise ship the duration of the total eclipse phase was extended to a whopping 6 minutes and 42 seconds by the ship's motion along the shadow track. This panoramic view of the scene shows the shimmering solar corona in a...

A Floral Aurora Corona Credit & Copyright: Zoltan Kenwell (Infocus Imagery) Explanation: Few auroras show this level of detail. Above, a standard digital camera captured a particularly active and colorful auroral corona that occurred last week above Alberta, Canada. With a shape reminiscent of a flower, the spectacular aurora had an unusually high degree of detail. The vivid green and purple auroral colors are caused by high atmospheric oxygen and hydrogen reacting to a burst of incoming electrons. Many photogenic auroras have been triggered from a solar wind stream that recently passed the Earth. The auroras were unexpected because the...

NGC 1097: Spiral Galaxy with a Central Eye Credit: NASA, JPL-Caltech, SINGS Team (SSC) Explanation: What's happening at the center of spiral galaxy NGC 1097? No one is sure, but it likely involves a supermassive black hole. Matter falling in from a bar of stars and gas across the center is likely being heated by an extremely energetic region surrounding the central black hole. From afar, the entire central region appears in the above false-color infrared image as a mysterious eye. Near the left edge and seen in blue, a smaller companion galaxy is wrapped in the spectacular spiral...

The Big Corona Credit & Copyright: Koen van Gorp Explanation: Most photographs don't adequately portray the magnificence of the Sun's corona. Seeing the corona first-hand during a total solar eclipse is best. The human eye can adapt to see features and extent that photographic film usually cannot. Welcome, however, to the digital age. The above picture is a combination of thirty-three photographs that were digitally processed to highlight faint features of a total eclipse that occurred in March of 2006. The images of the Sun's corona were digitally altered to enhance dim, outlying waves and filaments. Shadow seekers need not...

Eclipse over Chongqing, China Credit & Copyright: Stephan Heinsius Explanation: The daytime sky grew dark, the temperature dropped, and lights came on as Chongqing, China, was plunged into the Moon's shadow during the July 22nd total solar eclipse. This serene, wide-angle view of the event looks to the east over the large, populous city from a newly constructed park. Despite thin clouds, it captures the shimmering solar corona just before the end of the eclipse total phase. This total solar eclipse occurred near Aphelion, the point in Earth's elliptical orbit farthest from the Sun, and so the Sun was near...

Jupiter's New Impact Scar Credit & Copyright: Anthony Wesley Explanation: In July of 1994 pieces of Comet Shoemaker-Levy 9 collided with planet Jupiter. The explosive impacts sent plumes of debris high into the Jovian atmosphere creating dark markings or scars, visible for a time against the cloud bands. Remarkably, 15 years later, another impact scar was discovered in the Jovian atmosphere by amateur astronomer Anthony Wesley as he examined images of the gas giant taken from his home observatory just outside Murrumbateman NSW Australia. Jupiter's south pole is at the top in this July 19 discovery image, with Jupiter rotating...

The Lagoon Nebula in Gas, Dust, and Stars Credit & Copyright: Florencio Rodil Explanation: Stars are battling gas and dust in the Lagoon Nebula but the photographers are winning. Also known as M8, this photogenic nebula is visible even without binoculars towards the constellation of Sagittarius. The energetic processes of star formation create not only the colors but the chaos. The red-glowing gas, shown on the above left in re-assigned colors, results from high-energy starlight striking interstellar hydrogen gas. The Trifid nebula is visible on the far right. The dark dust filaments that lace M8 were created in the atmospheres...

The Horsehead Nebula Credit & Copyright: Nigel Sharp (NOAO), KPNO, AURA, NSF Explanation: One of the most identifiable nebulae in the sky, the Horsehead Nebula in Orion, is part of a large, dark, molecular cloud. Also known as Barnard 33, the unusual shape was first discovered on a photographic plate in the late 1800s. The red glow originates from hydrogen gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis. The darkness of the Horsehead is caused mostly by thick dust, although the lower part of the Horsehead's neck casts a shadow to the left. Streams of...

Apollo 11: Onto a New World Credit: Apollo 11, NASA Explanation: A human first set foot on another world on July 20, 1969. This world was Earth's own Moon. In honor of today's 40th anniversary, NASA has released a digitally restored video of this milestone in human history. Pictured above is Neil Armstrong preparing to take the historic first step. On the way down the Lunar Module ladder, Armstrong released equipment which included the television camera that recorded this fuzzy image. Pictures and voice transmissions were broadcast live to a world wide audience estimated at one fifth of the world's...

From the Moon to the Earth Credit: Apollo 11, NASA Explanation: After the most famous voyage of modern times, it was time to go home. After proving that humanity has the ability to go beyond the confines of planet Earth, the first humans to walk on another world -- Neil Armstrong and Buzz Aldrin -- flew the ascent stage of their Lunar Module back to meet Michael Collins in the moon-orbiting Command and Service Module. Pictured above on 1969 July 21, the ascending spaceship was captured by Collins making its approach, with the Moon below, and Earth far in the...

Planets, Great Wall, and Solar Eclipse Credit & Copyright: Terry Cuttle Brisbane, Australia Explanation: This dramatic skyscape was recorded during the August 2008 total solar eclipse. The Moon's silhouette surrounded by a glistening solar corona hangs above the Jiayuguan Fort along the western edge of the Great Wall of China. Lined-up along the ecliptic plane, all the planets of the inner solar system, Mercury, Venus, Mars, (and Earth!) can also be seen along with Saturn and bright star Regulus, as the Moon's shadow tracks across the landscape. Beyond the Moon's shadow, outside the total eclipse track, sunlight still brightens the...

Starburst Galaxy M94 Credit & Copyright: Marcin Paciorek Explanation: Beautiful island universe M94 lies a mere 15 million light-years distant in the northern constellation of the hunting dogs, Canes Venatici. A popular target for earth-based astronomers, the face-on spiral galaxy is about 30,000 light-years across. Its remarkable features include prominent dust lanes, a bright, point-like nucleus, and a bright, bluish ring dominated by the light of young, massive stars. The massive stars in the ring are all likely less than 10 million years old, indicating the galaxy experienced a well-defined era of rapid star formation. As a result, while the...

The Hercules Cluster of Galaxies Credit & Copyright: Tony Hallas Explanation: These are galaxies of the Hercules Cluster, an archipelago of island universes a mere 500 million light-years away. Also known as Abell 2151, this cluster is loaded with gas and dust rich, star-forming spiral galaxies but has relatively few elliptical galaxies, which lack gas and dust and the associated newborn stars. The colors in this remarkably deep composite image clearly show the star forming galaxies with a blue tint and galaxies with older stellar populations with a yellowish cast. The sharp picture spans about 3/4 degree across the...

The Chameleon's Dark Nebulae Credit & Copyright: Andrey Kuznetsov Explanation: The Chameleon is a small constellation near the south celestial pole. Boasting no bright stars, it blends inconspicuously with the starry southern sky. But, taken in dark skies over Namibia, this image reveals a stunning aspect of the shy constellation -- a field of dusty nebulae and colorful stars. Blue reflection nebulae are scattered through the scene, but most eye-catching is the complex of silvery dust clouds that only faintly reflect starlight, punctuated by dense dark nebulae. The dark nebulae stand out because they block out background stars. This view...

Moons and Jupiter Credit & Copyright: Anne Riou Explanation: Earth's Moon and planet Jupiter made a beautiful pairing in the night sky late last week. This skyscape recorded on July 11 from Brittany in north western France captures the bright conjunction through a cloud bank. The clouds add drama and mystery to the scene but they were also positioned to reduce the intense moonlight. As a result, the exposure captures Jupiter's own Galilean moons (lower right) as tiny pinpricks of light, lined up and hugging both sides of the solar system's ruling gas giant. Later this week, the Moon...

Erupting Volcano Anak Krakatau Credit & Copyright: Marco Fulle (Stromboli Online) Explanation: A volcano on Krakatoa is still erupting. Perhaps most famous for the powerfully explosive eruption in 1883 that killed tens of thousands of people, ash from a violent eruption might also have temporarily altered Earth's climate as long as 1500 years ago. In 1927, eruptions caused smaller Anak Krakatau to rise from the sea, and the emerging volcanic island continues to grow at an average rate of 2 cm per day. The latest eruption of Anak Krakatau started in 2008 April and continues today. In this picture,...

The Pillars of Eagle Castle Credit & Copyright: Emanuele Colognato & Jim Wood (Backyard Skies) Explanation: What lights up this castle of star formation? The familiar Eagle Nebula glows bright in many colors at once. The above image is a composite of three of these glowing gas colors. Pillars of dark dust nicely outline some of the denser towers of star formation. Energetic light from young massive stars causes the gas to glow and effectively boils away part of the dust and gas from its birth pillar. Many of these stars will explode after several million years, returning most...

Fermi's Gamma-ray Pulsars NASA, DOE, Fermi LAT Collaboration Explanation: Born in supernovae, pulsars are spinning neutron stars, collapsed stellar cores left from the death explosions of massive stars. Traditionally identified and studied by observing their regular radio pulsations, two dozen pulsars have now been detected at extreme gamma-ray energies by the Fermi Gamma-ray Space Telescope. The detections include 16 pulsars identified by their pulsed gamma-ray emission alone. This gamma-ray all-sky map, aligned with the plane of our Milky Way Galaxy, shows the pulsar positions, with the 16 new Fermi pulsars circled in yellow (8 previously known radio pulsars are in...

WALLOPS ISLAND The escape worked beautifully. Forty minutes after sunrise Wednesday, a chubby little rocket left the pad at NASA’s facility here, climbing 7,000 feet into the cool morning air. Less than a minute later, after 16 separate pyrotechnic events, nine parachute deployments and a perfect tailwind, NASA’s newest astronaut escape pod was floating safely down toward the Atlantic off the Eastern Shore. The unpiloted test was conducted in conjunction with NASA’s Constellation Program, which is designing the Orion spacecraft to take humans to the International Space Station by 2015 and to the moon by 2020. NASA already has one...

The Dark River to Antares Credit & Copyright: Jason Jennings Explanation: Connecting the Pipe Nebula to the colorful regon near bright star Antares is a dark cloud dubbed the Dark River, flowing from the picture's left edge. Murky looking, the Dark River's appearance is caused by dust obscuring background starlight, although the dark nebula contains mostly hydrogen and molecular gas. Surrounded by dust, Antares, a red supergiant star, creates an unusual bright yellowish reflection nebula. Above it, bright blue double star Rho Ophiuchi is embedded in one of the more typical bluish reflection nebulae, while red emission nebulae are also...

The Trifid Nebula in Stars and Dust Credit & Copyright: Adam Block, Mt. Lemmon SkyCenter, U. Arizona Explanation: Unspeakable beauty and unimaginable bedlam can be found together in the Trifid Nebula. Also known as M20, this photogenic nebula is visible with good binoculars towards the constellation of Sagittarius. The energetic processes of star formation create not only the colors but the chaos. The red-glowing gas results from high-energy starlight striking interstellar hydrogen gas. The dark dust filaments that lace M20 were created in the atmospheres of cool giant stars and in the debris from supernovae explosions. Which bright young stars...

Mount Rushmore's Starry Night Credit & Copyright: Wally Pacholka (TWAN) Explanation: This starry night sky sparkles above the Black Hills of South Dakota and the United States' Mount Rushmore National Park. The historic site features enormous sculptures of four US presidents; George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln, carved into the southeast face of granite cliffs. Above the monumental symbols of the country's independence and early history, the night features stars and constellations familiar to northern skygazers around the world. Most noticeable are the stars of Ursa Major and the asterism known as the Big Dipper, almost resting...

Perihelion and Aphelion Credit & Copyright: Enrique Luque Cervigón Explanation: This year Aphelion, the point in Earth's elliptical orbit when it is farthest from the Sun, occurs tomorrow, July 4th. Of course, that doesn't affect the seasons on our fair planet. Those are determined by the tilt of Earth's axis of rotation and not Earth's distance from the Sun, so July is still winter in the south and summer in northern hemisphere. But it does mean that on July 4th the Sun will be at its smallest apparent size. This composite neatly compares two pictures of the Sun taken with...

Lyman Alpha Blob Credit: NASA / ESA, CXC, JPL-Caltech, STScI, NAOJ, J.E. Geach (Univ. Durham) et al. Illustration: NASA/CXC/M.Weiss Explanation: Dubbed a Lyman-alpha blob, an enormous cloud of hydrogen gas spans several hundred thousand light-years in this remarkable image (left), a composite of x-ray, optical, and infrared data from space and ground based observatories. The gigantic, amoeba-like structure is seen as it was when the universe was a mere 2 billion years old (about 12 billion years ago). Lyman-alpha blobs are so called because they strongly emit radiation due to the Lyman-alpha emission line of hydrogen gas. Normally, Lyman-alpha emission...

Three Galaxies in Draco Credit & Copyright: Giovanni Benintende Explanation: This intriguing trio of galaxies is sometimes called the Draco Group, located in the northern constellation of (you guessed it) Draco. From left to right are edge-on spiral NGC 5981, elliptical galaxy NGC 5982, and face-on spiral NGC 5985 -- all within this single telescopic field of view spanning a little more than half the width of the full moon. While the group is far too small to be a galaxy cluster and has not been cataloged compact group, these galaxies all do lie roughly 100 million light-years from planet...

The North America and Pelican Nebulae Credit & Copyright: Danny Lee Russell Explanation: Here are some familiar shapes in unfamiliar locations. This emission nebula on the left is famous partly because it resembles Earth's continent of North America. To the right of the North America Nebula, cataloged as NGC 7000, is a less luminous nebula that resembles a pelican dubbed the Pelican Nebula. The two emission nebula measure about 50 light-years across, are located about 1,500 light-years away, and are separated by a dark absorption cloud. This spectacular image captures the nebulas, bright ionization fronts, and fine details of...

Fresh Tiger Stripes on Saturn's Enceladus Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA Explanation: Do underground oceans vent through the tiger stripes on Saturn's moon Enceladus? Long features dubbed tiger stripes are known to be spewing ice from the moon's icy interior into space, creating a cloud of fine ice particles over the moon's South Pole and creating Saturn's mysterious E-ring. Evidence for this has come from the robot Cassini spacecraft now orbiting Saturn. Pictured above, a high resolution image of Enceladus is shown from a close flyby. The unusual surface features dubbed tiger stripes are visible on...

Sarychev Peak Volcano in Stereo Credit: Expedition 20 Crew - International Space Station, NASA Stereo Image: Patrick Vantuyne Explanation: From 400 kilometers above planet Earth, the Expedition 20 Crew onboard the International Space Station (ISS) was able to witness a remarkable event from a remarkable vantage point -- the June 12 eruption of the Sarychev Peak Volcano. The active volcano is located in Russia's Kuril Island chain, stretching to the northeast of Japan. Emphasizing the orbital perspective, this stunning color stereo view was made by combining two images from the ISS and is intended to be viewed with red/blue glasses...