Data from NASA's Great Observatories has been combined to produce this unprecedented image of the central region of the Milky Way. Near-infrared light from Hubble (yellow) outlines energetic regions where stars are being born. Infrared data from Spitzer (red) show glowing clouds of dust containing complex structures. And, X-rays from Chandra (blue and violet) reveal gas heated to millions of degrees by stellar explosion and outflows from the Galaxys supermassive black hole.

Great Lakes of Titan The existence of oceans or lakes of liquid methane on Saturn's moon Titan was predicted more than 20 years ago. But with a dense haze preventing a closer look it has not been possible to confirm their presence. Until the Cassini flyby of July 22, 2006, that is. Radar imaging data from the flyby, published this week in the journal Nature, provide convincing evidence for large bodies of liquid. This image, used on the journal's cover, gives a taste of what Cassini saw. Intensity in this colorized image is proportional to how much radar brightness is returned, or more specifically, the logarithm of the radar backscatter cross-section. The colors are not a representation of what the human eye would see. The lakes, darker than the surrounding terrain, are emphasized here by tinting regions of low backscatter in blue. Radar-brighter regions are shown in tan. The strip of radar imagery is foreshortened to simulate an oblique view of the highest latitude region, seen from a point to its west. This radar image was acquired by the Cassini radar instrument in synthetic aperture mode on July 22, 2006. The image is centered near 80 degrees north, 35 degrees west and is about 140 kilometers (84 miles) across. Smallest details in this image are about 500 meters (1,640 feet) across. Image: NASA/JPL-Caltech/USGS [high-resolution] Caption: Cassini Solstice Team

Hidden Flames This VISTA image shows the spectacular star-forming region known as the Flame Nebula, or NGC 2024, in the constellation of Orion (the Hunter) and its surroundings. In views of this evocative object in visible light the core of the nebula is completely hidden behind obscuring dust, but in this VISTA view, taken in infrared light, the cluster of very young stars at the object’s heart is revealed. The wide-field VISTA view also includes the glow of the reflection nebula NGC 2023, just below centre, and the ghostly outline of the Horsehead Nebula (Barnard 33) towards the lower right. The bright bluish star towards the right is one of the three bright stars forming the Belt of Orion. The image was created from VISTA images taken through J, H and Ks filters in the near-infrared part of the spectrum. The image shows the full area of the VISTA field and is one degree by 1.5 degrees in extent. The total exposure time was 14 minutes. Image: ESO/J. Emerson/VISTA. Acknowledgment: Cambridge Astronomical Survey Unit [high-resolution] Caption: ESO

Tri-Color Sun This composite image combines EIT images from three wavelengths (171Å, 195Å and 284Å) into one that reveals solar features unique to each wavelength. Since the EIT images come to us from the spacecraft in black and white, they are color coded for easy identification. For this image, the nearly simultaneous images from May 1998 were each given a color code (red, yellow and blue) and merged into one. Image: NASA/SOHO [high-resolution] Caption: NASA

Sparkling Galaxy Reveals Black Hole The spiral galaxy NGC 3627 is located about 30 million light years from Earth. This composite image includes X-ray data from NASA's Chandra X-ray Observatory (blue), infrared data from the Spitzer Space Telescope (red), and optical data from the Hubble Space Telescope and the Very Large Telescope (yellow). The inset shows the central region, which contains a bright X-ray source that is likely powered by material falling onto a supermassive black hole. Confirming previous Chandra results, this study finds the fraction of galaxies found to be hosting supermassive black holes is much higher than found with optical searches. This shows the ability of X-ray observations to find black holes in galaxies where relatively low-level black hole activity has either been hidden by obscuring material or washed out by the bright optical light of the galaxy. Image: NASA/CXC/Ohio State Univ./C.Grier et al.; Optical: NASA/STScI, ESO/WFI; Infrared: NASA/JPL-Caltech [high-resolution] Caption: NASA

Hollows on Mercury In the well-documented case of Eminescu's hollows, the image above provides some new insight. Though the majority of the hollows are located on and directly around the central peak, if you look closely you'll see that there are small hollows located on top of the knobby texture on the upper right side of the image. Are these hollows younger than the ones on Eminescu's central peak and floor? Are hollows currently forming in Eminescu? This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week. Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington [high-resolution] Caption: Mercury Messenger team

Really Hot Stars This unique image shows AB7, one of the highest excitation nebulae in the Magellanic Clouds (MCs), two satellite galaxies of our own Milky Way. AB7 is a binary star, consisting of one WR-star — highly evolved massive star - and a mid-age massive companion of spectral type O. These exceptional stars have very strong stellar winds: they continuously eject energetic particles — like the "solar wind" from the Sun — but some 10 to 1,000 million times more intensely than our star! These powerful winds exert an enormous pressure on the surrounding interstellar material and forcefully shape those clouds into "bubbles", well visible in the photos by their blue colour. AB7 is particularly remarkable: the associated huge nebula and HeII region indicate that this star is one of the, if not the, hottest WR-star known so far, with a surface temperature in excess of 120,000 degrees ! Just outside this nebula, a small network of green filaments is visible — they are the remains of another supernova explosion. Image: ESO [high-resolution] Caption: ESO

Merry Radio Christmas This panorama of a section of the Milky Way in the constellations of Scutum and Aquila illustrates the dynamic interplay between the birth and death of massive stars in our Galaxy. The image is a composite of a radio image constructed from observations taken in several configurations of the Very Large Array at a wavelength of 20 cm for the MAGPIS survey with mid-infrared data taken as part of the GLIMPSE survey conducted by the Spitzer Space Telescope. The radio data are coded red, the long-wavelength infrared data (at 8 micrometers) green, and the shorter wavelength infrared data blue-white; yellow regions in the image show places where both radio and infrared emission is prominent. Normal stars are brightest at the shortest wavelengths, showing up as the myriad of blue-white points. Birthsites of the youngest massive stars show as yellow clumps -- radiation from the newborn stars heats surrounding dust producing infrared emission, while the ultraviolet light from these stars separates electrons from hydrogen atoms giving rise to radio emission. More mature stars have managed to destroy the dust nearby leaving red cores surrounded by yellow, then green, shells as the temperature drops far from the stars. The prominent red arcs mark the sites where massive stars have died in titanic explosions and blasted their gas light years into space at thousands of miles per second; their radio emission is produced as electrons, accelerated to nearly the speed of light by the outward moving blast waves, spiral in the Galactic magnetic field. The diffuse green glow reveals the tiny dust particles that suffuse interstellar space along the band of the Milky Way; dark filaments superposed on this emission show regions where the gas and dust are so thick that no light can get through -- regions in which future generations of stars will form. Image: Image courtesy of NRAO/AUI and (Rick White, STScI) (Bob Becker, IGPP/LLNL & UC-Davis) (David Helfand, Columbia) [high-resolution] Caption: NRAO

Colorful Large Magellanic Cloud In commemoration of NASA's Hubble Space Telescope completing its 100,000th orbit in its 18th year of exploration and discovery, scientists at the Space Telescope Science Institute in Baltimore, Md., have aimed Hubble to take a snapshot of a dazzling region of celestial birth and renewal. Hubble peered into a small portion of the nebula near the star cluster NGC 2074 (upper, left). The region is a firestorm of raw stellar creation, perhaps triggered by a nearby supernova explosion. It lies about 170,000 light-years away near the Tarantula nebula, one of the most active star-forming regions in our Local Group of galaxies. The three-dimensional-looking image reveals dramatic ridges and valleys of dust, serpent-head "pillars of creation," and gaseous filaments glowing fiercely under torrential ultraviolet radiation. The region is on the edge of a dark molecular cloud that is an incubator for the birth of new stars. The high-energy radiation blazing out from clusters of hot young stars already born in NGC 2074 is sculpting the wall of the nebula by slowly eroding it away. Another young cluster may be hidden beneath a circle of brilliant blue gas at center, bottom. In this approximately 100-light-year-wide fantasy-like landscape, dark towers of dust rise above a glowing wall of gases on the surface of the molecular cloud. The seahorse-shaped pillar at lower, right is approximately 20 light-years long, roughly four times the distance between our Sun and the nearest star, Alpha Centauri. The region is in the Large Magellanic Cloud (LMC), a satellite of our Milky Way galaxy. It is a fascinating laboratory for observing star-formation regions and their evolution. Dwarf galaxies like the LMC are considered to be the primitive building blocks of larger galaxies. This representative color image was taken on August 10, 2008, with Hubble's Wide Field Planetary Camera 2. Red shows emission from sulfur atoms, green from glowing hydrogen, and blue from glowing oxygen. Image: NASA, ESA, and M. Livio (STScI) [high-resolution] Caption: Hubble Heritage site

Hourglass Nebula Is Watching This Hubble telescope snapshot of MyCn18, a young planetary nebula, reveals that the object has an hourglass shape with an intricate pattern of "etchings" in its walls. A planetary nebula is the glowing relic of a dying, Sun-like star. The results are of great interest because they shed new light on the poorly understood ejection of stellar matter that accompanies the slow death of Sun-like stars. According to one theory on the formation of planetary nebulae, the hourglass shape is produced by the expansion of a fast stellar wind within a slowly expanding cloud, which is denser near its equator than near its poles. Image: Raghvendra Sahai and John Trauger (JPL), the WFPC2 science team, and NASA [high-resolution] Caption: Hubble Heritage site

Canyon Details on Mars Hydrae Chasma is a deep, circular depression on Mars approximately 50 kilometers across, situated between Juventae Chasma to the north and the large canyon system Valles Marineris to the south. The Chasma has steep walls flanked by numerous landslides and a massive scarp along its southern boundary where the surface has collapsed into this depression. This closeup is of an isolated flat-topped mountain (known as a mesa) rising out of a sea of dunes located in the center of Hydrae Chasma. Darker-toned dunes, likely composed of basaltic sands, form an apron along the base of the mesa's northern margin. The western side of the mesa is gently sloping and is composed of a highly fractured light-toned rubbly base. It is overlaid by alternating light and dark layered cliff-forming units and is covered by a sediment cap containing still more dunes. The layered sequences are present only in the interior deposits and not in the walls of the Chasma. Similar deposits are located on the floors of Valles Marineris and other chasmata and may be the sediment remnants of ancient lakes formed within these canyon systems. Image: NASA/JPL/University of Arizona [high-resolution] Caption: Ginny Gulick

Star Making Waves The giant star Zeta Ophiuchi is having a "shocking" effect on the surrounding dust clouds in this infrared image from NASA's Spitzer Space Telescope. Stellar winds flowing out from this fast-moving star are making ripples in the dust as it approaches, creating a bow shock seen as glowing gossamer threads, which, for this star, are only seen in infrared light. Zeta Ophiuchi is a young, large and hot star located around 370 light-years away. It dwarfs our own sun in many ways -- it is about six times hotter, eight times wider, 20 times more massive, and about 80,000 times as bright. Even at its great distance, it would be one of the brightest stars in the sky were it not largely obscured by foreground dust clouds. This massive star is travelling at a snappy pace of about 54,000 mph (24 kilometers per second), fast enough to break the sound barrier in the surrounding interstellar material. Because of this motion, it creates a spectacular bow shock ahead of its direction of travel (to the left). The structure is analogous to the ripples that precede the bow of a ship as it moves through the water, or the sonic boom of an airplane hitting supersonic speeds. The fine filaments of dust surrounding the star glow primarily at shorter infrared wavelengths, rendered here in green. The area of the shock pops out dramatically at longer infrared wavelengths, creating the red highlights. A bright bow shock like this would normally be seen in visible light as well, but because it is hidden behind a curtain of dust, only the longer infrared wavelengths of light seen by Spitzer can reach us. Bow shocks are commonly seen when two different regions of gas and dust slam into one another. Zeta Ophiuchi, like other massive stars, generates a strong wind of hot gas particles flowing out from its surface. This expanding wind collides with the tenuous clouds of interstellar gas and dust about half a light-year away from the star, which is almost 800 times the distance from the sun to Pluto. The speed of the winds added to the star's supersonic motion result in the spectacular collision seen here. Our own sun has significantly weaker solar winds and is passing much more slowly through our galactic neighborhood so it may not have a bow shock at all. NASA's twin Voyager spacecraft are headed away from the solar system and are currently about three times farther out than Pluto. They will likely pass beyond the influence of the sun into interstellar space in the next few years, though this is a much gentler transition than that seen around Zeta Ophiuchi. For this Spitzer image, infrared light at wavelengths of 3.6 and 4.5 microns is rendered in blue, 8.0 microns in green, and 24 microns in red. Image: NASA/JPL-Caltech [high-resolution] Caption: NASA/JPL

Cygnus Loop Filaments As an end of the year finale, the National Optical Astronomy Observatory (NOAO) and WIYN partners offer this new wide-field image of the Cygnus loop. Three degrees on a side, this image covers an area of the sky about 45 times that of the full moon. But it does so without sacrificing high resolution. The image is over 600 million pixels in size, making it one of the largest astronomical images ever made. The Cygnus Loop is a large supernova remnant: the gaseous remains of a massive star that exploded long ago. It is located about 1,500 light-years from Earth in the direction of the constellation Cygnus, the Swan. Astronomers estimate the supernova explosion that produced the nebula occurred between 5,000 to 10,000 years ago. First noted in 1784 by William Herschel, it is so large that its many parts have been catalogued as separate objects, including NGC 6992, NGC 6995 and IC 1340 along the eastern (left) side of the image, NGC 6974 and NGC 6979 near the top-center, and the Veil Nebula (NGC 6960) and Pickering’s Triangle along the western (right) edge. The bright star near the western edge of the image, known as 52 Cygnus, is not associated with the supernova. The data were obtained with the NOAO Mosaic 1 camera, with observations in the Oxygen [OIII] (blue), Sulphur [S II] (green) and Hydrogen-Alpha (red) filters. When mounted on the WIYN 0.9 meter telescope the Mosaic camera has a one square degree field of view. The Cygnus Loop was observed with nine separate telescope pointings in a 3x3 grid pattern. The observations were originally obtained in 2003 by Richard Cool, while he was a graduate student at the University of Arizona, as part of a project to precisely measure the distance to the Cygnus Loop. Dr. Cool, now at the MMT Observatory in Arizona, said, “Often, astronomical research reduces images to dry tables of numerical information that we analyze in order to more deeply understand our universe. Images like this are amazing because they can remind you of the big picture and beauty that surrounds us”. In 2003 the computing power available was insufficient to process the data into a single, full-resolution color image. Nine years later, the data were re-reduced and processed by Travis Rector to create the image presented here. Dr. Rector has produced a remarkable series of color images from NOAO telescopes. They can be found at his website and on a dedicated NOAO image gallery page. Images like this demonstrate that even relatively small telescopes when equipped with modern cameras are capable of producing cutting-edge research. The 0.9 meter telescope at Kitt Peak is operated by the WIYN Consortium. It has been in operation since 1960, when the original telescope was first installed at the site now occupied by the WIYN 3.5 meter telescope. Today, the 0.9 meter is regularly used by graduate students and faculty for a variety of research projects. The WIYN 0.9 meter Observatory is a partnership including Austin Peay State University, Haverford College, Indiana University, Rochester Institute of Technology, San Francisco State University, University of Wisconsin-Madison, University of Wisconsin- Stevens Point, University of Wisconsin-Whitewater, and Wisconsin Space Grant consortium. NOAO is operated by Association of Universities for Research in Astronomy Inc. (AURA) under a cooperative agreement with the National Science Foundation. Image: T.A. Rector (University of Alaska Anchorage), Richard Cool (University of Arizona) and WIYN/NOAO/AURA/NSF [high-resolution] Caption: NOAO

Back-Lit Saturn NASA's Cassini spacecraft has delivered a glorious view of Saturn, taken while the spacecraft was in Saturn's shadow. The cameras were turned toward Saturn and the sun so that the planet and rings are backlit. (The sun is behind the planet, which is shielding the cameras from direct sunlight.) In addition to the visual splendor, this special, very-high-phase viewing geometry lets scientists study ring and atmosphere phenomena not easily seen at a lower phase. Since images like this can only be taken while the sun is behind the planet, this beautiful view is all the more precious for its rarity. The last time Cassini captured a view like this was in Sept. 2006, when it captured a mosaic processed to look like natural color, entitled "In Saturn's Shadow". In that mosaic, planet Earth put in a special appearance, making "In Saturn's Shadow" one of the most popular Cassini images to date. Earth does not appear in this mosaic as it is hidden behind the planet. Also captured in this image are two of Saturn's moons: Enceladus and Tethys. Both appear on the left side of the planet, below the rings. Enceladus is closer to the rings; Tethys is below and to the left. This view looks toward the non-illuminated side of the rings from about 19 degrees below the ring plane. Images taken using infrared, red and violet spectral filters were combined to create this enhanced-color view. The images were obtained with the Cassini spacecraft wide-angle camera on Oct. 17, 2012 at a distance of approximately 500,000 miles (800,000 kilometers) from Saturn. Image scale at Saturn is about 30 miles per pixel (50 kilometers per pixel). Image: NASA/JPL-Caltech/Space Science Institute [high-resolution] Caption: Cassini Solstice team

Planetary Nebula Ornament The NASA/ESA Hubble Space Telescope celebrates the holiday season with a striking image of the planetary nebula NGC 5189. The intricate structure of the stellar eruption looks like a giant and brightly coloured ribbon in space. Image: NASA, ESA and the Hubble Heritage Team (STScI/AURA) [high-resolution] Caption: Hubble Heritage team

Tectonics on Enceladus On Oct. 5, 2008, just after coming within 25 kilometers (15.6 miles) of the surface of Enceladus, NASA's Cassini captured this stunning mosaic as the spacecraft sped away from this geologically active moon of Saturn. Craters and cratered terrains are rare in this view of the southern region of the moon's Saturn-facing hemisphere. Instead, the surface is replete with fractures, folds, and ridges—all hallmarks of remarkable tectonic activity for a relatively small world. In this enhanced-color view, regions that appear blue-green are thought to be coated with larger grains than those that appear white or gray. Portions of the tiger stripe fractures, or sulci, are visible along the terminator at lower right, surrounded by a circumpolar belt of mountains. The icy moon's famed jets emanate from at least eight distinct source regions, which lie on or near the tiger stripes. However, in this view, the most prominent feature is Labtayt Sulci, the approximately one-kilometer (0.6 miles) deep northward-trending chasm located just above the center of the mosaic. Near the top, the conspicuous ridges are Ebony and Cufa Dorsae. This false-color mosaic was created from 28 images obtained at seven footprints, or pointing positions, by Cassini's narrow-angle camera. At each footprint, four images using filters sensitive to ultraviolet, visible and infrared light (spanning wavelengths from 338 to 930 nanometers) were combined to create the individual frames. The mosaic is an orthographic projection centered at 64.49 degrees south latitude, 283.87 west longitude, and it has an image scale of 196 kilometers (122.5 miles) per pixel. The original images ranged in resolution from 180 meters (594 feet) to 288 meters (950 feet) per pixel and were acquired at distances ranging from 30,000 to 48,000 kilometers (18,750 to 30,000 miles) as the spacecraft receded from Enceladus. The view was acquired at a Sun-Enceladus-spacecraft, or phase, angle of 73 degrees. Image: NASA/JPL/Space Science Institute [high-resolution] Caption: NASA

Painted Swan Nebula Astronomers using data from ESO's Very Large Telescope (VLT), at the Paranal Observatory in Chile, have made an impressive composite of the nebula Messier 17, also known as the Omega Nebula or the Swan Nebula. The painting-like image shows vast clouds of gas and dust illuminated by the intense radiation from young stars. The image shows a central region about 15 light-years across, although the entire nebula is even larger, about 40 light-years in total. Messier 17 is in the constellation of Sagittarius (the Archer), about 6000 light-years from Earth. It is a popular target for amateur astronomers, who can obtain good quality images using small telescopes. These deep VLT observations were made at near-infrared wavelengths with the ISAAC instrument. The filters used were J (1.25 µm, shown in blue), H (1.6 µm, shown in green), and K (2.2 µm, shown in red). In the centre of the image is a cluster of massive young stars whose intense radiation makes the surrounding hydrogen gas glow. To the lower right of the cluster is a huge cloud of molecular gas. At visible wavelengths, dust grains in the cloud obscure our view, but by observing in infrared light, the glow of the hydrogen gas behind the cloud can be seen shining faintly through. Hidden in this region, which has a dark reddish appearance, the astronomers found the opaque silhouette of a disc of gas and dust. Although it is small in this image, the disc has a diameter of about 20 000 AU, dwarfing our Solar System (1 AU is the distance between the Earth and the Sun). It is thought that this disc is rotating and feeding material onto a central protostar — an early stage in the formation of a new star. Image: ESO/R. Chini [high-resolution] Caption: ESO

Galactic Pinwheel A nearly perfect ring of hot, blue stars pinwheels about the yellow nucleus of an unusual galaxy known as Hoag's Object. This image from NASA's Hubble Space Telescope captures a face-on view of the galaxy's ring of stars, revealing more detail than any existing photo of this object. The image may help astronomers unravel clues on how such strange objects form. The entire galaxy is about 120,000 light-years wide, which is slightly larger than our Milky Way Galaxy. The blue ring, which is dominated by clusters of young, massive stars, contrasts sharply with the yellow nucleus of mostly older stars. What appears to be a "gap" separating the two stellar populations may actually contain some star clusters that are almost too faint to see. Curiously, an object that bears an uncanny resemblance to Hoag's Object can be seen in the gap at the one o'clock position. The object is probably a background ring galaxy. Ring-shaped galaxies can form in several different ways. One possible scenario is through a collision with another galaxy. Sometimes the second galaxy speeds through the first, leaving a "splash" of star formation. But in Hoag's Object there is no sign of the second galaxy, which leads to the suspicion that the blue ring of stars may be the shredded remains of a galaxy that passed nearby. Some astronomers estimate that the encounter occurred about 2 to 3 billion years ago. This unusual galaxy was discovered in 1950 by astronomer Art Hoag. Hoag thought the smoke-ring-like object resembled a planetary nebula, the glowing remains of a Sun-like star. But he quickly discounted that possibility, suggesting that the mysterious object was most likely a galaxy. Observations in the 1970s confirmed this prediction, though many of the details of Hoag's galaxy remain a mystery. The galaxy is 600 million light-years away in the constellation Serpens. The Wide Field and Planetary Camera 2 took this image on July 9, 2001. Image: NASA and The Hubble Heritage Team (STScI/AURA) Acknowledgment: Ray A. Lucas (STScI/AURA) [high-resolution] Caption: Hubble Heritage Team

Shooting Star From Space This astronaut photograph, taken from the International Space Station while over China (approximately 400 kilometers to the northwest of Beijing), provides the unusual perspective of looking down on a meteor as it passes through the atmosphere. The image was taken on August 13, 2011, during the Perseid Meteor Shower that occurs every August. Image: NASA [high-resolution] Caption: NASA

Giant Star Factory Stars are sometimes born in the midst of chaos. About 3 million years ago in the nearby galaxy M33, a large cloud of gas spawned dense internal knots which gravitationally collapsed to form stars. NGC 604 was so large, however, it could form enough stars to make a globular cluster. Many young stars from this cloud are visible in this image from the Hubble Space Telescope, along with what is left of the initial gas cloud. Some stars were so massive they have already evolved and exploded in a supernova. The brightest stars that are left emit light so energetic that they create one of the largest clouds of ionized hydrogen gas known, comparable to the Tarantula Nebula in our Milky Way's close neighbor, the Large Magellanic Cloud. Image: NASA [high-resolution] Caption: NASA

5 Galaxy Pile-Up A clash among members of a famous galaxy quintet reveals an assortment of stars across a wide colour range, from young, blue stars to aging, red stars. This portrait of Stephan's Quintet, also known as the Hickson Compact Group 92, was taken by the new Wide Field Camera 3 (WFC3) aboard the NASA/ESA Hubble Space Telescope. Stephan's Quintet, as the name implies, is a group of five galaxies. The name, however, is a bit of a misnomer. Studies have shown that group member NGC 7320, at upper left, is actually a foreground galaxy that is about seven times closer to Earth than the rest of the group. Three of the galaxies have distorted shapes, elongated spiral arms, and long, gaseous tidal tails containing myriad star clusters, proof of their close encounters. These interactions have sparked a frenzy of star birth in the central pair of galaxies. This drama is being played out against a rich backdrop of faraway galaxies. The image, taken in visible and near-infrared light, showcases WFC3's broad wavelength range. The colours trace the ages of the stellar populations, showing that star birth occurred at different epochs, stretching over hundreds of millions of years. The camera's infrared vision also peers through curtains of dust to see groupings of stars that cannot be seen in visible light. NGC 7319, at top right, is a barred spiral with distinct spiral arms that follow nearly 180 degrees back to the bar. The blue specks in the spiral arm at the top of NGC 7319 and the red dots just above and to the right of the core are clusters of many thousands of stars. Most of the Quintet is too far away even for Hubble to resolve individual stars. Continuing clockwise, the next galaxy appears to have two cores, but it is actually two galaxies, NGC 7318A and NGC 7318B. Encircling the galaxies are young, bright blue star clusters and pinkish clouds of glowing hydrogen where infant stars are being born. These stars are less than 10 million years old and have not yet blown away their natal cloud. Far away from the galaxies, at right, is a patch of intergalactic space where many star clusters are forming. NGC 7317, at bottom left, is a normal-looking elliptical galaxy that is less affected by the interactions. Sharply contrasting with these galaxies is the dwarf galaxy NGC 7320 at upper left. Bursts of star formation are occurring in the galaxy's disc, as seen by the blue and pink dots. In this galaxy, Hubble can resolve individual stars, evidence that NGC 7320 is closer to Earth. NGC 7320 is 40 million light-years from Earth. The other members of the Quintet reside about 300 million light-years away in the constellation Pegasus. These more distant members are markedly redder than the foreground galaxy, suggesting that older stars reside in their cores. The stars' light also may be further reddened by dust stirred up in the encounters. Spied by Edouard M. Stephan in 1877, Stephan's Quintet is the first compact group ever discovered. WFC3 observed the Quintet in July and August 2009. The composite image was made by using filters that isolate light from the blue, green and infrared portions of the spectrum, as well as emission from ionised hydrogen. These Hubble observations are part of the Hubble Servicing Mission 4 Early Release Observations. NASA astronauts installed the WFC3 camera during a servicing mission in May to upgrade and repair the 19-year-old Hubble telescope. Image: NASA, ESA and the Hubble SM4 ERO Team [high-resolution] Caption: Hubble Heritage Team

Evaporating Rocks on Mercury The bright material on the floor of Kertész crater is not the water ice recently confirmed to be in craters near Mercury's poles, but it might well be behaving as ice would on another planet. Mercury's daytime temperatures are so hot at most latitudes that rocks that would be stable at other places in the Solar System may essentially evaporate on Mercury. That is one theory for the formation of these bright, irregular features known as hollows seen here and in many other craters on Mercury. This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week. Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington [high-resolution] Caption: Mercury MESSENGER Team

Lonely Planetary Nebula Located in a relatively vacant region of space about 4200 light-years away and difficult to see using an amateur telescope, the lonesome planetary nebula NGC 7354 is often overlooked. However, thanks to this image captured by the NASA/ESA Hubble Space Telescope we are able to see this brilliant ball of smoky light in spectacular detail. Just as shooting stars are not actually stars and lava lamps do not actually contain lava, planetary nebulae have nothing to do with planets. The name was coined by Sir William Herschel because when he first viewed a planetary nebula through a telescope, he could only identify a hazy smoky sphere, similar to gaseous planets such as Uranus. The name has stuck even though modern telescopes make it obvious that these objects are not planets at all, but the glowing gassy outer layers thrown off by a hot dying star. It is believed that winds from the central star play an important role in determining the shape and morphology of planetary nebulae. The structure of NGC 7354 is relatively easy to distinguish. It consists of a circular outer shell, an elliptical inner shell, a collection of bright knots roughly concentrated in the middle and two symmetrical jets shooting out from either side. Research suggests that these features could be due to a companion central star, however the presence of a second star in NGC 7354 is yet to be confirmed. NGC 7354 resides in Cepheus, a constellation named after the mythical King Cepheus of Aethiopia and is about half a light-year in diameter. A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by contestant Bruno Conti. Image: ESA/Hubble & NASA [high-resolution] Caption: Hubble Heritage site

Star Formation in Carina The spectacular star-forming Carina Nebula has been captured in great detail by the VLT Survey Telescope at ESO’s Paranal Observatory. This picture was taken with the help of Sebastián Piñera, President of Chile, during his visit to the observatory on 5 June 2012 and released on the occasion of the new telescope’s inauguration in Naples on 6 December 2012. Image: ESO. Acknowledgement: VPHAS+ Consortium/Cambridge Astronomical Survey Unit [high-resolution] Caption: ESO

Winter Mars Craters The high-resolution stereo camera on ESA’s Mars Express imaged the Charitum Montes region of the Red Planet on 18 June, near to Gale crater and the Argyre basin featured in our October and November image releases. The brighter features, giving the image an ethereal winter-like feel in the colour images, are surfaces covered with seasonal carbon dioxide frost.

Charitum Montes are a large group of rugged mountains extending over almost 1000 km and bounding the southernmost rim of the Argyre impact basin. They can be seen from Earth through larger telescope and were named by Eugène Michel Antoniadi (1870–1944) in his 1929 work La Planète Mars. The images in this release all show the region’s old and highly-sculpted terrain, pockmarked with many large craters, all of which have been substantially filled in. The whole region is dusted with brighter carbon dioxide frost. Image: ESA/DLR/FU Berlin (G. Neukum) [high-resolution] Caption: ESA

Infrared Orion Looking like a pair of eyeglasses only a rock star would wear, this nebula brings into focus a murky region of star formation. NASA's Spitzer Space Telescope exposes the depths of this dusty nebula with its infrared vision, showing stellar infants that are lost behind dark clouds when viewed in visible light. Best known as Messier 78, the two round greenish nebulae are actually cavities carved out of the surrounding dark dust clouds. The extended dust is mostly dark, even to Spitzer's view, but the edges show up in mid-wavelength infrared light as glowing, red frames surrounding the bright interiors. Messier 78 is easily seen in small telescopes in the constellation of Orion, just to the northeast of Orion's belt, but looks strikingly different, with dominant, dark swaths of dust. Spitzer's infrared eyes penetrate this dust, revealing the glowing interior of the nebulae. The light from young, newborn stars are starting to carve out cavities within the dust, and eventually, this will become a larger nebula like the "green ring" imaged by Spitzer. A string of baby stars that have yet to burn their way through their natal shells can be seen as red pinpoints on the outside of the nebula. Eventually these will blossom into their own glowing balls, turning this two-eyed eyeglass into a many-eyed monster of a nebula. This is a three-color composite that shows infrared observations from two Spitzer instruments. Blue represents 3.6- and 4.5-micron light, and green shows light of 5.8 and 8 microns, both captured by Spitzer's infrared array camera. Red is 24-micron light detected by Spitzer's multiband imaging photometer. Image: NASA/JPL-Caltech [high-resolution] Caption: NASA

Galactic Bullseye Bright pink nebulae almost completely encircle a spiral galaxy in this NASA/ESA Hubble Space Telescope image of NGC 922. The ring structure and the galaxy’s distorted spiral shape result from a smaller galaxy scoring a cosmic bullseye, hitting the centre of NGC 922 some 330 million years ago. In Hubble’s image, NGC 922 clearly reveals itself not to be a normal spiral galaxy. The spiral arms are disrupted, a stream of stars extends out towards the top of the image, and a bright ring of nebulae encircles the core. Observing with NASA’s Chandra X-ray Observatory reveals more chaos in the form of ultraluminous X-ray sources dotted around the galaxy. NGC 922’s current unusual form is a result of a cosmic bullseye millions of years ago. A smaller galaxy, catalogued as 2MASXI J0224301-244443, plunged right through the heart of NGC 922 and shot out the other side. In wide-field views of the NGC 922, the small interloper can be still be seen shooting away from the scene of the crash. As the small galaxy passed through the middle of NGC 922, it set up ripples that disrupted the clouds of gas, and triggered the formation of new stars whose radiation then lit up the remaining gas. The bright pink colour of the resulting nebulae is a characteristic sign of this process, and it is caused by excited hydrogen gas (the dominant element in interstellar gas clouds). This process of excitation and emission of light by gases is similar to that in neon signs. In theory, if two galaxies are aligned just right, with the small one passing through the centre of the larger one, the ring of nebulae should form a perfect circle, but more often the two galaxies are slightly off kilter, leading to a circle that, like this one, is noticeably brighter on one side than the other. These objects, called collisional ring galaxies, are relatively rare in our cosmic neighbourhood. Although galaxy collisions and mergers are commonplace, the precise alignment and ratio of sizes necessary to form a ring like this is not, and the ring-like phenomenon is also thought to be relatively short-lived. The chances of seeing one of these galaxies nearby is therefore quite low. Despite the immense number of galaxies in the Universe, this is one of only a handful known in our cosmic neighbourhood (the Cartwheel Galaxy, see potw1036a, being the most famous example). Observations of the more distant Universe (where we see further into the past) show that these rings were more common in the past, however. Hubble’s image of NGC 922 consists of a series of exposures taken in visible light with Hubble’s Wide Field Camera 3, and in visible and near-infrared light with the Wide Field and Planetary Camera 2. Image: NASA, ESA. Acknowledgement: Nick Rose [high-resolution] Caption: Hubble Heritage team

The Sun's Inner Atmosphere This combined image from Nov. 8-9, 2012, shows the sun's innermost atmosphere as seen by the Solar Dynamics Observatory (SDO) inside a larger image provided by the Solar and Heliospheric Observatory (SOHO). A coronal mass ejection can be seen traveling away from the sun in the upper right corner. Scientists can compare the images to correlate what's happening close to the sun with what happens further away. Image: ESA/NASA [high-resolution] Caption: NASA

Glittery Galaxy The brilliant cascade of stars through the middle of this image is the galaxy ESO 318-13 as seen by the NASA/ESA Hubble Space Telescope. Despite being located millions of light-years from Earth, the stars captured in this image are so bright and clear you could almost attempt to count them. Although ESO 318-13 is the main event in this image, it is sandwiched between a vast collection of bright celestial objects. Several stars near and far dazzle in comparison to the neat dusting contained within the galaxy. One that particularly stands out is located near the centre of the image, and looks like an extremely bright star located within the galaxy. This is, however, a trick of perspective. The star is located in the Milky Way, our own galaxy, and it shines so brightly because it is so much closer to us than ESO 318-13. There are also a number of tiny glowing discs scattered throughout the frame that are more distant galaxies. In the top right corner, an elliptical galaxy can be clearly seen, a galaxy which is much larger but more distant than ESO 318-13. More interestingly, peeking through the ESO 318-13, near the right-hand edge of the image, is a distant spiral galaxy. Galaxies are largely made up of empty space; the stars within them only take up a small volume, and providing a galaxy is not too dusty, it can be largely transparent to light coming from the background. This makes overlapping galaxies like these quite common. One particularly dramatic example of this phenomenon is the galaxy pair NGC 3314 (heic1208). Image: ESA/Hubble & NASA [high-resolution] Caption: Hubble Heritage team

Saturn and Tiny Tethys Tethys may not be tiny by normal standards, but when it is captured alongside Saturn, it can't help but seem pretty small. Even Saturn's rings appear to dwarf Tethys (660 miles, or 1,062 kilometers across), which is in the upper left of the image, although scientists believe the moon to be many times more massive than the entire ring system combined. This view looks toward the unilluminated side of the rings from about 18 degrees below the ringplane. The image was taken in green light with the Cassini spacecraft wide-angle camera on Aug. 19, 2012. The view was acquired at a distance of approximately 1.5 million miles (2.4 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 63 degrees. Image scale is 86 miles (138 kilometers) per pixel. Image: NASA/JPL-Caltech/Space Science Institute [high-resolution] Caption: NASA

Sinuous Filament of Cosmic Dust This image from the APEX telescope, of part of the Taurus Molecular Cloud, shows a sinuous filament of cosmic dust more than ten light-years long. In it, newborn stars are hidden, and dense clouds of gas are on the verge of collapsing to form yet more stars. The cosmic dust grains are so cold that observations at submillimetre wavelengths, such as these made by the LABOCA camera on APEX, are needed to detect their faint glow. This image shows two regions in the cloud: the upper-right part of the filament shown here is Barnard 211, while the lower-left part is Barnard 213. The submillimetre-wavelength observations from the LABOCA camera on APEX, which reveal the heat glow of the cosmic dust grains, are shown here in orange tones. They are superimposed on a visible-light image of the region, which shows the rich background of stars. The bright star above the filament is φ Tauri. Image: ESO/APEX (MPIfR/ESO/OSO)/A. Hacar et al./Digitized Sky Survey 2. Acknowledgment: Davide De Martin [high-resolution] Caption: ESO

Eskimo Nebula In its first glimpse of the heavens following the successful December 1999 servicing mission, NASA's Hubble Space Telescope has captured a majestic view of a planetary nebula, the glowing remains of a dying, Sun-like star. This stellar relic, first spied by William Herschel in 1787, is nicknamed the "Eskimo" Nebula (NGC 2392) because, when viewed through ground-based telescopes, it resembles a face surrounded by a fur parka. In this Hubble telescope image, the "parka" is really a disk of material embellished with a ring of comet-shaped objects, with their tails streaming away from the central, dying star. The Eskimo's "face" also contains some fascinating details. Although this bright central region resembles a ball of twine, it is, in reality, a bubble of material being blown into space by the central star's intense "wind" of high-speed material. The planetary nebula began forming about 10,000 years ago, when the dying star began flinging material into space. The nebula is composed of two elliptically shaped lobes of matter streaming above and below the dying star. In this photo, one bubble lies in front of the other, obscuring part of the second lobe. Scientists believe that a ring of dense material around the star's equator, ejected during its red giant phase, created the nebula's shape. This dense waist of material is plodding along at 72,000 miles per hour (115,000 kilometers per hour), preventing high-velocity stellar winds from pushing matter along the equator. Instead, the 900,000-mile-per-hour (1.5-million-kilometer-per-hour) winds are sweeping the material above and below the star, creating the elongated bubbles. The bubbles are not smooth like balloons but have filaments of denser matter. Each bubble is about 1 light-year long and about half a light-year wide. Scientists are still puzzled about the origin of the comet-shaped features in the "parka." One possible explanation is that these objects formed from a collision of slow- and fast-moving gases. The Eskimo Nebula is about 5,000 light-years from Earth in the constellation Gemini. The picture was taken Jan. 10 and 11, 2000, with the Wide Field and Planetary Camera 2. The nebula's glowing gases produce the colors in this image: nitrogen (red), hydrogen (green), oxygen (blue), and helium (violet). Image: NASA, Andrew Fruchter and the ERO Team [Sylvia Baggett (STScI), Richard Hook (ST-ECF), Zoltan Levay (STScI)] [high-resolution] Caption: Hubble Heritage site

Height on the Moon This new topographic map, from Arizona State University in Tempe, shows the surface shape and features over nearly the entire Moon with a pixel scale close to 100 m (328 feet). A single measure of elevation (one pixel) is about the size of two football fields placed side-by-side. This map was created based on data acquired by NASA's Lunar Reconnaissance Orbiter's (LRO) WAC, which is part of the LROC imaging system. The LROC imaging system consists of two Narrow Angle Cameras (NACs) to provide high-resolution images, and the WAC to provide 100-m resolution images in seven color bands over a 57-km (35-mile) swath. Image: GSFC/DLR/ASU [high-resolution] Caption: NASA

Jets of Hercules Spectacular jets powered by the gravitational energy of a supermassive black hole in the core of the elliptical galaxy Hercules A illustrate the combined imaging power of two of astronomy's cutting-edge tools, the Hubble Space Telescope's Wide Field Camera 3, and the recently upgraded Karl G. Jansky Very Large Array (VLA) radio telescope in New Mexico. Some two billion light-years away, the yellowish elliptical galaxy in the center of the image appears quite ordinary as seen by Hubble in visible wavelengths of light. The galaxy is roughly 1,000 times more massive than the Milky Way and harbors a 2.5-billion-solar-mass central black hole that is 1,000 times more massive than the black hole in the Milky Way. But the innocuous-looking galaxy, also known as 3C 348, has long been known as the brightest radio-emitting object in the constellation Hercules. Emitting nearly a billion times more power in radio wavelengths than our Sun, the galaxy is one of the brightest extragalactic radio sources in the entire sky. The VLA radio data reveal enormous, optically invisible jets that, at one-and-a-half million light-years wide, dwarf the visible galaxy from which they emerge. The jets are very-high-energy plasma beams, subatomic particles and magnetic fields shot at nearly the speed of light from the vicinity of the black hole. The outer portions of both jets show unusual ring-like structures suggesting a history of multiple outbursts from the supermassive black hole at the center of the galaxy. The innermost parts of the jets are not visible because of the extreme velocity of the material, which causes relativistic effects that beam the light away from us. Far from the galaxy, the jets become unstable and break up into the rings and wisps. The entire radio source is surrounded by a very hot, X-ray-emitting cloud of gas, not seen in this optical-radio composite. Hubble's view of the field also shows a companion elliptical galaxy very close to the center of the optical-radio source, which may be merging with the central galaxy. Several other elliptical and spiral galaxies that are visible in the Hubble data may be members of a cluster of galaxies. Hercules A is by far the brightest and most massive galaxy in the cluster. Image: NASA, ESA, S. Baum and C. O'Dea (RIT), R. Perley and W. Cotton (NRAO/AUI/NSF), and the Hubble Heritage Team (STScI/AURA) [high-resolution] Caption: Hubble Heritage Team

The Great Attractor This image shows the central region of the Great Attractor at the original resolution of the WFI. Note the strong warping of the galaxy to the left of the center, which may be caused by gravitational interaction with one or both of the bright galaxies that are seen above and below it. The field shown measures about 12 x 12 arcmin 2. Five exposures each were made in blue (B-band filter; 5 x 300 sec), red (R-band filter; 5 x 180 sec) and near-infrared (narrow-band filter centered at 816 nm; 5 x 240 sec) light and combined into a false-colour composite by using blue, green, and red colour for the three images, respectively. A logarithmic intensity scale is used to better show the inner as well as the outer regions of the galaxies in this field. Image: ESO [high-resolution] Caption: ESO

Galaxy Rose In celebration of the 21st anniversary of the Hubble Space Telescope's deployment into space, astronomers at the Space Telescope Science Institute in Baltimore, Md., pointed Hubble's eye to an especially photogenic group of interacting galaxies called Arp 273. The larger of the spiral galaxies, known as UGC 1810, has a disk that is tidally distorted into a rose-like shape by the gravitational tidal pull of the companion galaxy below it, known as UGC 1813. A swath of blue jewels across the top is the combined light from clusters of intensely bright and hot young blue stars. These massive stars glow fiercely in ultraviolet light. The smaller, nearly edge-on companion shows distinct signs of intense star formation at its nucleus, perhaps triggered by the encounter with the companion galaxy. A series of uncommon spiral patterns in the large galaxy is a tell-tale sign of interaction. The large, outer arm appears partially as a ring, a feature seen when interacting galaxies actually pass through one another. This suggests that the smaller companion actually dived deep, but off-center, through UGC 1810. The inner set of spiral arms is highly warped out of the plane with one of the arms going behind the bulge and coming back out the other side. How these two spiral patterns connect is still not precisely known. A possible mini-spiral may be visible in the spiral arms of UGC 1810 to the upper right. It is noticeable how the outermost spiral arm changes character as it passes this third galaxy, from smooth with lots of old stars (reddish in color) on one side to clumpy and extremely blue on the other. The fairly regular spacing of the blue star-forming knots fits with what is seen in the spiral arms of other galaxies and is predictable based on instabilities in the gas contained within the arm. The larger galaxy in the UGC 1810 - UGC 1813 pair has a mass that is about five times that of the smaller galaxy. In unequal pairs such as this, the relatively rapid passage of a companion galaxy produces the lopsided or asymmetric structure in the main spiral. Also in such encounters, the starburst activity typically begins in the minor galaxies earlier than in the major galaxies. These effects could be due to the fact that the smaller galaxies have consumed less of the gas present in their nucleus, from which new stars are born. Arp 273 lies in the constellation Andromeda and is roughly 300 million light-years away from Earth. The image shows a tenuous tidal bridge of material between the two galaxies that are separated by tens of thousands of light-years from each other. The interaction was imaged on December 17, 2010, with Hubble's Wide Field Camera 3 (WFC3). This Hubble image is a composite of data taken with three separate filters on WFC3 that allow a broad range of wavelengths covering the ultraviolet, blue, and red portions of the spectrum. Image: NASA, ESA, and the Hubble Heritage Team (STScI/AURA) [high-resolution] Caption: Hubble Heritage Team

Pac-Man Moons of Saturn Scientists with NASA's Cassini mission have spotted two features shaped like the 1980s video game icon "Pac-Man" on moons of Saturn. One was observed on the moon Mimas in 2010 and the latest was observed on the moon Tethys. The pattern appears in thermal data obtained by Cassini's composite infrared spectrometer, with warmer areas making up the Pac-Man shape. Scientists saw the Tethys Pac-Man in data obtained on Sept. 14, 2011, where daytime temperatures inside the mouth of Pac-Man were seen to be cooler than their surroundings by 29 degrees Fahrenheit (15 kelvins). The warmest temperature recorded was a chilly minus 300 degrees Fahrenheit (90 kelvins). The Mimas Pac-Man was seen in data from Feb. 13, 2010. (For more information, see PIA12867.) The high temperature at Tethys is actually slightly cooler than the warmest temperature at Mimas (about minus 290 degrees Fahrenheit or 95 kelvins). One version of the image pegs white to be the hottest temperatures on both moons - minus 290 degrees Fahrenheit (95 kelvins) on Mimas and minus 300 degrees Fahrenheit (90 kelvins) on Tethys. Another version shows the minus 290 degrees Fahrenheit (95 kelvins) as white on both moons, revealing a subtler temperature variation on Tethys. At Tethys, unlike Mimas, the Pac-Man pattern can also be seen subtly in visible-light images of the surface, as a dark lens-shaped region. This brightness variation was first noticed in an image from NASA's Voyager spacecraft in 1980. Scientists theorize that the Pac-Man thermal shape on the Saturnian moons occurs because high-energy electrons bombard low latitudes on the side of the moon that faces forward as it orbits around Saturn, turning a fluffy surface into hard-packed ice. As a result, the altered surface does not heat as rapidly in the sunshine or cool down as quickly at night as the rest of the surface, similar to how a boardwalk at the beach feels cooler during the day but warmer at night than the nearby sand. Finding another PacMan on Tethys confirms that high-energy electrons can dramatically alter the surface of an icy moon. Also, because the altered region on Tethys, unlike on Mimas, is also bombarded by icy particles from Enceladus' plumes, it implies the surface alteration is occurring more quickly than its recoating by plume particles. Image: NASA/JPL-Caltech/GSFC/SWRI [high-resolution] Caption: NASA

All-Wavelengths Galactic Center In celebration of the International Year of Astronomy 2009, NASA's Great Observatories -- the Hubble Space Telescope, the Spitzer Space Telescope, and the Chandra X-ray Observatory -- have collaborated to produce an unprecedented image of the central region of our Milky Way galaxy. In this spectacular image, observations using infrared light and X-ray light see through the obscuring dust and reveal the intense activity near the galactic core. Note that the center of the galaxy is located within the bright white region to the right of and just below the middle of the image (labeled Sagitarrius A when you roll your mouse over the above composite image). The entire image width covers about one-half a degree, about the same angular width as the full moon. Each telescope's contribution is presented in a different color: Yellow represents the near-infrared observations of Hubble. They outline the energetic regions where stars are being born as well as reveal hundreds of thousands of stars. Red represents the infrared observations of Spitzer. The radiation and winds from stars create glowing dust clouds that exhibit complex structures from compact, spherical globules to long, stringy filaments. Blue and violet represents the X-ray observations of Chandra. X-rays are emitted by gas heated to millions of degrees by stellar explosions and by outflows from the supermassive black hole in the galaxy's center. The bright blue blob on the left side of the full field image is emission from a double star system containing either a neutron star or a black hole. When these views are brought together, this composite image provides one of the most detailed views ever of our galaxy's mysterious core. Image: X-ray: NASA/CXC/UMass/D. Wang et al.; Optical: NASA/ESA/STScI/D.Wang et al.; IR: NASA/JPL-Caltech/SSC/S.Stolovy [high-resolution] Caption: Chandra space telescope

Comet's McNaught Spectacular Comet McNaught setting behind Mount Paranal, in January 2007. Image: S. Deiries/ESO [high-resolution] Caption: ESO

Celestial Finger Painting This colour-composite image was obtained by FORS1 on ANTU. It displays a sky area near the Chamaeleon I complex of bright nebulae and hot stars in the constellation of the same name, close to the southern celestial pole.This picture was taken a few days before the Paranal Inauguration and the "hand-over" to the astronomers on April 1, 1999.This colour composite photo of the Chamaeleon I area is based on six 1-min exposures obtained with VLT UT1 + FORS1 in the V, R and I bands. The sky field measures 6.8 x 11.2 arcmin2; North is up and East is left. Image: ESO [high-resolution] Caption: ESO

Winter Dunes on Mars Dunes within a crater on Mars are visible in this image. This crater is located in the Southern hemisphere where it was winter at the time this image was taken. This observation documents new seasonal processes occurring on dunes at this latitude, as well as other interesting phenomena. The bright tones are interpreted as carbon dioxide or water frost. This is generally concentrated on the east-facing slopes of the dunes, which are in shadow and therefore cooler. Some dark spots on the dunes may be areas that have defrosted more than surrounding terrain. Landslides and dark-toned streaks are seen on many of the west-facing dune slopes. The general dune morphology indicates formation by westerly winds. However, zooming in on the image shows smaller scale ripples that appear to have been formed by winds blowing from the south and north. Image: ESA/Hubble & NASA [high-resolution] Caption: Nathan Bridges & Kelly Kolb

Loose Spiral Galaxy The NASA/ESA Hubble Space Telescope has spotted the spiral galaxy ESO 499-G37, seen here against a backdrop of distant galaxies, scattered with nearby stars. The galaxy is viewed from an angle, allowing Hubble to reveal its spiral nature clearly. The faint, loose spiral arms can be distinguished as bluish features swirling around the galaxy’s nucleus. This blue tinge emanates from the hot, young stars located in the spiral arms. The arms of a spiral galaxy have large amounts of gas and dust, and are often areas where new stars are constantly forming. The galaxy’s most characteristic feature is a bright elongated nucleus. The bulging central core usually contains the highest density of stars in the galaxy, where typically a large group of comparatively cool old stars are packed in this compact, spheroidal region. One feature common to many spiral galaxies is the presence of a bar running across the centre of the galaxy. These bars are thought to act as a mechanism that channels gas from the spiral arms to the centre, enhancing the star formation. Recent studies suggest that ESO 499-G37’s nucleus sits within a small bar up to a few hundreds of light-years along, about a tenth the size of a typical galactic bar. Astronomers think that such small bars could be important in the formation of galactic bulges since they might provide a mechanism for bringing material from the outer regions down to the inner ones. However, the connection between bars and bulge formation is still not clear since bars are not a universal feature in spiral galaxies. Lying in the constellation of Hydra, ESO 499-G37 is located about 59 million light-years away from the Sun. The galaxy belongs to the NGC 3175 group. ESO 499-G37 was first observed in the late seventies within the ESO/Uppsala Survey of the ESO (B) atlas. This was a joint project undertaken by the European Southern Observatory (ESO) and the Uppsala Observatory, which used the ESO 1-metre Schmidt telescope at La Silla Observatory, Chile, to map a large portion of the southern sky looking for stars, galaxies, clusters, and planetary nebulae. This picture was created from visible and infrared exposures taken with the Wide Field Channel of the Advanced Camera for Surveys. The field of view is approximately 3.4 arcminutes wide. Image: ESA/Hubble & NASA [high-resolution] Caption: NASA/ESA

Galactic Gas Bridge ESA’s Planck space telescope has made the first conclusive detection of a bridge of hot gas connecting a pair of galaxy clusters across 10 million light-years of intergalactic space. Planck’s primary task is to capture the most ancient light of the cosmos, the Cosmic Microwave Background, or CMB. As this faint light traverses the Universe, it encounters different types of structure including galaxies and galaxy clusters – assemblies of hundreds to thousands of galaxies bound together by gravity.

If the CMB light interacts with the hot gas permeating these huge cosmic structures, its energy distribution is modified in a characteristic way, a phenomenon known as the Sunyaev–Zel’dovich (SZ) effect, after the scientists who discovered it. This effect has already been used by Planck to detect galaxy clusters themselves, but it also provides a way to detect faint filaments of gas that might connect one cluster to another. In the early Universe, filaments of gaseous matter pervaded the cosmos in a giant web, with clusters eventually forming in the densest nodes. Much of this tenuous, filamentary gas remains undetected, but astronomers expect that it could most likely be found between interacting galaxy clusters, where the filaments are compressed and heated up, making them easier to spot. Planck’s discovery of a bridge of hot gas connecting the clusters Abell 399 and Abell 401, each containing hundreds of galaxies, represents one such opportunity. The presence of hot gas between the billion-light-year-distant clusters was first hinted at in X-ray data from ESA’s XMM-Newton, and the new Planck data confirm the observation. It also marks Planck’s first detection of inter-cluster gas using the SZ effect technique. By combining the Planck data with archival X-ray observations from the German satellite Rosat, the temperature of the gas in the bridge is found to be similar to the temperature of the gas in the two clusters – on the order of 80 million degrees Celsius. Early analysis suggests the gas could be mixture of the elusive filaments of the cosmic web mixed with gas originating from the clusters. A more detailed analysis and the possible detection of gas bridges connecting other clusters will help to provide a more conclusive answer. The new finding highlights the ability of Planck to probe galaxy clusters to their outskirts and beyond, examining their connection with the gas that permeates the entire Universe and from which all groups of galaxies formed. Image: Sunyaev–Zel’dovich effect: ESA Planck Collaboration; optical image: STScI Digitized Sky Survey [high-resolution] Caption: ESA

Mercury's Pie Crust Craters MESSENGER has discovered assemblages of tectonic landforms unlike any previously found on Mercury or elsewhere in the Solar System. The findings are reported in a paper led by Smithsonian scientist Thomas Watters, "Extension and contraction within volcanically buried impact craters and basins on Mercury," published in the December issue of the journal Geology. The surface of Mercury is covered with deformational landforms that formed by faulting in response to horizontal contraction or shortening as the planet's interior cooled and surface area shrank, causing blocks of crustal material to be pushed together. Contraction from cooling of Mercury's interior has been so dominant that extensional landforms caused by fault formation in response to horizontal stretching and pulling apart of crustal material had not been previously documented outside of the interiors of a few large impact basins. The MESSENGER spacecraft, in orbit around Mercury since March of last year, has revealed families of extensional troughs, or graben, that are encircled by contractional wrinkle ridges arranged in circular rings. The troughs can form complex patterns varying from the outlines of polygons inside the ridge rings to arcs that parallel the bounding ridges. "The pattern of winkle ridges and graben resembles the raised edge and cracks in a pie crust," said Watters of the Center for Earth and Planetary Studies at the National Air and Space Museum. The "pie crust" analogy also fits another notable aspect of these collections of tectonic landforms -- their association with "ghost" craters. Ghost craters are impact craters that have been flooded and buried by lava flows. The thin volcanic deposits overlying the rim of a fully buried impact crater serve to concentrate contractional forces, leading to the formation of a ridge ring that reveals the outline of the buried crater. "The special arrangement of the wrinkle ridges and graben in many of the ghost craters on Mercury is due to a combination of extensional forces from cooling and contraction of unusually thick lava flow units and contractional forces from cooling and contraction of the planet's interior," says Sean Solomon of the Columbia University's Lamont-Doherty Earth Observatory, coauthor and principal investigator of the MESSENGER mission. The eruption and rapid accumulation of very fluid lava flows into thick cooling units on a planet undergoing a high rate of global contraction may be why these systems of tectonic landforms in ghost craters on Mercury have not been seen elsewhere in the Solar System. Image: NASA/The Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/Smithsonian Institution [high-resolution] Caption: Mercury Messenger Team

Planetary Nebula Reborn These images of the planetary nebula Abell 30 show one of the clearest views ever obtained of a special phase of evolution for these objects. The inset image on the right is a close-up view of A30 showing X-ray data from NASA's Chandra X-ray Observatory in purple and Hubble Space Telescope data showing optical emission from oxygen ions in orange. On the left is a larger view showing optical and X-ray data from the Kitt Peak National Observatory and ESA's XMM-Newton, respectively. In this image the optical data show emission from oxygen (orange) and hydrogen (green and blue), and X-ray emission is colored purple. A planetary nebula -- so called because it looks like a planet when viewed with a small telescope -- is formed in the late stage of the evolution of a sun-like star. After having steadily produced energy for several billion years through the nuclear fusion of hydrogen into helium in its central region, or core, the star undergoes a series of energy crises related to the depletion of hydrogen and subsequent contraction of the core. These crises culminate in the star expanding a hundred-fold to become a red giant. Eventually the outer envelope of the red giant is ejected and moves away from the star at a relatively sedate speed of less than 100,000 miles per hour. The star meanwhile is transformed from a cool giant into a hot, compact star that produces intense ultraviolet radiation and a fast wind of particles moving at about 6 million miles per hour. The interaction of the UV radiation and the fast wind with the ejected red giant envelope creates the planetary nebula, shown by the large spherical shell in the bigger image. In rare cases, nuclear fusion reactions in the region surrounding the star's core heat the outer envelope of the star so much that it temporarily becomes a red giant again. The sequence of events -- envelope ejection followed by a fast stellar wind -- is repeated on a much faster scale than before, and a small-scale planetary nebula is created inside the original one. In a sense, the planetary nebula is reborn. Image: NASA/ESA [high-resolution] Caption: NASA

Dry Ice Spiders of Mars Have you ever played with dry ice (with leather gloves on of course!)? Perhaps you've made Halloween punch? Set a spooky scene? The fun comes from the fact that dry ice goes directly from solid to vapor, unlike water ice which melts into liquid when it gets warm. On Mars the seasonal polar caps are composed of dry ice (carbon dioxide). In the springtime as the sun shines on the ice, it turns from solid to gas and causes erosion of the surface. I enjoy the incredible diversity of forms that the erosion takes, and am studying the factors that give us "spiders", "caterpillars", or "starbursts", all colloquial words for what we rigorously name "araneiform" terrain. This particular example shows eroded channels filled with bright ice, in contrast to the muted red of the underlying ground. In the summer the ice will disappear into the atmosphere, and we will see just the channels of ghostly spiders carved in the surface. This is truly Martian terrain - this type of erosion does not take place anywhere naturally on earth because our climate is too warm. Image: NASA/JPL/University of Arizona [high-resolution] Caption: Candy Hansen/HiRISE

Stellar Stellar Cluster Like a July 4 fireworks display, a young, glittering collection of stars looks like an aerial burst. The cluster is surrounded by clouds of interstellar gas and dust—the raw material for new star formation. The nebula, located 20,000 light-years away in the constellation Carina, contains a central cluster of huge, hot stars, called NGC 3603. This environment is not as peaceful as it looks. Ultraviolet radiation and violent stellar winds have blown out an enormous cavity in the gas and dust enveloping the cluster, providing an unobstructed view of the cluster. Most of the stars in the cluster were born around the same time but differ in size, mass, temperature, and color. The course of a star's life is determined by its mass, so a cluster of a given age will contain stars in various stages of their lives, giving an opportunity for detailed analyses of stellar life cycles. NGC 3603 also contains some of the most massive stars known. These huge stars live fast and die young, burning through their hydrogen fuel quickly and ultimately ending their lives in supernova explosions. Star clusters like NGC 3603 provide important clues to understanding the origin of massive star formation in the early, distant universe. Astronomers also use massive clusters to study distant starbursts that occur when galaxies collide, igniting a flurry of star formation. The proximity of NGC 3603 makes it an excellent lab for studying such distant and momentous events. This Hubble Space Telescope image was captured in August 2009 and December 2009 with the Wide Field Camera 3 in both visible and infrared light, which trace the glow of sulfur, hydrogen, and iron. Image: NASA, ESA, R. O'Connell (University of Virginia), F. Paresce (National Institute for Astrophysics, Bologna, Italy), E. Young (Universities Space Research Association/Ames Research Center), the WFC3 Science Oversight Committee, and the Hubble Heritage Team (STScI/AURA) [high-resolution] Caption: Hubble Heritage Team

Supernova Death and New Life Supernova remnant W44 is the focus of this new image created by combining data from ESA’s Herschel and XMM-Newton space observatories. W44 is the vast purple sphere that dominates the left hand side of this image, and measures about 100 light-years across. XMM-Newton data reveal that the remnant is filled with X-ray emission from extremely hot gas. Herschel’s three-colour infrared view comprises PACS 70 and 160 micron and SPIRE 250 micron images. X-ray data from XMM-Newton’s EPIC instrument for W44 only has been added in light and dark blue to represent high- (2–8 keV) and low-energy (1.2–2 keV) X-ray emission, respectively. The field of view is about 1º across. North is towards the bottom left of the image; east is to the top right. Image: Herschel: Q. Nguyen Luong & F. Motte, HOBYS Key Program consortium, Herschel SPIRE/PACS/ESA consortia. XMM-Newton: ESA/XMM-Newton [high-resolution] Caption: ESA

Map of Tethys This global map of Saturn's moon Tethys was created using images taken during Cassini spacecraft flybys. The map is an equidistant (simple cylindrical) projection and has a scale of 293 meters (960 feet) per pixel at the equator in the full size version. The mean radius of Tethys used for projection of this map is 536.3 kilometers (333.2 miles). The resolution of the map is 32 pixels per degree. Image: NASA/JPL/Space Science Institute [high-resolution] Caption: NASA/JPL/Space Science Institute

Firefly Galaxies Luminous galaxies glow like fireflies on a dark night in this image snapped by the NASA/ESA Hubble Space Telescope. The central galaxy in this image is a gigantic elliptical galaxy designated 4C 73.08. A prominent spiral galaxy seen from "above" shines in the lower part of the image, while examples of galaxies viewed edge-on also populate the cosmic landscape. In the optical and near-infrared light captured to make this image, 4C 73.08 does not appear all that beastly. But when viewed in longer wavelengths the galaxy takes on a very different appearance. Dust-piercing radio waves reveal plumes emanating from the core, where a supermassive black hole spews out twin jets of material. 4C 73.08 is classified as a radio galaxy as a result of this characteristic activity in the radio part of the electromagnetic spectrum. Astronomers must study objects such as 4C 73.08 in multiple wavelengths in order to learn their true natures, just as seeing a firefly’s glow would tell a scientist only so much about the insect. Observing 4C 73.08 in visible light with Hubble illuminates galactic structure as well as the ages of constituent stars, and therefore the age of the galaxy itself. 4C 73.08 is decidedly redder than the prominent, bluer spiral galaxy in this image. The elliptical galaxy’s redness comes from the presence of many older, crimson stars, which shows that 4C 73.08 is older than its spiral neighbour. The image was taken using Hubble’s Wide Field Camera 3 through two filters: one which captures green light, and one which captures red and near-infrared light. Image: ESA/Hubble & NASA [high-resolution] Caption: Hubble Heritage Team

Titan Vortex Titan's swirling south-polar vortex stands out brightly against the other clouds of the south pole. Cassini is monitoring the development of the south polar vortex to help understand seasonal changes on Saturn's largest moon. For a color image of the south polar vortex on Titan, see PIA14919. For a movie of the vortex, see PIA14920. This view looks toward the trailing hemisphere of Titan (3200 miles, 5150 kilometers across). North on Titan is up and rotated 36 degrees to the left. The image was taken with the Cassini spacecraft narrow-angle camera on Aug. 31, 2012 using a spectral filter sensitive to wavelengths of near-infrared light centered at 938 nanometers. The view was acquired at a distance of approximately 750,000 miles (1.2 million kilometers) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 74 degrees. Image scale is 4 miles (7 kilometers) per pixel. Image: NASA/JPL-Caltech/Space Science Institute [high-resolution] Caption: Cassini Solstice Team

Jupiter's Spots In what's beginning to look like a case of planetary measles, a third red spot has appeared alongside its cousins — the Great Red Spot and Red Spot Jr. — in the turbulent Jovian atmosphere. This third red spot, which is a fraction of the size of the two other features, lies to the west of the Great Red Spot in the same latitude band of clouds. The new red spot was previously a white oval-shaped storm. The change to a red color indicates its swirling storm clouds are rising to heights like the clouds of the Great Red Spot. One possible explanation is that the red storm is so powerful it dredges material from deep beneath Jupiter's cloud tops and lifts it to higher altitudes where solar ultraviolet radiation — via some unknown chemical reaction — produces the familiar brick color. Detailed analysis of the visible-light images taken by Hubble's Wide Field Planetary Camera 2 on May 9 and 10, and near-infrared adaptive optics images taken by the W.M. Keck telescope on May 11, is revealing the relative altitudes of the cloud tops of the three red ovals. Because all three oval storms are bright in near-infrared light, they must be towering above the methane in Jupiter's atmosphere, which absorbs the Sun's infrared light and so looks dark in infrared images. Turbulence and storms first observed on Jupiter more than two years ago are still raging, as revealed in the latest pictures. The Hubble and Keck images also reveal the change from a rather bland, quiescent band surrounding the Great Red Spot just over a year ago to one of incredible turbulence on both sides of the spot. Red Spot Jr. appeared in spring of 2006. The Great Red Spot has persisted for as long as 200 to 350 years, based on early telescopic observations. If the new red spot and the Great Red Spot continue on their courses, they will encounter each other in August, and the small oval will either be absorbed or repelled from the Great Red Spot. Red Spot Jr. which lies between the two other spots, and is at a lower latitude, will pass the Great Red Spot in June. The Hubble and Keck images may support the idea that Jupiter is in the midst of global climate change, as first proposed in 2004 by Phil Marcus, a professor of mechanical engineering at the University of California, Berkeley. The planet's temperatures may be changing by 15 to 20 degrees Fahrenheit. The giant planet is getting warmer near the equator and cooler near the South Pole. He predicted that large changes would start in the southern hemisphere around 2006, causing the jet streams to become unstable and spawn new vortices. Image and Caption: M. Wong and I. de Pater (University of California, Berkeley) [high-resolution]

Part of the Tarantula Nebula One square degree image of the Tarantula Nebula and its surroundings. The spidery nebula is seen in the upper-centre of the image. Slightly to the lower-right, a web of filaments harbours the famous supernova SN 1987A (see below). Many other reddish nebulae are visible in the image, as well as a cluster of young stars on the left, known as NGC 2100. Technical information: the image is based on observations carried out by Joao Alves (Calar Alto, Spain), Benoit Vandame and Yuri Beletski (ESO) with the Wide Field Imager (WFI) at the 2.2-m telescope on La Silla. These data consist of a 2x2 WFI mosaic in the B- and V-bands, and in the H-alpha and [OIII] narrow bands. The data were first processed with the ESO/MVM pipeline by the Advanced Data Products (ADP) group at ESO. Image: ESO/R. Fosbury (ST-ECF) [high-resolution] Caption: ESO

Nearby Cradle The Milky Way and other galaxies in the universe harbor many young star clusters and associations that each contain hundreds to thousands of hot, massive, young stars known as O and B stars. The star cluster Cygnus OB2 contains more than 60 O-type stars and about a thousand B-type stars. Deep observations with NASA’s Chandra X-ray Observatory have been used to detect the X-ray emission from the hot outer atmospheres, or coronas, of young stars in the cluster and to probe how these fascinating star factories form and evolve. About 1,700 X-ray sources were detected, including about 1,450 thought to be stars in the cluster. In this image, X-rays from Chandra (blue) have been combined with infrared data from NASA’s Spitzer Space Telescope (red) and optical data from the Isaac Newton Telescope (orange). Image: NASA [high-resolution] Caption: NASA

White Dwarf Dance Astronomers using ESO’s Very Large Telescope have discovered a pair of stars orbiting each other at the centre of one of the most remarkable examples of a planetary nebula. The new result confirms a long-debated theory about what controls the spectacular and symmetric appearance of the material flung out into space. The results are published in the 9 November 2012 issue of the journal Science. Planetary nebulae are glowing shells of gas around white dwarfs — Sun-like stars in the final stages of their lives. Fleming 1 is a beautiful example that has strikingly symmetric jets that weave into knotty, curved patterns. It is located in the southern constellation of Centaurus (The Centaur) and was discovered just over a century ago by Williamina Fleming, a former maid who was hired by Harvard College Observatory after showing an aptitude for astronomy. Astronomers have long debated how these symmetric jets could be created, but no consensus has been reached. Now, a research team led by Henri Boffin (ESO, Chile) has combined new Very Large Telescope (VLT) observations of Fleming 1 with existing computer modelling to explain in detail for the first time how these bizarre shapes came about. The team used ESO’s VLT to study the light coming from the central star. They found that Fleming 1 is likely to have not one but two white dwarfs at its centre, circling each other every 1.2 days. Although binary stars have been found at the hearts of planetary nebulae before, systems with two white dwarfs orbiting each other are very rare. “The origin of the beautiful and intricate shapes of Fleming 1 and similar objects has been controversial for many decades,” says Henri Boffin. “Astronomers have suggested a binary star before, but it was always thought that in this case the pair would be well separated, with an orbital period of tens of years or longer. Thanks to our models and observations, which let us examine this unusual system in great detail and peer right into the heart of the nebula, we found the pair to be several thousand times closer.” When a star with a mass up to eight times that of the Sun approaches the end of its life, it blows off its outer shells and begins to lose mass. This allows the hot, inner core of the star to radiate strongly, causing this outward-moving cocoon of gas to glow brightly as a planetary nebula. While stars are spherical, many of these planetary nebulae are strikingly complex, with knots, filaments, and intense jets of material forming intricate patterns. Some of the most spectacular nebulae — including Fleming 1 — present point-symmetric structures. For this planetary nebula it means that the material appears to shoot from both poles of the central region in S-shaped flows. This new study shows that these patterns for Fleming 1 are the result of the close interaction between a pair of stars — the surprising swansong of a stellar couple. “This is the most comprehensive case yet of a binary central star for which simulations have correctly predicted how it shaped the surrounding nebula — and in a truly spectacular fashion,” explains co-author Brent Miszalski, from SAAO and SALT (South Africa). The pair of stars in the middle of this nebula is vital to explain its observed structure. As the stars aged, they expanded, and for part of this time, one acted as a stellar vampire, sucking material from its companion. This material then flowed in towards the vampire, encircling it with a disc known as an accretion disc. As the two stars orbited one another, they both interacted with this disc and caused it to behave like a wobbling spinning top — a type of motion called precession. This movement affects the behaviour of any material that has been pushed outwards from the poles of the system, such as outflowing jets. This study now confirms that precessing accretion discs within binary systems cause the stunningly symmetric patterns around planetary nebulae like Fleming 1. The deep images from the VLT have also led to the discovery of a knotted ring of material within the inner nebula. Such a ring of material is also known to exist in other families of binary systems, and appears to be a telltale signature of the presence of a stellar couple. “Our results bring further confirmation of the role played by interaction between pairs of stars to shape, and perhaps even form, planetary nebulae,” concludes Boffin. Image: ESO/H. Boffin [high-resolution] Caption: ESO

Smiley Crater It looks like even the craters on Mercury have heard of Bob Ross! The central peaks of this complex crater have formed in such a way that it resembles a smiling face. This image is oriented so north is toward the bottom. This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week. Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington [high-resolution] Caption: Mercury Messenger Team

Black Hole Lobes The radio source Cygnus A is produced in a galaxy some 600 million light-years away. The radio waves are coming from electrons propelled at nearly the speed of light through a long, thin "jet" at the core of the galaxy and deposited in giant "radio lobes." It is here where the speeding electrons are trapped by the magnetic field around the galaxy to produce radio waves much like the Van Allen radiation belts around the Earth. Where did all the electrons come from? From the bright, small radio component in the center of the galaxy -- the location of a black hole. Image: Image courtesy of NRAO/AUI. Image courtesy of NRAO/AUI [high-resolution] Caption: NRAO

Gorgeous Aurora Over Oregon "It's not every day you see the aurora in Central Oregon," wrote photographer Brad Goldpaint to Wired regarding his incredible shot of heavenly phenomenon. That is certainly true. Auroras are created when energetic particles flowing from the sun interact with the Earth's upper atmosphere, creating a cascading shower of light with brilliant green, blue, and purple hues. They can typically only be found over the most northern and southern extremes of our planet. Aurora are strongest after a solar energetic particle event, such as a flare, when the sun releases a huge burst of energy and ions. Such an event happened on July 12, 2012, when the sun produced an X-class flare -- the strongest type of flare. Goldpaint knew that this tremendous solar explosion was going to increase the chances of spotting auroras as far south as Central Oregon and he grabbed his camera. On his website's blog, Goldpaint wrote about how he went out to "an area with very little light pollution, a clear view of the night sky facing north, and cross my fingers." Arriving just after sunset, his camera started picking up a faint, pink glow on the horizon. Soon, bursting auroras were coming over the distant mountains. Using long exposures, he was able to capture far more than the human eye can discern. "The magnitude of colors and lights were like I’ve never seen before," he wrote. Goldpaint wrote: "By 2:30am, my efforts and dedication began paying off. The sky exploded!!! A large, thick band of light burst out of nowhere just behind South Sister and slowly drifted all the way to Broken Top and beyond. Immediately after words, the entire sky filled with thin bands of light. I could barely make them out with my own eyes, but my camera picked them up perfectly. The majority of light bands lasted until 3:30am, just as the sun began to rise." "This was by far one of the most unforgettable experiences I’ve ever witnessed and feel this is why I’m so drawn to photography. However, for me, it’s not just about getting the shot, although it was a plus, it’s about escaping my comfort zone and challenging myself to experience something entirely new. I often hear about people who are scared of the dark and would never think about doing what I do. Would you believe me if I said I was afraid of the dark too? Every time I’m out there I get a good scare from a sound I don’t recognize. I believe it’s about conquering one’s fears and allowing your eyes to become your guide." Image: Brad Goldpaint Caption: Brad Goldpaint/Wired Science

Dwarfed by Saturn Saturn's moon Mimas appears near Saturn, dwarfed by its parent planet in this image. Mimas (246 miles, or 396 kilometers across) appears tiny compared to the storms clearly visible in far northern and southern hemispheres of Saturn. This view looks toward the unilluminated side of the rings from about 18 degrees below the ringplane. North on Saturn is up and rotated 27 degrees to the left. The image was taken with the Cassini spacecraft wide-angle camera on Aug. 20, 2012 using a spectral filter sensitive to wavelengths of near-infrared light centered at 752 nanometers. The view was acquired at a distance of approximately 1.5 million miles (2.4 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 64 degrees. Image scale is 87 miles (140 kilometers) per pixel. Photo and Caption: NASA/JPL-Caltech/Space Science Institute. [high-resolution]

Star Formation in LMC This active region of star formation in the Large Magellanic Cloud (LMC), as photographed by NASA's Hubble Space Telescope, unveils wispy clouds of hydrogen and oxygen that swirl and mix with dust on a canvas of astronomical size. The LMC is a satellite galaxy of the Milky Way. This particular region within the LMC, referred to as N 180B, contains some of the brightest known star clusters. The hottest blue stars can be brighter than a million of our Suns. Their intense energy output generates not only harsh ultraviolet radiation but also incredibly strong stellar "winds" of high-speed, charged particles that blow into space. The ultraviolet radiation ionizes the interstellar gas and makes it glow, while the winds can disperse the interstellar gas across tens or hundreds of light-years. Both actions are evident in N 180B. Also visible etched against the glowing hydrogen and oxygen gases are 100 light-year-long dust streamers that run the length of the nebula, intersecting the core of the cluster near the center of the image. Perpendicular to the direction of the dark streamers, bright orange rims of compact dust clouds appear near the bottom right of and top left corners of the image. These dark concentrations are on the order of a few light-years in size. Also visible among the dust clouds are so-called "elephant trunk" stalks of dust. If the pressure from the nearby stellar winds is great enough to compress this material and cause it to gravitationally contract, star formation might be triggered in these small dust clouds. These dust clouds are evidence that this is still a young star-formation region. This image was taken with Hubble's Wide Field Planetary Camera 2 in 1998 using filters that isolate light emitted by hydrogen and oxygen gas. To create a color composite, the data from the hydrogen filter were colorized red, the oxygen filter were colorized blue, and a combination of the two filters averaged together was colorized green. The amalgamation yields pink and orange hydrogen clouds set amid a field of soft blue oxygen gas. Dense dust clouds block starlight and glowing gas from our view point. Image: NASA, ESA, and the Hubble Heritage Team (STScI/AURA) [high-resolution] Caption: Hubble Heritage Team

Chaotic Star Birth Located 1,000 light-years from Earth in the constellation Perseus, a reflection nebula called NGC 1333 epitomizes the beautiful chaos of a dense group of stars being born. Most of the visible light from the young stars in this region is obscured by the dense, dusty cloud in which they formed. With NASA's Spitzer Space Telescope, scientists can detect the infrared light from these objects. This allows a look through the dust to gain a more detailed understanding of how stars like our sun begin their lives. The young stars in NGC 1333 do not form a single cluster, but are split between two sub-groups. One group is to the north near the nebula shown as red in the image. The other group is south, where the features shown in yellow and green abound in the densest part of the natal gas cloud. With the sharp infrared eyes of Spitzer, scientists can detect and characterize the warm and dusty disks of material that surround forming stars. By looking for differences in the disk properties between the two subgroups, they hope to find hints of the star- and planet-formation history of this region. The knotty yellow-green features located in the lower portion of the image are glowing shock fronts where jets of material, spewed from extremely young embryonic stars, are plowing into the cold, dense gas nearby. The sheer number of separate jets that appear in this region is unprecedented. This leads scientists to believe that by stirring up the cold gas, the jets may contribute to the eventual dispersal of the gas cloud, preventing more stars from forming in NGC 1333. In contrast, the upper portion of the image is dominated by the infrared light from warm dust, shown as red. Image: NASA/JPL-Caltech/R. A. Gutermuth (Harvard-Smithsonian CfA) [high-resolution] Caption: Spitzer space telescope

Lightning on Saturn These false-color mosaics from NASA's Cassini spacecraft capture lightning striking within the huge storm that encircled Saturn's northern hemisphere for much of 2011. The larger mosaic on the left of the panel shows the lightning flash, which appears as a blue dot. The smaller mosaic on the right is composed of images taken 30 minutes later, and the lightning is not flashing at that time. The white arrow in the annotated version of this panel points to the location where the lightning occurred in the clouds. The optical energy of this and other flashes on Saturn is comparable to the strongest of the flashes on Earth. The flash is approximately 120 miles (200 kilometers) in diameter when it exits the tops of the clouds. From this, scientists deduce that the lightning bolts originate in the clouds deeper down in Saturn's atmosphere where water droplets freeze. This is analogous to where lightning is created on Earth. This lightning flash appears only in the filter sensitive to blue visible light, and the images were enhanced to increase the visibility of the lightning. Images taken using red, green and blue spectral filters are usually combined to create a natural color view. Because visible red-light images were not available, images taken using a spectral filter sensitive to wavelengths of near-infrared light centered at 752 nanometers were used in place of red. Also, the blue filter image was enhanced to increase the visibility of the lightning. The result is a type of false color image. The images were obtained with the Cassini spacecraft narrow-angle camera on March 6, 2011, at a distance of approximately 2 million miles (3.3 million kilometers) from Saturn and at a sun-Saturn-spacecraft, or phase, angle of 83 degrees. These mosaics are simple cylindrical map projections, defined such that a square pixel subtends equal intervals of latitude and longitude. At higher latitudes, the pixel size in the north-south direction remains the same, but the pixel size (in terms of physical extent on the planet) in the east-west direction becomes smaller. The pixel size is set at the equator, where the distances along the sides are equal. This map has a pixel size of 12 miles (20 kilometers) at the equator. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. Image: NASA/JPL-Caltech/Space Science Institute [high-resolution] Caption: NASA

The Ghost in Cephus Described as a "dusty curtain" or "ghostly apparition," mysterious reflection nebula VdB 152 really is very faint. Far from your neighborhood on this Halloween Night, the cosmic phantom is nearly 1,400 light-years away. Also catalogued as Ced 201, it lies along the northern Milky Way in the royal constellation Cepheus. Near the edge of a large molecular cloud, pockets of interstellar dust in the region block light from background stars or scatter light from the embedded bright star giving parts of the nebula a characteristic blue color. Ultraviolet light from the star is also thought to cause a dim reddish luminescence in the nebular dust. Though stars do form in molecular clouds, this star seems to have only accidentally wandered into the area, as its measured velocity through space is very different from the cloud's velocity. This deep telescopic image of the region spans about 7 light-years. Image: NASA/Stephen Leshin [high-resolution] Caption: NASA

Degas on Mercury Though many craters are visible in this color view of Mercury's limb, Degas gets noticed. Located near the center of the image, the distinctive blue color of the low-reflectance material associated with Degas contrasts with the surrounding terrain and neighboring craters. View these previously posted web images to see Degas in high-resolution with the Narrow Angle Camera (NAC) or in high-resolution color with the WAC. This image was acquired as a targeted observation that occurred simultaneously with a measurement by the Mercury Atmospheric and Surface Composition Spectrometer (MASCS). Targeted observations that involve both MDIS and MASCS facilitate combining the data from both instruments to understand the color and reflectance of small-scale geologic features on Mercury's surface. Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington [high-resolution] Caption: Mercury Messenger Team

Young