 Sunset on MarsOn May 19th, 2005, NASA's Mars Exploration Rover Spirit captured this stunning view as the Sun sank below the rim of Gusev crater on Mars. This Panoramic Camera (Pancam) mosaic was taken around 6:07 in the evening of the rover's 489th martian day, or sol. Spirit was commanded to stay awake briefly after sending that sol's data to the Mars Odyssey orbiter just before sunset. This small panorama of the western sky was obtained using Pancam's 750-nanometer, 530-nanometer and 430-nanometer color filters. This filter combination allows false color images to be generated that are similar to what a human would see, but with the colors slightly exaggerated. In this image, the bluish glow in the sky above the Sun would be visible to us if we were there, but an artifact of the Pancam's infrared imaging capabilities is that with this filter combination the redness of the sky farther from the sunset is exaggerated compared to the daytime colors of the martian sky. Because Mars is farther from the Sun than the Earth is, the Sun appears only about two-thirds the size that it appears in a sunset seen from the Earth. The terrain in the foreground is the rock outcrop "Jibsheet", a feature that Spirit has been investigating for several weeks (rover tracks are dimly visible leading up to Jibsheet). The floor of Gusev crater is visible in the distance, and the Sun is setting behind the wall of Gusev some 80 km (50 miles) in the distance. This mosaic is yet another example from MER of a beautiful, sublime martian scene that also captures some important scientific information. Specifically, sunset and twilight images are occasionally acquired by the science team to determine how high into the atmosphere the martian dust extends, and to look for dust or ice clouds. Other images have shown that the twilight glow remains visible, but increasingly fainter, for up to two hours before sunrise or after sunset. The long martian twilight (compared to Earth's) is caused by sunlight scattered around to the night side of the planet by abundant high altitude dust. Similar long twilights or extra-colorful sunrises and sunsets sometimes occur on Earth when tiny dust grains that are erupted from powerful volcanoes scatter light high in the atmosphere. Image: NASA/JPL/Texas A&M/Cornell [high-resolution] Caption: NASA/JPL/Texas A&M/Cornell  Dark Cloud Around Young StarsThis evocative image shows a dark cloud where new stars are forming along with a cluster of brilliant stars that have already emerged from their dusty stellar nursery. This cloud is known as Lupus 3 and it lies about 600 light-years from Earth in the constellation of Scorpius (The Scorpion). It is likely that the Sun formed in a similar star formation region more than four billion years ago. This picture was taken with the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile and is the best image ever taken of this little-known object. Image: ESO/F. Comeron [high-resolution] Caption: ESO  Moody, Glowing Saturn AurorasThis false-color composite image, constructed from data obtained by NASA's Cassini spacecraft, shows the glow of auroras streaking out about 1,000 km (600 miles) from the cloud tops of Saturn's south polar region. It is among the first images released from a study that identifies images showing auroral emissions out of the entire catalogue of images taken by Cassini's visual and infrared mapping spectrometer. In this image constructed from data collected in the near-infrared wavelengths of light, the auroral emission is shown in green. The data represents emissions from hydrogen ions in of light between 3 and 4 microns in wavelength. In general, scientists designated blue to indicate sunlight reflected at a wavelength of 2 microns, green to indicate sunlight reflected at 3 microns and red to indicate thermal emission at 5 microns. Saturn's rings reflect sunlight at 2 microns, but not at 3 and 5 microns, so they appear deep blue. Saturn's high altitude haze reflects sunlight at both 2 and 3 microns, but not at 5 microns, and so it appears green to blue-green. The heat emission from the interior of Saturn is only seen at 5 microns wavelength in the spectrometer data, and thus appears red. The dark spots and banded features in the image are clouds and small storms that outline the deeper weather systems and circulation patterns of the planet. They are illuminated from underneath by Saturn's thermal emission, and thus appear in silhouette. The composite image was made from 65 individual observations by Cassini's visual and infrared mapping spectrometer on 1 November 2008. The observations were each six minutes long. Image: NASA/JPL/University of Arizona/University of Leicester [high-resolution] Caption: Cassini Solstice team  Supermassive Star Eta CarinaeA huge, billowing pair of gas and dust clouds are captured in this stunning NASA Hubble Space Telescope image of the supermassive star Eta Carinae. Using a combination of image processing techniques (dithering, subsampling and deconvolution), astronomers created one of the highest resolution images of an extended object ever produced by the Hubble Space Telescope. The resulting picture reveals astonishing detail. Even though Eta Carinae is more than 8,000 light-years away, structures only 10 billion miles across (about the diameter of our solar system) can be distinguished. Dust lanes, tiny condensations, and strange radial streaks all appear with unprecedented clarity. Eta Carinae was observed by Hubble in September 1995 with the Wide Field Planetary Camera 2 (WFPC2). Images taken through red and near-ultraviolet filters were subsequently combined to produce the color image shown. A sequence of eight exposures was necessary to cover the object's huge dynamic range: the outer ejecta blobs are 100,000 times fainter than the brilliant central star. Eta Carinae was the site of a giant outburst about 150 years ago, when it became one of the brightest stars in the southern sky. Though the star released as much visible light as a supernova explosion, it survived the outburst. Somehow, the explosion produced two polar lobes and a large thin equatorial disk, all moving outward at about 1.5 million miles per hour. The new observation shows that excess violet light escapes along the equatorial plane between the bipolar lobes. Apparently there is relatively little dusty debris between the lobes down by the star; most of the blue light is able to escape. The lobes, on the other hand, contain large amounts of dust which preferentially absorb blue light, causing the lobes to appear reddish. Estimated to be 100 times more massive than our Sun, Eta Carinae may be one of the most massive stars in our Galaxy. It radiates about five million times more power than our Sun. The star remains one of the great mysteries of stellar astronomy, and the new Hubble images raise further puzzles. Eventually, this star's outburst may provide unique clues to other, more modest stellar bipolar explosions and to hydrodynamic flows from stars in general. Image: Nathan Smith (University of California, Berkeley), and NASA [high-resolution] Caption: Hubble Heritage team  Rings of Raditladi CraterThis image, taken with the Wide Angle Camera (WAC), shows the outer rim and inner peak ring of Raditladi basin. The basin's smooth floor and well-preserved peak ring structure indicate that Raditladi is relatively young. The concentric troughs along the floor near the basin's center formed by extension (pulling apart) of the surface and are similar to those seen in Caloris basin and Rembrandt basin. The bright areas around the peak ring are an excellent example of hollows, shallow depressions that may have been formed by the loss of volatile materials. This image was acquired as part of MDIS's high-resolution stereo imaging campaign. Images from the stereo imaging campaign are used in combination with the surface morphology base map or the albedo base map to create high-resolution stereo views of Mercury's surface, with an average resolution of 200 meters/pixel. Viewing the surface under the same Sun illumination conditions but from two or more viewing angles enables information about the small-scale topography of Mercury's surface to be obtained. Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington [high-resolution] Caption: Mercury Messenger Team  Crashing Mice GalaxiesThe Advanced Camera for Surveys (ACS), the newest camera on NASA's Hubble Space Telescope, has captured a spectacular pair of galaxies engaged in a celestial dance of cat and mouse or, in this case, mouse and mouse. Located 300 million light-years away in the constellation Coma Berenices, the colliding galaxies have been nicknamed "The Mice" because of the long tails of stars and gas emanating from each galaxy. Otherwise known as NGC 4676, the pair will eventually merge into a single giant galaxy. The image shows the most detail and the most stars that have ever been seen in these galaxies. In the galaxy at left, the bright blue patch is resolved into a vigorous cascade of clusters and associations of young, hot blue stars, whose formation has been triggered by the tidal forces of the gravitational interaction. Streams of material can also be seen flowing between the two galaxies. The clumps of young stars in the long, straight tidal tail [upper right] are separated by fainter regions of material. These dim regions suggest that the clumps of stars have formed from the gravitational collapse of the gas and dust that once occupied those areas. Some of the clumps have luminous masses comparable to dwarf galaxies that orbit in the halo of our own Milky Way Galaxy. Computer simulations by astronomers Josh Barnes (University of Hawaii) and John Hibbard (National Radio Astronomy Observatory, Charlottesville, Va.) show that we are seeing two nearly identical spiral galaxies approximately 160 million years after their closest encounter. The long, straight arm is actually curved, but appears straight because we see it edge-on. The simulations also show that the pair will eventually merge, forming a large, nearly spherical galaxy (known as an elliptical galaxy). The stars, gas, and luminous clumps of stars in the tidal tails will either fall back into the merged galaxies or orbit in the halo of the newly formed elliptical galaxy. The Mice presage what may happen to our own Milky Way several billion years from now when it collides with our nearest large neighbor, the Andromeda Galaxy (M31). This picture is assembled from three sets of images taken on April 7, 2002, in blue, orange, and near-infrared filters. Image: NASA, H. Ford (JHU), G. Illingworth (UCSC/LO), M.Clampin (STScI), G. Hartig (STScI), the ACS Science Team, and ESA [high-resolution] Caption: Hubble Heritage Team  Cracks in Landon BasinESA’s Mars Express has observed the southern part of a partially buried approx. 440-km wide crater, informally named Ladon basin. The images, near to where Ladon Valles enters this large impact region reveal a variety of features, most notably the double interconnected impact craters Sigli and Shambe, the basins of which are criss-crossed by extensive fracturing. This region, imaged on 27 April by the high-resolution stereo camera on Mars Express is of great interest to scientists since it shows significant signs of ancient lakes and rivers. Both Holden and Eberswalde Craters were on the final shortlist of four candidate landing sites for NASA’s Mars Science Laboratory, which is due now to land in Gale Crater on 6 August. Large-scale overview maps show clear evidence that vast volumes of water once flowed from the southern highlands. This water carved Ladon Valles, eventually flowing into Ladon basin, an ancient large impact region. Elliptical craters like this 16 km-wide example are formed when asteroids or comets strike the surface of the planet at a shallow angle. Scientists have suggested that a fluidised ejecta pattern indicates the presence of subsurface ice which melted during the impact. Subsequent impacts have created a number of smaller craters in the ejecta blanket. Image: ESA/DLR/FU Berlin (G. Neukum) [high-resolution] Caption: Mars Express Team  The Star FactoryThis is a near-infrared, colour-coded composite image of a sky field in the south-western part of the galactic star-forming region Messier 17. In this image, young and heavily obscured stars are recognized by their red colour. Bluer objects are either foreground stars or well-developed massive stars whose intense light ionizes the hydrogen in this region. The diffuse light that is visible nearly everywhere in the photo is due to emission from hydrogen atoms that have (re-)combined from protons and electrons. The dark areas are due to obscuration of the light from background objects by large amounts of dust — this effect also causes many of those stars to appear quite red. A cluster of young stars in the upper-left part of the photo, so deeply embedded in the nebula that it is invisible in optical light, is well visible in this infrared image. Technical information : The exposures were made through three filtres, J (at wavelength 1.25 μm; exposure time 5 min; here rendered as blue), H (1.65 μm; 5 min; green) and Ks (2.2 μm; 5 min; red); an additional 15 min was spent on separate sky frames. The seeing was 0.5 - 0.6 arcsec. The objects in the uppermost left corner area appear somewhat elongated because of a colour-dependent aberration introduced at the edge by the large-field optics. The sky field shown measures approx. 5 x 5 arcmin 2 (corresponding to about 3% of the full moon). North is up and East is left. Image: ESO [high-resolution] Caption: ESO  Enceladus Jets at SunsetAs the long winter night deepens at Enceladus' south pole, its jets are also progressively falling into darkness. The shadow of the moon itself is slowly creeping up the jets making the portions closest to the surface difficult to observe by the Cassini spacecraft. Cassini looks toward the night side of Enceladus (313 miles, or 504 kilometers across) in this image. Enceladus is lit by light reflected off Saturn rather than by direct sunlight. This view looks toward the Saturn-facing hemisphere of Enceladus. North on Enceladus is up. The image was taken with the Cassini spacecraft narrow-angle camera on Sept. 24, 2012 using a spectral filter sensitive to wavelengths of near-infrared light centered at 930 nanometers. The view was acquired at a distance of approximately 452,000 miles (728,000 kilometers) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 170 degrees. Scale in the original image was 3 miles (4 kilometers) per pixel. The image was magnified by a factor of three to enhance the visibility of jets. Image: NASA/JPL-Caltech/Space Science Institute [high-resolution] Caption: Cassini Solstice Team  Globular Stellar ClusterThis bright cluster of stars is 47 Tucanae (NGC 104), shown here in an image taken by ESO’s VISTA (Visible and Infrared Survey Telescope for Astronomy) from the Paranal Observatory in Chile. This cluster is located around 15 000 light-years away from us and contains millions of stars, some of which are unusual and exotic. This image was taken as part of the VISTA Magellanic Cloud survey, a project that is scanning the region of the Magellanic Clouds, two small galaxies that are very close to our Milky Way. Image: SO/M.-R. Cioni/VISTA Magellanic Cloud survey. Acknowledgment: Cambridge Astronomical Survey Unit[ high-resolution] Caption: ESO  Looking Down at JupiterThese color maps of Jupiter were constructed from images taken by the narrow-angle camera onboard NASA's Cassini spacecraft on Dec. 11 and 12, 2000, as the spacecraft neared Jupiter during its flyby of the giant planet. Cassini was on its way to Saturn. They are the most detailed global color maps of Jupiter ever produced. The smallest visible features are about 120 kilometers (75 miles) across. The maps are composed of 36 images: a pair of images covering Jupiter's northern and southern hemispheres was acquired in two colors every hour for nine hours as Jupiter rotated beneath the spacecraft. Although the raw images are in just two colors, 750 nanometers (near-infrared) and 451 nanometers (blue), the map's colors are close to those the human eye would see when gazing at Jupiter. The maps show a variety of colorful cloud features, including parallel reddish-brown and white bands, the Great Red Spot, multi-lobed chaotic regions, white ovals and many small vortices. Many clouds appear in streaks and waves due to continual stretching and folding by Jupiter's winds and turbulence. The bluish-gray features along the north edge of the central bright band are equatorial "hot spots," meteorological systems such as the one entered by NASA's Galileo probe. Small bright spots within the orange band north of the equator are lightning-bearing thunderstorms. The polar regions are less clearly visible because Cassini viewed them at an angle and through thicker atmospheric haze (such as the whitish material in the south polar map) Pixels in the rectangular map cover equal increments of planetocentric latitude (which is measured relative to the center of the planet) and longitude, and extend to 180 degrees of latitude and 360 degrees of longitude. 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/Space Science Institute [high-resolution] Caption: NASA Black Holes Blazing in X-RaysThis new view of spiral galaxy IC 342, also known as Caldwell 5, includes data from NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR. High-energy X-ray data from NuSTAR have been translated to the color magenta, and superimposed on a visible-light view highlighting the galaxy and its star-studded arms. NuSTAR is the first orbiting telescope to take focused pictures of the cosmos in high-energy X-ray light; previous observations of this same galaxy taken at similar wavelengths blurred the entire object into one pixel. The two magenta spots are blazing black holes first detected at lower-energy X-ray wavelengths by NASA's Chandra X-ray Observatory. With NuSTAR's complementary data, astronomers can start to home in on the black holes' mysterious properties. The black holes appear much brighter than typical stellar-mass black holes, such as those that pepper our own galaxy, yet they cannot be supermassive black holes or they would have sunk to the galaxy’s center. Instead, they may be intermediate in mass, or there may be something else going on to explain their extremely energetic state. NuSTAR will help solve this puzzle. IC 342 lies 7 million light-years away in the Camelopardalis constellation. The outer edges of the galaxy cannot be seen in this view. This image shows NuSTAR X-ray data taken at 10 to 35 kiloelectron volts. The visible-light image is from the Digitized Sky Survey. Image: NASA/JPL-Caltech/DSS [high-resolution] Caption: NASA Polar Ring GalaxyThe stunning ring galaxy NGC 660 is the shimmering aftermath of a galactic collision, located 44 million light-years away in the constellation Pisces. On January 7,astronomers announced that the galaxy was producing massive outbursts, powerful belches that are likely the product of a gorging supermassive black hole at the galaxy's center. Using a network of telescopes including the 305-meter dish in Arecibo, Puerto Rico, the team spotted five sites of bright radio emissions, one near the center of the galaxy and two on either side. Suspected to be jets coming from the galactic core, the emissions are brighter than supernovas when observed at radio wavelengths. The team plans to continue observing NGC 660 to determine if the jet hypothesis is correct. Image: Gemini Observatory/AURA; Color composite produced by Travis Rector, University of Alaska Anchorage. [high-resolution] Caption: NRAO Beautiful Bug NebulaThe Bug Nebula, NGC 6302, is one of the brightest and most extreme planetary nebulae known. It is located about 4,000 light-years away, towards the Scorpius constellation (the Scorpion). The nebula is the swansong of a dying solar-like star lying at its centre. At about 250,000 degrees Celsius and smothered in a blanket of hailstones, the star itself has never been observed as it is surrounded by a dense disc of gas and dust, opaque to light. This dense disc may be the origin of the hourglass structure of the nebula. This colour image, which nicely highlights the complex structure of the nebula, is a composite of three exposures through blue, green and red filters. It was made using the 1.5-metre Danish telescope at the ESO La Silla Observatory, Chile. Image: ESO/IDA/Danish 1.5 m/R. Gendler, A. Hornstrup and J.-E. Ovaldsen [high-resolution] Caption: ESO Colorful Lunar MareGalileo false-color image of the Mare Tranquillitatis and Mare Serenitatis areas of the Moon. The picture was made from four exposures taken during Galileo's second Earth/Moon flyby. The colors are enhanced to highlight compositional differences. Mare Tranquillitatis at left appears blue due to titanium enrichment. Orange soil in Mare Sarenitatis at lower right indicates lower titanium. Dark purple areas at left center mark the Apollo 17 landing site, composed of explosive volcanic deposits. Red lunar highlands indicate low iron and titanium. Mare Serenitatis is roughly 1300 km across and North is at 5:00. The 95 km diameter crater Posidonius, centered at 32 N, 30 E, is at the middle of the bottom of the frame. Image: NASA [high-resolution] Caption: NASA Prominent Solar FlareA solar eruption gracefully rose up from the sun on Dec. 31, 2012, twisting and turning. Magnetic forces drove the flow of plasma, but without sufficient force to overcome the sun’s gravity much of the plasma fell back into the sun. The length of the eruption extends about 160,000 miles out from the Sun. With Earth about 7,900 miles in diameter, this relatively minor eruption is about 20 times the diameter of our planet. See video and relative size of Earth to eruption on 'Solar Ballet on the Sun' feature. Image: NASA/SDO [high-resolution] Caption: NASA Vesta Crater in 3DThis composite-color view from NASA's Dawn mission shows Cornelia Crater, streaked with dark materials, on the giant asteroid Vesta. The data were obtained by Dawn's framing camera during the mission's high-altitude mapping orbit, about 420 miles (680 kilometers) above the surface. The images were integrated into a mosaic and wrapped on a topographical model of Vesta's surface. Scientists colorized the picture by assigning red to the 0.75-micron wavelength, green to the 0.92-micron wavelength and blue to the 0.98-micron wavelength. The Dawn mission to Vesta and Ceres is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate, Washington. UCLA is responsible for overall Dawn mission science. The Dawn framing cameras were developed and built under the leadership of the Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, with significant contributions by DLR German Aerospace Center, Institute of Planetary Research, Berlin, and in coordination with the Institute of Computer and Communication Network Engineering, Braunschweig. The framing camera project is funded by the Max Planck Society, DLR, and NASA/JPL. Image: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA [high-resolution] Caption: NASA Galactic Bar and RingThe NASA/ESA Hubble Space Telescope provides us this week with a spectacular image of the bright star-forming ring that surrounds the heart of the barred spiral galaxy NGC 1097. In this image, the larger-scale structure of the galaxy is barely visible: its comparatively dim spiral arms, which surround its heart in a loose embrace, reach out beyond the edges of this frame. This face-on galaxy, lying 45 million light-years away from Earth in the southern constellation of Fornax (The Furnace), is particularly attractive for astronomers. NGC 1097 is a Seyfert galaxy. Lurking at the very centre of the galaxy, a supermassive black hole 100 million times the mass of our Sun is gradually sucking in the matter around it. The area immediately around the black hole shines powerfully with radiation coming from the material falling in. The distinctive ring around the black hole is bursting with new star formation due to an inflow of material toward the central bar of the galaxy. These star-forming regions are glowing brightly thanks to emission from clouds of ionised hydrogen. The ring is around 5000 light-years across, although the spiral arms of the galaxy extend tens of thousands of light-years beyond it. NGC 1097 is also pretty exciting for supernova hunters. The galaxy experienced three supernovae (the violent deaths of high-mass stars) in the 11-year span between 1992 and 2003. This is definitely a galaxy worth checking on a regular basis. However, what it is really exciting about NGC 1097 is that it is not wandering alone through space. It has two small galaxy companions, which dance “the dance of stars and the dance of space” like the gracious dancer of the famous poem The Dancer by Khalil Gibran. The satellite galaxies are NGC 1097A, an elliptical galaxy orbiting 42 000 light-years from the centre of NGC 1097 and a small dwarf galaxy named NGC 1097B. Both galaxies are located out beyond the frames of this image and they cannot be seen. Astronomers have indications that NGC 1097 and NGC 1097A have interacted in the past. This picture was taken with Hubble’s Advanced Camera for Surveys using visual and infrared filters. A version of this image was submitted to the Hubble’s Hidden Treasures image processing competition by contestant Eedresha Sturdivant. Image: NASA/ESA/Hubble [high-resolution] Caption: Hubble Heritage Team Star Formation in Milky WayThis image displays a spectacular three-colour composite image of RCW38, obtained through three near-infrared filters. This is a region in the Milky Way at a distance of about 5,000 light years, where stars which have recently formed in clouds of gas and dust are still heavily obscured and cannot be observed in the visible part of the spectrum. Contrarily, as this image shows, they are very well seen at infrared wavelengths where the obscuration is substantially lower. The diffuse radiation is a mixture of starlight scattered by the dust and gas in the area, and atomic and molecular hydrogen line emission. Image: ESO [high-resolution] Caption: ESO |
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