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Astronomy Picture of the Day (General/Chat)

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  • Astronomy Picture of the Day -- Comet McNaught Over New Zealand

    10/19/2014 5:20:31 PM PDT · by SunkenCiv · 4 replies
    NASA ^ | October 19, 2014 | (see photo credit)
    Explanation: Comet McNaught was perhaps the most photogenic comet of modern times -- from Earth. After making quite a show in the northern hemisphere in early January of 2007, the comet moved south and developed a long and unusual dust tail that dazzled southern hemisphere observers. In late January 2007, Comet McNaught was captured between Mount Remarkable and Cecil Peak in this spectacular image taken from Queenstown, South Island, New Zealand. The bright comet dominates the right part of the above image, while the central band of our Milky Way Galaxy dominates the left. Careful inspection of the image will...
  • Astronomy Picture of the Day -- Melotte 15 in the Heart

    10/19/2014 5:19:04 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | October 18, 2014 | (see photo credit)
    Explanation: Cosmic clouds form fantastic shapes in the central regions of emission nebula IC 1805. The clouds are sculpted by stellar winds and radiation from massive hot stars in the nebula's newborn star cluster, Melotte 15. About 1.5 million years young, the cluster stars are toward the right in this colorful skyscape, along with dark dust clouds in silhouette against glowing atomic gas. A composite of narrowband and broadband telescopic images, the view spans about 30 light-years and includes emission from ionized hydrogen, sulfur, and oxygen atoms mapped to green, red, and blue hues in the popular Hubble Palette. Wider...
  • Astronomy Picture of the Day -- Messier 6 and Comet Siding Spring

    10/17/2014 5:07:23 AM PDT · by SunkenCiv · 7 replies
    NASA ^ | October 17, 2014 | (see photo credit)
    Explanation: This looks like a near miss but the greenish coma and tail of Comet Siding Spring (C/2013 A1) are really 2,000 light-years or so away from the stars of open cluster Messier 6. They do appear close together though, along the same line-of-sight in this gorgeous October 9th skyscape toward the constellation Scorpius. Still, on Sunday, October 19th this comet really will be involved in a near miss, passing within only 139,500 kilometers of planet Mars. That's about 10 times closer than any known comet flyby of planet Earth, and nearly one third the Earth-Moon distance. While an impact...
  • Astronomy Picture of the Day -- Rosetta's Selfie

    10/16/2014 5:33:20 PM PDT · by SunkenCiv · 14 replies
    NASA ^ | October 16, 2014 | (see photo credit)
    Explanation: This Rosetta spacecraft selfie was snapped on October 7th. At the time the spacecraft was about 472 million kilometers from planet Earth, but only 16 kilometers from the surface of comet 67P/Churyumov-Gerasimenko. Looming beyond the spacecraft near the top of the frame, dust and gas stream away from the comet's curious double-lobed nucleus and bright sunlight glints off one of Rosetta's 14 meter long solar arrays. In fact, two exposures, one short and one long, were combined to record the dramatic high contrast scene using the CIVA camera system on Rosetta's still-attached Philae lander. Its chosen primary landing site...
  • Astronomy Picture of the Day -- Mysterious Changing feature on Titan

    10/15/2014 5:50:53 PM PDT · by SunkenCiv · 12 replies
    NASA ^ | October 15, 2014 | (see photo credit)
    Explanation: What is that changing object in a cold hydrocarbon sea of Titan? Radar images from the robotic Cassini spacecraft orbiting Saturn have been recording the surface of the cloud-engulfed moon Titan for years. When imaging the flat -- and hence radar dark -- surface of the methane and ethane lake called Ligeia Mare, an object appeared in 2013 just was not there in 2007. Subsequent observations in 2014 found the object remained -- but had changed! The featured image shows how the 20-km long object has appeared and evolved. Current origin speculative explanations include bubbling foam and floating solids,...
  • Astronomy Picture of the Day -- Auroral Corona over Norway

    10/15/2014 5:48:49 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | October 14, 2014 | (see photo credit)
    Explanation: Higher than the highest mountain lies the realm of the aurora. Auroras rarely reach below 60 kilometers, and can range up to 1000 kilometers. Aurora light results from energetic electrons and protons striking atoms and molecules in the Earth's atmosphere. Somewhat uncommon, an auroral corona appears as a center point for a surrounding display and may occur when an aurora develops directly overhead, or when auroral rays are pointed nearly toward the observer. This picturesque but brief green and purple aurora exhibition occurred last month high above Kvaløya, Tromsø, Norway. The Sessøyfjorden fjord runs through the foreground, while numerous...
  • Astronomy Picture of the Day -- Sprite Lightning in Slow Motion

    10/15/2014 5:47:28 PM PDT · by SunkenCiv · 9 replies
    NASA ^ | October 13, 2014 | (see photo credit)
    Explanation: What causes sprite lightning? Mysterious bursts of light in the sky that momentarily resemble gigantic jellyfish have been recorded for over 25 years, but their root cause remains unknown. Some thunderstorms have them -- most don't. Recently, however, high speed videos are better detailing how sprites actually develop. The featured video is fast enough -- at about 10,000 frames per second -- to time-resolve several sprite "bombs" dropping and developing into the multi-pronged streamers that appear on still images. Unfortunately, the visual clues provided by these videos do not fully resolve the sprite origins mystery. They do indicate to...
  • Astronomy Picture of the Day -- The Helix Nebula from Blanco and Hubble

    10/11/2014 9:28:32 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | October 12, 2014 | (see photo credit)
    Explanation: How did a star create the Helix nebula? The shapes of planetary nebula like the Helix are important because they likely hold clues to how stars like the Sun end their lives. Observations by the orbiting Hubble Space Telescope and the 4-meter Blanco Telescope in Chile, however, have shown the Helix is not really a simple helix. Rather, it incorporates two nearly perpendicular disks as well as arcs, shocks, and even features not well understood. Even so, many strikingly geometric symmetries remain. How a single Sun-like star created such beautiful yet geometric complexity is a topic of research. The...
  • Astronomy Picture of the Day -- Eclipse at Moonrise

    10/11/2014 8:51:18 AM PDT · by SunkenCiv · 1 replies
    NASA ^ | October 11, 2014 | (see photo credit)
    Explanation: As the Moon rose and the Sun set on October 8, a lunar eclipse was in progress seen from Chongqing, China. Trailing through this composite time exposure, the rising Moon began as a dark reddened disk in total eclipse near the eastern horizon. Steadily climbing above the populous city's colorful lights along the Yangtze River, the moontrail grows brighter and broader, until a bright Full Moon emerged from the Earth's shadow in evening skies. Although lunar eclipses are not always total ones, this eclipse, along with last April's lunar eclipse, were the first two of four consecutive total lunar...
  • Astronomy Picture of the Day -- Moons at Opposition

    10/11/2014 8:15:00 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | October 10, 2014 | (see photo credit)
    Explanation: From the early hours of October 8, over the Santa Cruz Mountains near Los Gatos, California, the totally eclipsed Moon shows a range of color across this well-exposed telescopic view of the lunar eclipse. Of course, a lunar eclipse can only occur when the Moon is opposite the Sun in Earth's sky and gliding through the planet's shadow. But also near opposition during this eclipse, and remarkably only half a degree or so from the lunar limb, distant Uranus is faint but easy to spot at the lower right. Fainter still are the ice giant's moons. To find them,...
  • Astronomy Picture of the Day -- Eclipse at Moonset

    10/11/2014 8:12:35 AM PDT · by SunkenCiv · 8 replies
    NASA ^ | October 09, 2014 | (see photo credit)
    Explanation: The Pacific Ocean and Chilean coast lie below this sea of clouds. Seen through the subtle colors of the predawn sky a lunar eclipse is in progress above, the partially eclipsed Moon growing dark. The curved edge of planet Earth's shadow still cuts across the middle of the lunar disk as the Moon sinks lower toward the western horizon. In fact, from this southern hemisphere location as well as much of eastern North America totality, the Moon completely immersed within Earth's shadow, began near the time of moonset and sunrise on October 8. From farther west the total phase...
  • Astronomy Picture of the Day -- NGC 6823: Cloud Sculpting Star Cluster

    10/08/2014 9:10:16 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | October 08, 2014 | (see photo credit)
    Explanation: Star cluster NGC 6823 is slowly turning gas clouds into stars. The center of the open cluster, visible on the upper right, formed only about two million years ago and is dominated in brightness by a host of bright young blue stars. Some outer parts of the cluster, visible in the featured image's center as the stars and pillars of emission nebula NGC 6820, contain even younger stars. The huge pillars of gas and dust likely get their elongated shape by erosion from hot radiation emitted from the brightest cluster stars. Striking dark globules of gas and dust are...
  • Astronomy Picture of the Day -- From the Temple of the Sun to the Temple of the Moon

    10/07/2014 3:53:23 AM PDT · by SunkenCiv · 6 replies
    NASA ^ | October 07, 2014 | (see photo credit)
    Explanation: What connects the Sun to the Moon? Many answers have been given throughout history, but in the case of today's featured image, it appears to be the plane of our Milky Way Galaxy. The 16-image panorama was taken in Capitol Reef National Park, Utah, USA where two sandstone monoliths -- the Temple of the Moon on the left and the Temple of the Sun on the right -- rise dramatically from the desert. Each natural monument stands about 100 meters tall and survives from the Jurassic period 160 million years ago. Even older are many of the stars and...
  • Astronomy Picture of the Day -- Space Station Detector Finds Unexplained Positron Excess

    10/07/2014 3:49:51 AM PDT · by SunkenCiv · 6 replies
    NASA ^ | October 06, 2014 | (see photo credit)
    Explanation: Where did all these high energy positrons come from? The Alpha Magnetic Spectrometer (AMS-02) onboard the International Space Station (ISS) has been meticulously recording how often it is struck by both high energy electrons and positrons since 2011. After accumulating years of data, it has now become clear that there are significantly more positrons than expected at the highest energies detected. The excess may have a very exciting and profound origin -- the annihilation of distant but previously undetected dark matter particles. However, it is also possible that astronomical sources such as pulsars are creating the unexplained discrepancy. The...
  • Astronomy Picture of the Day -- A Total Lunar Eclipse Over Tajikistan

    10/04/2014 10:05:05 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | October 05, 2014 | (see photo credit)
    Explanation: If the full Moon suddenly faded, what would you see? The answer during the total lunar eclipse of 2011 June was recorded in a dramatic time lapse video from Tajikistan. During a total lunar eclipse, the Earth moves between the Moon and the Sun, causing the moon to fade dramatically. The Moon never gets completely dark, though, since the Earth's atmosphere refracts some light. As the above video begins, the scene may appear to be daytime and sunlit, but actually it is a nighttime and lit by the glow of the full Moon. As the moon becomes eclipsed and...
  • Astronomy Picture of the Day -- Mars, Antares, Moon and Saturn

    10/04/2014 3:40:58 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | October 04, 2014 | (see photo credit)
    Explanation: Mars, Antares, Moon, and Saturn are the brightest celestial beacons in this serene sky. The Sun's golden light is still scattered along the southwestern horizon though, captured after sunset on September 28. The evening gathering of wandering planets and Moon along with the bright star viewed as an equal to Mars and the Scorpion's Heart was enjoyed around planet Earth. But from the photographer's perspective looking across the calm waters of Lake Balaton, Hungary, they were joined by a more terrestrial sailboat mast light. Mast light, bright star, planets and Moon are all posing near the plane of the...
  • Astronomy Picture of the Day -- Aurora and Milky Way in a Little Sky

    10/04/2014 3:39:00 PM PDT · by SunkenCiv · 1 replies
    NASA ^ | October 03, 2014 | (see photo credit)
    Explanation: Stepping stones seem to lead to the Milky Way as it stretches across this little sky. Of course, the scene is really the northern hemisphere's autumnal equinox night. Water and sky are inverted by a top to bottom, around the horizon stereographic projection centered on the zenith above Lake Storsjön in Jämtland, Sweden. In the north the Milky Way arcs from east to west overhead as fall begins, but the season is also a good time for viewing aurora. Geomagnetic storms increase in frequency near the equinox and produce remarkable displays of northern lights at high latitudes, like the...
  • Astronomy Picture of the Day -- The Bubble Nebula

    10/04/2014 3:36:02 PM PDT · by SunkenCiv · 16 replies
    NASA ^ | October 02, 2014 | (see photo credit)
    Explanation: Blown by the wind from a massive star, this interstellar apparition has a surprisingly familiar shape. Cataloged as NGC 7635, it is also known simply as The Bubble Nebula. Although it looks delicate, the 10 light-year diameter bubble offers evidence of violent processes at work. Below and left of the Bubble's center is a hot, O star, several hundred thousand times more luminous and around 45 times more massive than the Sun. A fierce stellar wind and intense radiation from that star has blasted out the structure of glowing gas against denser material in a surrounding molecular cloud. The...
  • Astronomy Picture of the Day -- The Butterfly Nebula from Hubble

    10/04/2014 3:33:19 PM PDT · by SunkenCiv · 4 replies
    NASA ^ | October 01, 2014 | (see photo credit)
    Explanation: The bright clusters and nebulae of planet Earth's night sky are often named for flowers or insects. Though its wingspan covers over 3 light-years, NGC 6302 is no exception. With an estimated surface temperature of about 250,000 degrees C, the dying central star of this particular planetary nebula has become exceptionally hot, shining brightly in ultraviolet light but hidden from direct view by a dense torus of dust. This sharp close-up of the dying star's nebula was recorded in 2009 by the Hubble Space Telescope's Wide Field Camera 3, and is presented here in reprocessed colors. Cutting across a...
  • Astronomy Picture of the Day -- A Full Circle Rainbow over Australia

    10/04/2014 3:29:34 PM PDT · by SunkenCiv · 9 replies
    NASA ^ | September 30, 2014 | (see photo credit)
    Explanation: Have you ever seen an entire rainbow? From the ground, typically, only the top portion of a rainbow is visible because directions toward the ground have fewer raindrops. From the air, though, the entire 360 degree circle of a rainbow is more commonly visible. Pictured here, a full circle rainbow was captured over Cottesloe Beach near Perth, Australia last year by a helicopter flying between a setting sun and a downpour. An observer-dependent phenomenon primarily caused by the internal reflection of sunlight by raindrops, the 84-degree diameter rainbow followed the helicopter, intact, for about 5 kilometers. As a bonus,...
  • Astronomy Picture of the Day -- Unusual Rocks near Pahrump Hills on Mars

    10/04/2014 3:25:45 PM PDT · by SunkenCiv · 24 replies
    NASA ^ | September 29, 2014 | (see photo credit)
    Explanation: How did these Martian rocks form? As the robotic Curiosity rover has approached Pahrump Hills on Mars, it has seen an interesting and textured landscape dotted by some unusual rocks. The featured image shows a curiously round rock spanning about two centimeters across. Seemingly a larger version of numerous spherules dubbed blueberries found by the Opportunity rover on Mars in 2004, what caused this roundness remains unknown. Possibilities include frequent tumbling in flowing water, sprayed molten rock in a volcanic eruption, or a concretion mechanism. The inset image, taken a few days later, shows another small but unusually shaped...
  • Astronomy Picture of the Day -- Two Black Holes Dancing in 3C 75

    09/27/2014 9:50:48 PM PDT · by SunkenCiv · 22 replies
    NASA ^ | September 28, 2014 | (see photo credit)
    Explanation: What's happening at the center of active galaxy 3C 75? The two bright sources at the center of this composite x-ray (blue)/ radio (pink) image are co-orbiting supermassive black holes powering the giant radio source 3C 75. Surrounded by multimillion degree x-ray emitting gas, and blasting out jets of relativistic particles the supermassive black holes are separated by 25,000 light-years. At the cores of two merging galaxies in the Abell 400 galaxy cluster they are some 300 million light-years away. Astronomers conclude that these two supermassive black holes are bound together by gravity in a binary system in part...
  • Astronomy Picture of the Day -- A Launch and a Landing

    09/27/2014 9:46:34 PM PDT · by SunkenCiv · 1 replies
    NASA ^ | September 27, 2014 | (see photo credit)
    Explanation: Taken from an Atlantic beach, Cape Canaveral, planet Earth, four identically framed digital images are combined in this night skyscape. Slightly shifted short star trails dot the sky, but the exposure times were adjusted to follow the flight of a Falcon 9 rocket. The September 21 launch delivered a Dragon X capsule filled with supplies to the International Space Station. Above the bright flare seen just after launch, the rocket's first stage firing trails upward from the left. After separation, the second stage burn begins near center with the vehicle climbing toward low Earth orbit. At the horizon, the...
  • Astronomy Picture of the Day -- MAVEN at Mars

    09/27/2014 9:45:04 PM PDT · by SunkenCiv · 4 replies
    NASA ^ | September 26, 2014 | (see photo credit)
    Explanation: Launched on November 18, 2013, the MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft completed its interplanetary voyage September 21, captured into a wide, elliptical orbit around Mars. MAVEN's imaging ultraviolet spectrograph has already begun its planned exploration of the Red Planet's upper atmosphere, acquiring this image data from an altitude of 36,500 kilometers. In false color, the three ultraviolet wavelength bands show light reflected from atomic hydrogen (in blue), atomic oxygen (in green) and the planet's surface (in red). Low mass atomic hydrogen is seen to extend thousands of kilometers into space, with the cloud of more massive oxygen...
  • Astronomy Picture of the Day -- NGC 206 and the Star Clouds of Andromeda

    09/27/2014 9:40:49 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | September 25, 2014 | (see photo credit)
    Explanation: The large stellar association cataloged as NGC 206 is nestled within the dusty arms of the neighboring Andromeda galaxy. Also known as M31, the spiral galaxy is a mere 2.5 million light-years away. NGC 206 is near top center in this gorgeous close-up of the southwestern extent of Andromeda's disk, a remarkable composite of data from space and ground-based observatories. The bright, blue stars of NGC 206 indicate its youth. In fact, its youngest massive stars are less than 10 million years old. Much larger than the open or galactic clusters of young stars in the disk of our...
  • Astronomy Picture of the Day -- The Lagoon Nebula in Stars Dust and Gas

    09/27/2014 9:37:39 PM PDT · by SunkenCiv · 2 replies
    NASA ^ | September 24, 2014 | (see photo credit)
    Explanation: The large majestic Lagoon Nebula is home for many young stars and hot gas. Spanning 100 light years across while lying only about 5000 light years distant, the Lagoon Nebula is so big and bright that it can be seen without a telescope toward the constellation of Sagittarius. Many bright stars are visible from NGC 6530, an open cluster that formed in the nebula only several million years ago. The greater nebula, also known as M8 and NGC 6523, is named "Lagoon" for the band of dust seen to the left of the open cluster's center. A bright knot...
  • Astronomy Picture of the Day -- Aurora and Volcanic Light Pillar

    09/27/2014 9:35:32 PM PDT · by SunkenCiv · 2 replies
    NASA ^ | September 23, 2014 | (see photo credit)
    Explanation: That's no sunset. And that thin red line just above it -- that's not a sun pillar. The red glow on the horizon originates from a volcanic eruption, and the red line is the eruption's reflection from fluttering atmospheric ice crystals. This unusual volcanic light pillar was captured over Iceland earlier this month. The featured scene looks north from Jökulsárlón toward the erupting volcano Bárðarbunga in the Holuhraun lava field. Even the foreground sky is picturesque, with textured grey clouds in the lower atmosphere, shimmering green aurora in the upper atmosphere, and bright stars far in the distance. Although...
  • Astronomy Picture of the Day -- Earth at Equinox

    09/27/2014 9:33:13 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | September 22, 2014 | (see photo credit)
    Explanation: Earth is at equinox. Over the next 24 hours, day and night have nearly equal duration all over planet Earth. Technically, equinox transpires at 2:29 am Universal Time tomorrow, but this occurs today in North and South America. This September equinox signal that winter is approaching in the northern hemisphere, and summer is approaching in the south. At equinox, the dividing line between the sunlit half of Earth and the nighttime half of Earth temporarily passes through Earth's north and south spin poles. This dividing line is shown in clear detail in the featured video, taken by the Russian...
  • Astronomy Picture of the Day -- Saturn at Equinox

    09/21/2014 6:35:14 AM PDT · by SunkenCiv · 18 replies
    NASA ^ | September 21, 2014 | (see photo credit)
    Explanation: How would Saturn look if its ring plane pointed right at the Sun? Before August 2009, nobody knew. Every 15 years, as seen from Earth, Saturn's rings point toward the Earth and appear to disappear. The disappearing rings are no longer a mystery -- Saturn's rings are known to be so thin and the Earth is so near the Sun that when the rings point toward the Sun, they also point nearly edge-on at the Earth. Fortunately, in this third millennium, humanity is advanced enough to have a spacecraft that can see the rings during equinox from the side....
  • Astronomy Picture of the Day -- Shoreline of the Universe

    09/20/2014 12:38:21 PM PDT · by SunkenCiv · 4 replies
    NASA ^ | September 20, 2014 | (see photo credit)
    Explanation: Against dark rifts of interstellar dust, the ebb and flow of starlight along the Milky Way looks like waves breaking on a cosmic shore in this night skyscape. Taken with a digital camera from the dunes of Hatteras Island, North Carolina, planet Earth, the monochrome image is reminiscent of the time when sensitive black and white film was a popular choice for dimmly lit night- and astro-photography. Looking south, the bright stars of Sagittarius and Scorpius are near the center of the frame. Wandering Mars, Saturn, and Zubenelgenubi (Alpha Librae) form the compact triangle of bright celestial beacons farther...
  • Astronomy Picture of the Day -- Potentially Habitable Moons

    09/20/2014 12:35:22 PM PDT · by SunkenCiv · 31 replies
    NASA ^ | September 19, 2014 | (see photo credit)
    Explanation: For astrobiologists, these may be the four most tantalizing moons in our Solar System. Shown at the same scale, their exploration by interplanetary spacecraft has launched the idea that moons, not just planets, could have environments supporting life. The Galileo mission to Jupiter discovered Europa's global subsurface ocean of liquid water and indications of Ganymede's interior seas. At Saturn, the Cassini probe detected erupting fountains of water ice from Enceladus indicating warmer subsurface water on even that small moon, while finding surface lakes of frigid but still liquid hydrocarbons beneath the dense atmosphere of large moon Titan. Now looking...
  • Astronomy Picture of the Day -- Cocoon Nebula Wide Field

    09/20/2014 12:30:18 PM PDT · by SunkenCiv · 1 replies
    NASA ^ | September 18, 2014 | (see photo credit)
    Explanation: In this crowded starfield covering over 2 degrees within the high flying constellation Cygnus, the eye is drawn to the Cocoon Nebula. A compact star forming region, the cosmic Cocoon punctuates a long trail of obscuring interstellar dust clouds. Cataloged as IC 5146, the nebula is nearly 15 light-years wide, located some 4,000 light years away. Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by the young, hot stars and blue, dust-reflected starlight at the edge of an otherwise invisible molecular cloud. In fact, the bright star near the center of this nebula...
  • Astronomy Picture of the Day -- Aurora over Maine

    09/20/2014 12:27:48 PM PDT · by SunkenCiv · 3 replies
    NASA ^ | September 17, 2014 | (see photo credit)
    Explanation: It has been a good week for auroras. Earlier this month active sunspot region 2158 rotated into view and unleashed a series of flares and plasma ejections into the Solar System during its journey across the Sun's disk. In particular, a pair of Coronal Mass Ejections (CMEs) impacted the Earth's magnetosphere toward the end of last week, creating the most intense geomagnetic storm so far this year. Although power outages were feared by some, the most dramatic effects of these impacting plasma clouds were auroras seen as far south as Wisconsin, USA. In the featured image taken last Friday...
  • Astronomy Picture of the Day -- Milky Way above Atacama Salt Lagoon

    09/20/2014 12:24:41 PM PDT · by SunkenCiv · 8 replies
    NASA ^ | September 16, 2014 | (see photo credit)
    Explanation: Galaxies, stars, and a serene reflecting pool combine to create this memorable land and skyscape. The featured panorama is a 12-image mosaic taken last month from the Salar de Atacama salt flat in northern Chile. The calm water is Laguna Cejar, a salty lagoon featuring a large central sinkhole. On the image left, the astrophotographer's fiancee is seen capturing the same photogenic scene. The night sky is lit up with countless stars, the Large and Small Magellanic Cloud galaxies on the left, and the band of our Milky Way galaxy running diagonally up the right. The Milky Way may...
  • Astronomy Picture of the Day -- 62 Kilometers above Comet Churyumov-Gerasimenko

    09/14/2014 10:40:53 PM PDT · by SunkenCiv · 15 replies
    NASA ^ | September 15, 2014 | (see photo credit)
    Explanation: Spacecraft Rosetta continues to approach, circle, and map Comet Churyumov-Gerasimenko. Crossing the inner Solar System for ten years to reach the vicinity of the comet last month, the robotic spacecraft continues to image the unusual double-lobed comet nucleus. The reconstructed-color image featured, taken about 10 days ago, indicates how dark this comet nucleus is. On the average, the comet's surface reflects only about four percent of impinging visible light, making it as dark as coal. Comet 67P/Churyumov–Gerasimenko spans about four kilometers in length and has a surface gravity so low that an astronaut could jump off of it. In...
  • Astronomy Picture of the Day -- M27: The Dumbbell Nebula

    09/13/2014 9:28:43 PM PDT · by SunkenCiv · 16 replies
    NASA ^ | September 14, 2014 | (see photo credit)
    Explanation: The first hint of what will become of our Sun was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of diffuse objects not to be confused with comets. The 27th object on Messier's list, now known as M27 or the Dumbbell Nebula, is a planetary nebula, the type of nebula our Sun will produce when nuclear fusion stops in its core. M27 is one of the brightest planetary nebulae on the sky, and can be seen toward the constellation of the Fox (Vulpecula) with binoculars. It takes light about 1000 years to reach us...
  • Astronomy Picture of the Day -- Median Mashup: Hubble's Top 100

    09/13/2014 12:42:32 PM PDT · by SunkenCiv · 6 replies
    NASA ^ | September 13, 2014 | (see photo credit)
    Explanation: Now, as you sip your cosmic latte you can view 100 Hubble Space Telescope images at the same time. The popular scenes of the cosmos as captured from low Earth orbit are all combined into this single digital presentation. To make it, Hubble's top 100 images were downloaded and resized to identical pixel dimensions. At each point the 100 pixel values were arranged from lowest to highest, and the middle or median value was chosen for the final image. The combined image results in a visual abstraction - light from across the Universe surrounded by darkness.
  • Astronomy Picture of the Day -- Supernova Remnant Puppis A

    09/13/2014 12:40:55 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | September 12, 2014 | (see photo credit)
    Explanation: Driven by the explosion of a massive star, supernova remnant Puppis A is blasting into the surrounding interstellar medium about 7,000 light-years away. At that distance, this remarkable false-color exploration of its complex expansion is about 180 light-years wide. It is based on the most complete X-ray data set so far from the Chandra and XMM/Newton observations, and infrared data from the Spitzer Space Telescope. In blue hues, the filamentary X-ray glow is from gas heated by the supernova's shock wave, while the infrared emission shown in red and green is from warm dust. The bright pastel tones trace...
  • Astronomy Picture of the Day -- Zodiacal Light before Dawn

    09/13/2014 12:36:34 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | September 11, 2014 | (see photo credit)
    Explanation: You might not guess it, but sunrise was still hours away when this nightscape was taken, a view along the eastern horizon from a remote location in Chile's Atacama desert. Stretching high into the otherwise dark, starry sky the unusually bright conical glow is sunlight though, scattered by dust along the solar system's ecliptic plane . Known as Zodiacal light, the apparition is also nicknamed the "false dawn". Near center, bright star Aldebaran and the Pleiades star cluster seem immersed in the Zodiacal light, with Orion toward the right edge of the frame. Reddish emission from NGC 1499, the...
  • Astronomy Picture of the Day -- Laniakea: Our Home Supercluster of Galaxies

    09/13/2014 12:33:34 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | September 10, 2014 | (see photo credit)
    Explanation: It is not only one of the largest structures known -- it is our home. The just-identified Laniakea Supercluster of galaxies contains thousands of galaxies that includes our Milky Way Galaxy, the Local Group of galaxies, and the entire nearby Virgo Cluster of Galaxies. The colossal supercluster is shown in the above computer-generated visualization, where green areas are rich with white-dot galaxies and white lines indicate motion towards the supercluster center. An outline of Laniakea is given in orange, while the blue dot shows our location. Outside the orange line, galaxies flow into other galatic concentrations. The Laniakea Supercluster...
  • Astronomy Picture of the Day -- An Aurora Cupcake with a Milky Way Topping

    09/13/2014 12:30:58 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | September 09, 2014 | (see photo credit)
    Explanation: This sky looked delicious. Double auroral ovals were captured above the town lights of Östersund, Sweden, last week. Pictured above, the green ovals occurred lower to the ground than violet aurora rays above, making the whole display look a bit like a cupcake. To top it off, far in the distance, the central band or our Milky Way Galaxy slants down from the upper left. The auroras were caused by our Sun ejecting plasma clouds into the Solar System just a few days before, ionized particles that subsequently impacted the magnetosphere of the Earth. Aurora displays may continue this...
  • Astronomy Picture of the Day -- Super Moon vs. Micro Moon

    09/13/2014 12:28:18 PM PDT · by SunkenCiv · 13 replies
    NASA ^ | September 08, 2014 | (see photo credit)
    Explanation: What is so super about tomorrow's supermoon? Tomorrow, a full moon will occur that appears slightly larger and brighter than usual. The reason is that the Moon's fully illuminated phase occurs within a short time from perigee - when the Moon is its closest to the Earth in its elliptical orbit. Although the precise conditions that define a supermoon vary, given one definition, tomorrow's will be the third supermoon of the year -- and the third consecutive month that a supermoon occurs. One reason supermoons are popular is because they are so easy to see -- just go outside...
  • Astronomy Picture of the Day -- Full Moon Silhouettes

    09/06/2014 10:10:29 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | September 07, 2014 | (see photo credit)
    Explanation: Have you ever watched the Moon rise? The slow rise of a nearly full moon over a clear horizon can be an impressive sight. One impressive moonrise was imaged in early 2013 over Mount Victoria Lookout in Wellington, New Zealand. With detailed planning, an industrious astrophotographer placed a camera about two kilometers away and pointed it across the lookout to where the Moon would surely soon be making its nightly debut. The above single shot sequence is unedited and shown in real time -- it is not a time lapse. People on Mount Victoria Lookout can be seen in...
  • Astronomy Picture of the Day -- Moonbow Beach

    09/06/2014 4:52:36 AM PDT · by SunkenCiv · 6 replies
    NASA ^ | September 06, 2014 | (see photo credit)
    Explanation: Like a rainbow at night, a beautiful moonbow shines above the western horizon in this deserted beach scene from Molokai Island, Hawaii, USA, planet Earth. Captured last June 17 in early morning hours, the lights along the horizon are from Honolulu and cities on the island of Oahu some 30 miles away. So where was the Moon? A rainbow is produced by sunlight internally reflected in rain drops from the direction opposite the Sun back toward the observer. As the light passes from air to water and back to air again, longer wavelengths are refracted (bent) less than shorter...
  • Astronomy Picture of the Day -- A Sagittarius Starscape

    09/06/2014 4:49:49 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | September 05, 2014 | (see photo credit)
    Explanation: This rich starscape spans nearly 7 degrees on the sky, toward the Sagittarius spiral arm and the center of our Milky Way galaxy. A telescopic mosaic, it features well-known bright nebulae and star clusters cataloged by 18th century cosmic tourist Charles Messier. Still popular stops for skygazers M16, the Eagle (far right), and M17, the Swan (near center) nebulae are the brightest star-forming emission regions. With wingspans of 100 light-years or so, they shine with the telltale reddish glow of hydrogen atoms from over 5,000 light-years away. Colorful open star cluster M25 near the upper left edge of the...
  • Astronomy Picture of the Day -- Cloud, Clusters and

    09/04/2014 4:37:42 AM PDT · by SunkenCiv · 6 replies
    NASA ^ | September 04, 2014 | (see photo credit)
    Explanation: On October 19th, a good place to watch Comet Siding Spring will be from Mars. Then, this inbound visitor (C/2013 A1) to the inner solar system, discovered in January 2013 by Robert McNaught at Australia's Siding Spring Observatory, will pass within 132,000 kilometers of the Red Planet. That's a near miss, equivalent to just over 1/3 the Earth-Moon distance. Great views of the comet for denizens of planet Earth's southern hemisphere are possible now, though. This telescopic snapshot from August 29 captured the comet's whitish coma and arcing dust tail sweeping through southern skies. The fabulous field of view...
  • Astronomy Picture of the Day -- M6: The Butterfly Cluster

    09/04/2014 4:33:28 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | September 03, 2014 | (see photo credit)
    Explanation: To some, the outline of the open cluster of stars M6 resembles a butterfly. M6, also known as NGC 6405, spans about 20 light-years and lies about 2,000 light years distant. M6, pictured above, can best be seen in a dark sky with binoculars towards the constellation of the Scorpion (Scorpius), coving about as much of the sky as the full moon. Like other open clusters, M6 is composed predominantly of young blue stars, although the brightest star is nearly orange. M6 is estimated to be about 100 million years old. Determining the distance to clusters like M6 helps...
  • Astronomy Picture of the Day -- Holometer: A Microscope into Space and Time

    09/04/2014 4:29:41 AM PDT · by SunkenCiv · 4 replies
    NASA ^ | September 02, 2014 | (see photo credit)
    Explanation: How different are space and time at very small scales? To explore the unfamiliar domain of the miniscule Planck scale -- where normally unnoticeable quantum effects might become dominant -- a newly developed instrument called the Fermilab Holometer has begun operating at the Fermi National Accelerator Laboratory (Fermilab) near Chicago, Illinois, USA. The instrument seeks to determine if slight but simultaneous jiggles of a mirror in two directions expose a fundamental type of holographic noise that always exceeds a minimum amount. Pictured above is one of the end mirrors of a Holometer prototype. Although the discovery of holographic noise...
  • Astronomy Picture of the Day -- Airglow Ripples over Tibet

    09/01/2014 12:50:51 PM PDT · by SunkenCiv · 8 replies
    NASA ^ | September 01, 2014 | (see photo credit)
    Explanation: Why would the sky look like a giant target? Airglow. Following a giant thunderstorm over Bangladesh in late April, giant circular ripples of glowing air appeared over Tibet, China, as pictured above. The unusual pattern is created by atmospheric gravity waves, waves of alternating air pressure that can grow with height as the air thins, in this case about 90 kilometers up. Unlike auroras powered by collisions with energetic charged particles and seen at high latitudes, airglow is due to chemiluminescence, the production of light in a chemical reaction. More typically seen near the horizon, airglow keeps the night...
  • Astronomy Picture of the Day -- Space Shuttle and Space Station Photographed Together

    08/30/2014 11:05:59 PM PDT · by SunkenCiv · 25 replies
    NASA ^ | August 31, 2014 | (see photo credit)
    Explanation: How was this picture taken? Usually, pictures of the shuttle, taken from space, are snapped from the space station. Commonly, pictures of the space station are snapped from the shuttle. How, then, can there be a picture of both the shuttle and the station together, taken from space? The answer is that during the Space Shuttle Endeavour's last trip to the International Space Station in 2011 May, a supply ship departed the station with astronauts that captured a series of rare views. The supply ship was the Russian Soyuz TMA-20 which landed in Kazakhstan later that day. The above...