Astronomy Picture of the Day (General/Chat)

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  • Astronomy Picture of the Day -- Orion Spring

    03/26/2015 3:55:10 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | March 26, 2015 | (see photo credit)
    Explanation: As spring comes to planet Earth's northern hemisphere, familiar winter constellation Orion sets in early evening skies and budding trees frame the Hunter's stars. The yellowish hue of cool red supergiant Alpha Orionis, the great star Betelgeuse, mingles with the branches at the top of this colorful skyscape. Orion's alpha star is joined on the far right by Alpha Tauri. Also known as Aldebaran and also a giant star cooler than the Sun, it shines with a yellow light at the head of Taurus, the Bull. Contrasting blue supergiant Rigel, Beta Orionis, is Orion's other dominant star though, and...
  • Astronomy Picture of the Day -- Naked Eye Nova Sagittarii 2015 No. 2

    03/25/2015 3:30:29 PM PDT · by SunkenCiv · 8 replies
    NASA ^ | March 24, 2015 | (see photo credit)
    Explanation: It quickly went from obscurity to one of the brighter stars in Sagittarius -- but it's fading. Named Nova Sagittarii 2015 No. 2, the stellar explosion is the brightest nova visible from Earth in over a year. The featured image was captured four days ago from Ranikhet in the Indian Himalayas. Several stars in western Sagittarius make an asterism known as the Teapot, and the nova, indicated by the arrow, now appears like a new emblem on the side of the pot. As of last night, Nova Sag has faded from brighter than visual magnitude 5 to the edge...
  • Astronomy Picture of the Day -- Powers of Ten

    03/24/2015 6:17:50 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | March 24, 2015 | (see photo credit)
    Explanation: How different does the universe look on small, medium, and large scales? The most famous short science film of its generation gives breathtaking comparisons. That film, Powers of Ten, originally created in the 1960s, has now been officially posted to YouTube and embedded above. Please click the above arrow to see the nine minute movie for yourself. From a picnic blanket near Chicago out past the Virgo Cluster of Galaxies, every ten seconds the film zooms out to show a square a factor of ten times larger on each side. The video then reverses, zooming back in a factor...
  • Astronomy Picture of the Day -- Atlas V Launches MMS

    03/23/2015 4:17:58 AM PDT · by SunkenCiv · 8 replies
    NASA ^ | March 23, 2015 | (see photo credit)
    Explanation: Birds don't fly this high. Airplanes don't go this fast. The Statue of Liberty weighs less. No species other than human can even comprehend what is going on, nor could any human just a millennium ago. The launch of a rocket bound for space is an event that inspires awe and challenges description. Pictured above, an Atlas V rocket lifts off carrying NASA's Magnetospheric Multiscale Mission into Earth orbit 10 days ago to study the workings of the magnetosphere that surrounds and protects the Earth. From a standing start, the 300,000 kilogram rocket ship left to circle the Earth...
  • Astronomy Picture of the Day -- A Double Eclipse of the Sun

    03/22/2015 6:59:07 AM PDT · by SunkenCiv · 8 replies
    NASA ^ | March 22, 2015 | (see photo credit)
    Explanation: Can the Sun be eclipsed twice at the same time? Last Friday was noteworthy because part of the Earth was treated to a rare total eclipse of the Sun. But also on Friday, from a part of the Earth that only saw part of the Sun eclipsed, a second object appeared simultaneously in front of the Sun: the Earth-orbiting International Space Station. Although space station eclipses are very quick -- in this case only 0.6 seconds, they are not so rare. Capturing this composite image took a lot of planning and a little luck, as the photographer had to...
  • Astronomy Picture of the Day -- Northern Equinox Eclipse

    03/21/2015 3:39:47 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | March 21, 2015 | (see photo credit)
    Explanation: Snowy and cold is weather you might expect at the start of spring for Longyearbyen on the Arctic archipelago of Svalbard, Norway. But that turned out to be good weather for watching the Moon's umbral shadow race across northern planet Earth. The region was plunged into darkness for 3 minutes during the March 20 total solar eclipse while insulated eclipse chasers witnessed the dark Sun in the cold clear sky. In this well-timed snapshot captured near the end of totality, the Moon's shadow sweeps away from the horizon and the solar corona fades as the lunar disk just begins...
  • Astronomy Picture of the Day -- Sunshine, Earthshine

    03/20/2015 12:28:01 PM PDT · by SunkenCiv · 20 replies
    NASA ^ | March 20, 2015 | (see photo credit)
    Explanation: Today's date marks an Equinox and a New Moon. Remarkably, while the exact timing of both geocentric events occur within a span of only 13 hours, the moon also reaches its new phase only 14 hours after perigee, the closest point in its orbit. That makes the Equinox New Moon the largest New Moon of 2015, though hard to see since that lunar phase presents the Moon's dark, night side to planet Earth. Still, in this well composed image of a young lunar phase from late January you can glimpse both night and day on the lunar surface, the...
  • Astronomy Picture of the Day -- Aurora in the Backyard

    03/19/2015 4:32:59 AM PDT · by SunkenCiv · 8 replies
    NASA ^ | March 19, 2015 | (see photo credit)
    Explanation: On the night of March 17/18 this umbrella of northern lights unfolded over backyards in Vallentuna, Sweden about 30 kilometers north of Stockholm. A result of the strongest geomagnetic storm of this solar cycle, auroral displays were captured on that night from back and front yards at even lower latitudes, including sightings in the midwestern United States. A boon for aurora hunting skywatchers, the space storm began building when a coronal mass ejection, launched by solar activity some two days earlier, struck planet Earth's magnetosphere. So what's the name of the backyard observatory on the right of the wide...
  • Astronomy Picture of the Day -- Earth During a Total Eclipse of the Sun

    03/18/2015 2:42:57 PM PDT · by SunkenCiv · 15 replies
    NASA ^ | March 18, 2015 | (see photo credit)
    Explanation: What does the Earth look like during a total solar eclipse? It appears dark in the region where people see the eclipse, because that's where the shadow of the Moon falls. The shadow spot actually shoots across the Earth at nearly 2,000 kilometers per hour, darkening locations in its path for only a few minutes before moving on. The featured image shows the Earth during the total solar eclipse of 2006 March, as seen from the International Space Station. On Friday the Moon will move in front of the Sun once again, casting another distorted circular shadow that, this...
  • Astronomy Picture of the Day -- The Big Dipper Enhanced

    03/17/2015 4:35:05 AM PDT · by SunkenCiv · 12 replies
    NASA ^ | March 17, 2015 | (see photo credit)
    Explanation: Do you see it? This common question frequently precedes the rediscovery of one of the most commonly recognized configurations of stars on the northern sky: the Big Dipper. This grouping of stars is one of the few things that has likely been seen, and will be seen, by every human generation. In this featured image, however, the stars of the Big Dipper have been digitally enhanced -- they do not really appear this much brighter than nearby stars. The image was taken earlier this month from France. The Big Dipper is not by itself a constellation. Although part of...
  • Astronomy Picture of the Day -- The Clouds of Orion the Hunter

    03/16/2015 5:05:42 AM PDT · by SunkenCiv · 7 replies
    NASA ^ | March 16, 2015 | (see photo credit)
    Explanation: Cradled in cosmic dust and glowing hydrogen, stellar nurseries in Orion the Hunter lie at the edge of giant molecular clouds some 1,500 light-years away. Spanning about 30 degrees, this breath-taking vista stretches across the well-known constellation from head to toe (left to right) and beyond. At 1,500 light years away, the Great Orion Nebula is the closest large star forming region, here visible just right and below center. To its left are the Horsehead Nebula, M78, and Orion's belt stars. Sliding your cursor over the picture will also find red giant Betelgeuse at the hunter's shoulder, bright blue...
  • Astronomy Picture of the Day -- A Total Eclipse at the End of the World

    03/15/2015 9:08:26 AM PDT · by SunkenCiv · 15 replies
    NASA ^ | March 15, 2015 | (see photo credit)
    Explanation: Would you go to the end of the world to see a total eclipse of the Sun? If you did, would you be surprised to find someone else there already? In 2003, the Sun, the Moon, Antarctica, and two photographers all lined up in Antarctica during an unusual total solar eclipse. Even given the extreme location, a group of enthusiastic eclipse chasers ventured near the bottom of the world to experience the surreal momentary disappearance of the Sun behind the Moon. One of the treasures collected was the above picture -- a composite of four separate images digitally combined...
  • Astronomy Picture of the Day -- Return at Sunrise

    03/14/2015 6:29:02 AM PDT · by SunkenCiv · 7 replies
    NASA ^ | March 14, 2015 | (see photo credit)
    Explanation: Thursday, shortly after local sunrise over central Asia, this Soyuz spacecraft floated over a sea of golden clouds during its descent by parachute through planet Earth's dense atmosphere. On board were Expedition 42 commander Barry Wilmore of NASA and Alexander Samokutyaev and Elena Serova of the Russian Federal Space Agency (Roscosmos). Touch down was at approximately 10:07 p.m. EDT (8:07 a.m. March 12, Kazakh time) southeast of Zhezkazgan, Kazakhstan. The three were returning from low Earth orbit, after almost six months on the International Space Station as members of the Expedition 41 and Expedition 42 crews.
  • Astronomy Picture of the Day -- The Great Wall by Moonlight

    03/13/2015 5:01:40 AM PDT · by SunkenCiv · 6 replies
    NASA ^ | March 13, 2015 | (see photo credit)
    Explanation: Last Friday, an almost Full Moon rose as the Sun set, over this mountainous landscape north of Beijing, China. Also near apogee, the farthest point in its elliptical orbit around planet Earth, it was this year's smallest and faintest Full Moon. The Jiankou section of the Great Wall of China meanders through the scene, the ancient Great Wall itself the subject of an older-than-the-space-age myth that it would be visible to the eye when standing on the lunar surface. But even from low Earth orbit, the large scale artifact of human civilization is very difficult to identify. At its...
  • Astronomy Picture of the Day -- Along the Cygnus Wall

    03/12/2015 3:39:57 AM PDT · by SunkenCiv · 9 replies
    NASA ^ | March 12, 2015 | (see photo credit)
    Explanation: The W-shaped ridge of emission featured in this vivid skyscape is known as the Cygnus Wall. Part of a larger emission nebula with a distinctive outline popularly called The North America Nebula, the cosmic ridge spans about 20 light-years. Constructed using narrowband data to highlight the telltale reddish glow from ionized hydrogen atoms recombining with electrons, the two frame mosaic image follows an ionization front with fine details of dark, dusty forms in silhouette. Sculpted by energetic radiation from the region's young, hot, massive stars, the dark shapes inhabiting the view are clouds of cool gas and dust with...
  • Astronomy Picture of the Day -- Volcano of Fire Erupts Under the Stars

    03/11/2015 12:51:18 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | March 11, 2015 | (see photo credit)
    Explanation: First, there was an unusual smell. Then there was a loud bang. But what appeared to the eye was the most amazing of all. While waiting near midnight to see a possible eruption of Volcán de Fuego (Volcano of Fire) in Guatemala last month, a ready camera captured this extraordinary image. Lava is seen running down the side of the volcano, while ash rises up, and glowing magma bubbles explode out of the caldera. Lights near the town of Escuintla can be seen in the background, one of several nearby towns that have witnessed several spectacular eruptions previously. High...
  • Astronomy Picture of the Day -- Aurora over Icelandic Glacier

    03/10/2015 6:25:20 AM PDT · by SunkenCiv · 13 replies
    NASA ^ | March 10, 2015 | (see photo credit)
    Explanation: Several key conditions came together to create this award-winning shot. These included a dark night, few clouds, an epic auroral display, and a body of water that was both calm enough and unfrozen enough to show reflected stars. The featured skyscape of activity and serenity appeared over Iceland's Vatnajökull Glacier a year ago January, with the Jökulsárlón Iceberg Lagoon captured in the foreground. Aurora filled skies continue to be common near Earth's poles as our Sun, near Solar Maximum, continues to expel energetic clouds of plasma into the Solar System.
  • Astronomy Picture of the Day -- Galaxy and Cluster Create Four Images of Distant Supernova

    03/09/2015 3:04:25 AM PDT · by SunkenCiv · 21 replies
    NASA ^ | March 09, 2015 | (see photo credit)
    Explanation: What are the unusual spots surrounding that galaxy? They are all images of the same supernova. For the first time, a single supernova explosion has been seen split into multiple images by the gravitational lens deflections of intervening masses. In this case the masses are a large galaxy and its home galaxy cluster. The featured image was captured last November by the Earth-orbiting Hubble Space Telescope. The yellow-hued quadruply-imaged Supernova Refsdal occurred in the early universe far behind the cluster. Measuring the locations and time-delays between the supernova images should allow astrophysicists to recover the amount of dark matter...
  • Astronomy Picture of the Day -- Stars at the Galactic Center

    03/08/2015 7:09:22 AM PDT · by SunkenCiv · 10 replies
    NASA ^ | March 08, 2015 | (see photo credit)
    Explanation: The center of our Milky Way Galaxy is hidden from the prying eyes of optical telescopes by clouds of obscuring dust and gas. But in this stunning vista, the Spitzer Space Telescope's infrared cameras, penetrate much of the dust revealing the stars of the crowded galactic center region. A mosaic of many smaller snapshots, the detailed, false-color image shows older, cool stars in bluish hues. Reddish glowing dust clouds are associated with young, hot stars in stellar nurseries. The very center of the Milky Way was only recently found capable of forming newborn stars. The galactic center lies some...
  • Astronomy Picture of the Day -- NGC 602 in the Flying Lizard Nebula

    03/08/2015 7:04:57 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | March 07, 2015 | (see photo credit)
    Explanation: Near the outskirts of the Small Magellanic Cloud, a satellite galaxy some 200 thousand light-years distant, lies 5 million year young star cluster NGC 602. Surrounded by natal gas and dust, NGC 602 is just below center in this telescopic field of view with the angular size of the Full Moon on the sky. The cluster itself is about 200 light-years in diameter. Glowing interior ridges and swept back shapes strongly suggest that energetic radiation and shock waves from NGC 602's massive young stars have eroded the dusty material and triggered a progression of star formation moving away from...
  • Astronomy Picture of the Day -- An Aurora of Marbles

    03/07/2015 7:00:15 PM PST · by SunkenCiv · 5 replies
    NASA ^ | February 07, 2015 | (see photo credit)
    Explanation: It looks like a fine collection of aggies. But this grid of embedded swirls and streaks actually follows the dramatic development of planet Earth's auroral substorms. The sequence of over 600 horizon-to-horizon fisheye images was taken over a 2 hour period near the artic circle in March of 2012 from Lapland, northern Sweden. It begins at upper left in evening twilight and ends at lower right, covering two activity peaks with bright coronae forming overhead. While exploring space between Earth and Moon, NASA's fleet of THEMIS spacecraft discovered that these explosions of auroral activity are driven by sudden releases...
  • Astronomy Picture of the Day -- Jupiter Triple-Moon Conjunction

    03/07/2015 6:57:01 PM PST · by SunkenCiv · 6 replies
    NASA ^ | February 06, 2015 | (see photo credit)
    Explanation: Our solar system's ruling giant planet Jupiter and 3 of its 4 large Galilean moons are captured in this single Hubble snapshot from January 24. Crossing in front of Jupiter's banded cloud tops Europa, Callisto, and Io are framed from lower left to upper right in a rare triple-moon conjunction. Distinguishable by colors alone icy Europa is almost white, Callisto's ancient cratered surface looks dark brown, and volcanic Io appears yellowish. The transiting moons and moon shadows can be identified by sliding your cursor over the image, or following this link. Remarkably, two small, inner Jovian moons, Amalthea and...
  • Astronomy Picture of the Day -- Cometary Globule CG4

    03/06/2015 4:56:55 AM PST · by SunkenCiv · 5 replies
    NASA ^ | March 06, 2015 | (see photo credit)
    Explanation: The faint and somehow menacing cometary globule CG4 reaches through the center of this deep southern skyscape. About 1,300 light-years from Earth toward the constellation Puppis, its head is about 1.5 light-years in diameter and its tail about 8 light-years long. That's far larger than the Solar System's comets that it seems to resemble. In fact, the dusty cloud contains enough material to form several Sun-like stars and likely has ongoing star formation within. How its distinctive form came about is still debated, but its long tail trails away from the Vela Supernova remnant near the center of the...
  • Astronomy Picture of the Day -- Enhanced Color Caloris

    03/05/2015 6:18:26 AM PST · by SunkenCiv · 7 replies
    NASA ^ | March 05, 2015 | (see photo credit)
    Explanation: The sprawling Caloris basin on Mercury is one of the solar system's largest impact basins, created during the early history of the solar system by the impact of a large asteroid-sized body. The multi-featured, fractured basin spans about 1,500 kilometers in this enhanced color mosaic based on image data from the Mercury-orbiting MESSENGER spacecraft. Mercury's youngest large impact basin, Caloris was subsequently filled in by lavas that appear orange in the mosaic. Craters made after the flooding have excavated material from beneath the surface lavas. Seen as contrasting blue hues, they likely offer a glimpse of the original basin...
  • Astronomy Picture of the Day -- Pillars and Jets in the Pelican Nebula

    03/04/2015 3:02:06 PM PST · by SunkenCiv · 8 replies
    NASA ^ | March 04, 2015 | (see photo credit)
    Explanation: What dark structures arise from the Pelican Nebula? Visible as a bird-shaped nebula toward the constellation of a bird (Cygnus, the Swan), the Pelican Nebula is a place dotted with newly formed stars but fouled with dark dust. These smoke-sized dust grains formed in the cool atmospheres of young stars and were dispersed by stellar winds and explosions. Impressive Herbig-Haro jets are seen emitted by a star on the right that is helping to destroy the light year-long dust pillar that contains it. The featured image was scientifically-colored to emphasize light emitted by small amounts of ionized nitrogen, oxygen,...
  • Astronomy Picture of the Day -- A Dust Devil on Mars

    03/03/2015 3:39:47 AM PST · by SunkenCiv · 5 replies
    NASA ^ | March 03, 2015 | (see photo credit)
    Explanation: It was late in the northern martian spring when the HiRISE camera onboard the Mars Reconnaissance Orbiter spied this local denizen. Tracking across the flat, dust-covered Amazonis Planitia in 2012, the core of this whirling dust devil is about 140 meters in diameter. Lofting dust into the thin martian atmosphere, its plume reaches about 20 kilometers above the surface. Common to this region of Mars, dust devils occur as the surface is heated by the Sun, generating warm, rising air currents that begin to rotate. Tangential wind speeds of up to 110 kilometers per hour are reported for dust...
  • Astronomy Picture of the Day -- Lenticular Cloud, Moon, Mars, Venus

    03/02/2015 4:39:52 AM PST · by SunkenCiv · 21 replies
    NASA ^ | March 02, 2015 | (see photo credit)
    Explanation: It is not every day that such an interesting cloud photobombs your image. The original plan was to photograph a rare angular conjunction of Mars and Venus that occurred a week and a half ago, with the added bonus of a crescent Moon and the International Space Station (ISS) both passing nearby. Unfortunately, on Madeira Island, Portugal, this event was clouded out. During the next day, however, a spectacular lenticular cloud appeared before sunset, so the industrious astrophotographer quickly formulated a new plan. A close look at the resulting image reveals the Moon visible toward the left of the...
  • Astronomy Picture of the Day -- Inside the Coma Cluster of Galaxies

    03/01/2015 8:36:27 AM PST · by SunkenCiv · 3 replies
    NASA ^ | March 01, 2015 | (see photo credit)
    Explanation: Almost every object in the above photograph is a galaxy. The Coma Cluster of Galaxies pictured above is one of the densest clusters known - it contains thousands of galaxies. Each of these galaxies houses billions of stars - just as our own Milky Way Galaxy does. Although nearby when compared to most other clusters, light from the Coma Cluster still takes hundreds of millions of years to reach us. In fact, the Coma Cluster is so big it takes light millions of years just to go from one side to the other! The above mosaic of images of...
  • Astronomy Picture of the Day -- Moon-Venus-Mars Skyline

    02/28/2015 6:26:34 AM PST · by SunkenCiv · 5 replies
    NASA ^ | February 28, 2015 | (see photo credit)
    Explanation: Taken on February 20, five different exposures made in rapid succession were used to created this tantalizing telephoto image. In combination, they reveal a wide range of brightness visible to the eye on that frigid evening, from the urban glow of the Quebec City skyline to the triple conjunction of Moon, Venus and Mars. Shortly after sunset the young Moon shows off its bright crescent next to brilliant Venus. Fainter Mars is near the top of the frame. Though details in the Moon's sunlit crescent are washed out, features on the dark, shadowed part of the lunar disk are...
  • Astronomy Picture of the Day -- Long Lovejoy and Little Dumbbell

    02/27/2015 4:58:58 AM PST · by SunkenCiv · 2 replies
    NASA ^ | February 27, 2015 | (see photo credit)
    Explanation: Buffeted by the solar wind, Comet Lovejoy's crooked ion tail stretches over 3 degrees across this telescopic field of view, recorded on February 20. The starry background includes awesome bluish star Phi Persei below, and pretty planetary nebula M76 just above Lovejoy's long tail. Also known as the Little Dumbbell Nebula, after its brighter cousin M27 the Dumbbell Nebula, M76 is only a Full Moon's width away from the comet's greenish coma. Still shining in northern hemisphere skies, this Comet Lovejoy (C/2014 Q2) is outbound from the inner solar system some 10 light-minutes or 190 million kilometers from Earth....
  • Astronomy Picture of the Day -- Love and War by Moonlight

    02/26/2015 6:11:35 AM PST · by SunkenCiv · 5 replies
    NASA ^ | February 26, 2015 | (see photo credit)
    Explanation: Venus, named for the Roman goddess of love, and Mars, the war god's namesake, came together by moonlight in this lovely skyview, recorded on February 20 from Charleston, South Carolina, USA, planet Earth. Made in twilight with a digital camera, the three second time exposure also records earthshine illuminating the otherwise dark surface of the young crescent Moon. Of course, the Moon has moved on from this much anticipated triple conjunction. Venus still shines in the west though as the evening star, third brightest object in Earth's sky, after the Sun and the Moon itself. Seen here within almost...
  • Astronomy Picture of the Day -- The Rosette Nebula in Hydrogen and Oxygen

    02/25/2015 5:25:27 AM PST · by SunkenCiv · 4 replies
    NASA ^ | February 25, 2015 | (see photo credit)
    Explanation: The Rosette Nebula is not the only cosmic cloud of gas and dust to evoke the imagery of flowers -- but it is the most famous. At the edge of a large molecular cloud in Monoceros, some 5,000 light years away, the petals of this rose are actually a stellar nursery whose lovely, symmetric shape is sculpted by the winds and radiation from its central cluster of hot young stars. The stars in the energetic cluster, cataloged as NGC 2244, are only a few million years old, while the central cavity in the Rosette Nebula, cataloged as NGC 2237,...
  • Astronomy Picture of the Day -- Unusual Plumes Above Mars

    02/24/2015 2:18:41 PM PST · by SunkenCiv · 21 replies
    NASA ^ | February 24, 2015 | (see photo credit)
    Explanation: What is creating unusual plumes on Mars? No one is sure. Noted and confirmed by a global contingent of amateur astronomers on photos of the red planet in March 2012, possibly similar plumes have now been found on archived images as far back as 1997. Since the plumes reach 200 kilometers up, they seem too high to be related to wind-blown surface dust. Since one plume lasted for eleven days, it seemed too long lasting to be related to aurora. Amateur astronomers will surely continue to monitor the terminator and edge regions of Mars for new high plumes, and...
  • Astronomy Picture of the Day -- The Milky Way Over the Arizona Toadstools

    02/23/2015 4:01:33 AM PST · by SunkenCiv · 9 replies
    NASA ^ | February 23, 2015 | (see photo credit)
    Explanation: Which is older -- the rocks you see on the ground or the light you see from the sky? Usually it's the rocks that are older, with their origin sentiments deposited well before light left any of the stars or nebulas you see in the sky. However, if you can see, through a telescope, a distant galaxy far across the universe -- further than Andromeda or spiral galaxy NGC 7331 (inset) -- then you are seeing light even more ancient. Featured here, the central disk of our Milky Way Galaxy arches over Toadstool hoodoos rock formations in northern Arizona,...
  • Astronomy Picture of the Day -- The Dark River to Antares

    02/22/2015 8:59:45 AM PST · by SunkenCiv · 6 replies
    NASA ^ | February 22, 2015 | (see photo credit)
    Explanation: Connecting the Pipe Nebula to the colorful region near bright star Antares is a dark cloud dubbed the Dark River, flowing from the picture's left edge. Murky looking, the Dark River's appearance is caused by dust obscuring background starlight, although the dark nebula contains mostly hydrogen and molecular gas. Surrounded by dust, Antares, a red supergiant star, creates an unusual bright yellowish reflection nebula. Above it, bright blue double star Rho Ophiuchi is embedded in one of the more typical bluish reflection nebulae, while red emission nebulae are also scattered around the region. Globular star cluster M4 is just...
  • Astronomy Picture of the Day -- 45 Days in the Sun

    02/21/2015 8:26:45 AM PST · by SunkenCiv · 25 replies
    NASA ^ | February 21, 2015 | (see photo credit)
    Explanation: From January 11 to February 25 2013, a pinhole camera sat in a field near Budapest, Hungary, planet Earth to create this intriguing solargraph. And for 45 days, an old Antonov An-2 biplane stood still while the Sun rose and set. The camera's continuous exposure began about 20 days after the northern hemispere's winter solstice, so each day the Sun's trail arcs steadily higher through the sky. These days in the Sun were recorded on a piece of black and white photosensitive paper tucked in to the simple plastic film container. The long exposure produced a visible color image...
  • Astronomy Picture of the Day -- An Evening Sky Conjunction

    02/20/2015 2:29:54 PM PST · by SunkenCiv · 11 replies
    NASA ^ | February 20, 2015 | (see photo credit)
    Explanation: Eight years ago, an evening sky held this lovely pairing of a young crescent Moon and brilliant Venus. Seen near the western horizon, the close conjunction and its wintry reflection were captured from Bolu, Turkey, planet Earth on February 19, 2007. In the 8 Earth years since this photograph was taken Venus has orbited the Sun almost exactly 13 times, so the Sun and Venus have now returned to the same the configuration in Earth's sky. And since every 8 years the Moon also nearly repeats its phases for a given time of year, a very similar crescent Moon-Venus...
  • Astronomy Picture of the Day -- Palomar 12

    02/19/2015 5:27:30 AM PST · by SunkenCiv · 6 replies
    NASA ^ | February 19, 2015 | (see photo credit)
    Explanation: Palomar 12 was not born here. The stars of the globular cluster, first identified in the Palomar Sky Survey, are younger than those in other globular star clusters that roam the halo of our Milky Way Galaxy. Palomar 12's position in our galaxy and measured motion suggest its home was once the Sagittarius Dwarf Elliptical Galaxy, a small satellite of the Milky Way. Disrupted by gravitational tides during close encounters the satellite galaxy has lost its stars to the larger Milky Way. Now part of the Milky Way's halo, the tidal capture of Palomar 12 likely took place some...
  • Astronomy Picture of the Day -- Dark Craters and Bright Spots Revealed on Asteroid Ceres

    02/19/2015 5:22:59 AM PST · by SunkenCiv · 14 replies
    NASA ^ | February 18, 2015 | (see photo credit)
    Explanation: What are those bright spots on asteroid Ceres? As the robotic spacecraft Dawn approaches the largest asteroid in the asteroid belt, the puzzle only deepens. Sharper new images taken last week and released yesterday indicate, as expected, that most of the surface of dwarf planet Ceres is dark and heavily cratered like our Moon and the planet Mercury. The new images do not clearly indicate, however, the nature of comparatively bright spots -- although more of them are seen to exist. The enigmatic spots were first noticed on Texas-sized Ceres a few weeks ago during Dawn's approach. The intriguing...
  • Astronomy Picture of the Day -- Fibrils Flower on the Sun

    02/17/2015 5:31:12 AM PST · by SunkenCiv · 3 replies
    NASA ^ | February 17, 2015 | (see photo credit)
    Explanation: When does the Sun look like a flower? In a specific color of red light emitted by hydrogen, as featured here, some regions of the solar chromosphere may resemble a rose. The color-inverted image was taken in 2014 October and shows active solar region 2177. The petals dominating the frame are actually magnetically confined tubes of hot plasma called fibrils, some of which extend longer the diameter of the Earth. In the central region many of these fibrils are seen end-on, while the surrounding regions are typically populated with curved fibrils. When seen over the Sun's edge, these huge...
  • Astronomy Picture of the Day -- M106: A Spiral Galaxy with a Strange Center

    02/16/2015 1:52:06 AM PST · by SunkenCiv · 8 replies
    NASA ^ | February 16, 2015 | (see photo credit)
    Explanation: What's happening at the center of spiral galaxy M106? A swirling disk of stars and gas, M106's appearance is dominated by blue spiral arms and red dust lanes near the nucleus, as shown in the featured image. The core of M106 glows brightly in radio waves and X-rays where twin jets have been found running the length of the galaxy. An unusual central glow makes M106 one of the closest examples of the Seyfert class of galaxies, where vast amounts of glowing gas are thought to be falling into a central massive black hole. M106, also designated NGC 4258,...
  • Astronomy Picture of the Day -- Two Hours Before Neptune

    02/15/2015 10:21:38 AM PST · by SunkenCiv · 7 replies
    NASA ^ | February 15, 2015 | (see photo credit)
    Explanation: Two hours before closest approach to Neptune in 1989, the Voyager 2 robot spacecraft snapped this picture. Clearly visible for the first time were long light-colored cirrus-type clouds floating high in Neptune's atmosphere. Shadows of these clouds can even be seen on lower cloud decks. Most of Neptune's atmosphere is made of hydrogen and helium, which is invisible. Neptune's blue color therefore comes from smaller amounts of atmospheric methane, which preferentially absorbs red light. Neptune has the fastest winds in the Solar System, with gusts reaching 2000 kilometers per hour. Speculation holds that diamonds may be created in the...
  • Astronomy Picture of the Day -- Solar System Portrait

    02/14/2015 5:10:04 AM PST · by SunkenCiv · 7 replies
    NASA ^ | February 14, 2015 | (see photo credit)
    Explanation: On another Valentine's Day 25 years ago, cruising four billion miles from the Sun, the Voyager 1 spacecraft looked back one last time to make this first ever Solar System family portrait. The complete portrait is a 60 frame mosaic made from a vantage point 32 degrees above the ecliptic plane. In it, Voyager's wide angle camera frames sweep through the inner Solar System at the left, linking up with gas giant Neptune, the Solar System's outermost planet, at the far right. Positions for Venus, Earth, Jupiter, Saturn, Uranus, and Neptune are indicated by letters, while the Sun is...
  • Astronomy Picture of the Day -- Aurora on Ice

    02/13/2015 5:49:51 AM PST · by SunkenCiv · 5 replies
    NASA ^ | February 13, 2015 | (see photo credit)
    Explanation: Not from a snowglobe, this expansive fisheye view of ice and sky was captured on February 1, from Jökulsárlón Beach, southeast Iceland, planet Earth. Chunks of glacial ice on the black sand beach glisten in the light of a nearly full moon surrounded by a shining halo. The 22 degree lunar halo itself is created by ice crystals in high, thin clouds refracting the moonlight. Despite the bright moonlight, curtains of aurora still dance through the surreal scene. In early February, their activity was triggered by Earth's restless magnetosphere and the energetic wind from a coronal hole near the...
  • Astronomy Picture of the Day -- Exploring the Antennae

    02/12/2015 6:29:51 AM PST · by SunkenCiv · 8 replies
    NASA ^ | February 12, 2015 | (see photo credit)
    Explanation: Some 60 million light-years away in the southerly constellation Corvus, two large galaxies are colliding. The stars in the two galaxies, cataloged as NGC 4038 and NGC 4039, very rarely collide in the course of the ponderous cataclysm, lasting hundreds of millions of years. But their large clouds of molecular gas and dust often do, triggering furious episodes of star formation near the center of the cosmic wreckage. Spanning about 500 thousand light-years, this stunning composited view also reveals new star clusters and matter flung far from the scene of the accident by gravitational tidal forces. The remarkable collaborative...
  • Astronomy Picture of the Day -- M100: A Grand Design Spiral Galaxy

    02/11/2015 4:25:57 AM PST · by SunkenCiv · 5 replies
    NASA ^ | February 11, 2015 | (see photo credit)
    Explanation: Majestic on a truly cosmic scale, M100 is appropriately known as a grand design spiral galaxy. It is a large galaxy of over 100 billion stars with well-defined spiral arms that is similar to our own Milky Way Galaxy. One of the brightest members of the Virgo Cluster of galaxies, M100 (alias NGC 4321) is 56 million light-years distant toward the constellation of Berenice's Hair (Coma Berenices). This Hubble Space Telescope image of M100 was made in 2006 and reveals bright blue star clusters and intricate winding dust lanes which are hallmarks of this class of galaxies. Studies of...
  • Astronomy Picture of the Day -- An Extremely Long Filament on the Sun

    02/10/2015 8:06:12 AM PST · by SunkenCiv · 11 replies
    NASA ^ | February 10, 2015 | (see photo credit)
    Explanation: Yesterday, the Sun exhibited one of the longest filaments ever recorded. It may still be there today. Visible as the dark streak just below the center in the featured image, the enormous filament extended across the face of the Sun a distance even longer than the Sun's radius -- over 700,000 kilometers. A filament is actually hot gas held aloft by the Sun's magnetic field, so that viewed from the side it would appear as a raised prominence. The featured image shows the filament in light emitted by hydrogen and therefore highlights the Sun's chromosphere. Sun-following telescopes including NASA's...
  • Astronomy Picture of the Day -- Layered Rocks near Mount Sharp on Mars

    02/09/2015 6:31:47 AM PST · by SunkenCiv · 24 replies
    NASA ^ | February 09, 2015 | (see photo credit)
    Explanation: What caused these Martian rocks to be layered? The leading hypothesis is an ancient Martian lake that kept evaporating and refilling over 10 million years -- but has now remained dry and empty of water for billions of years. The featured image, taken last November by the robotic Curiosity rover, shows one-meter wide Whale Rock which is part of the Pahrump Hills outcrop at the base of Mount Sharp. Also evident in the image is cross-bedding -- rock with angled layers -- which were likely facilitated by waves of sand. Curiosity continues to find many layered rocks like this...
  • Astronomy Picture of the Day -- Carina Nebula Dust Pillar

    02/08/2015 10:30:15 AM PST · by SunkenCiv · 6 replies
    NASA ^ | February 08, 2015 | (see photo credit)
    Explanation: This cosmic pillar of gas and dust is nearly two light-years wide. The structure lies within one of our galaxy's largest star forming regions, the Carina Nebula, shining in southern skies at a distance of about 7,500 light-years. The pillar's convoluted outlines are shaped by the winds and radiation of Carina's young, hot, massive stars. But the interior of the cosmic pillar itself is home to stars in the process of formation. In fact, a penetrating infrared view shows the pillar is dominated by two, narrow, energetic jets blasting outward from a still hidden infant star. The above featured...
  • Astronomy Picture of the Day -- An Aurora of Marbles

    02/07/2015 5:07:47 AM PST · by SunkenCiv · 10 replies
    NASA ^ | February 07, 2015 | (see photo credit)
    Explanation: It looks like a fine collection of aggies. But this grid of embedded swirls and streaks actually follows the dramatic development of planet Earth's auroral substorms. The sequence of over 600 horizon-to-horizon fisheye images was taken over a 2 hour period near the artic circle in March of 2012 from Lapland, northern Sweden. It begins at upper left in evening twilight and ends at lower right, covering two activity peaks with bright coronae forming overhead. While exploring space between Earth and Moon, NASA's fleet of THEMIS spacecraft discovered that these explosions of auroral activity are driven by sudden releases...