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Astronomy Picture of the Day (General/Chat)

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  • Astronomy Picture of the Day -- The Great Carina Nebula

    10/15/2013 8:09:31 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | October 15, 2013 | (see photo credit)
    Explanation: A jewel of the southern sky, the Great Carina Nebula, also known as NGC 3372, spans over 300 light-years, one of our galaxy's largest star forming regions. Like the smaller, more northerly Great Orion Nebula, the Carina Nebula is easily visible to the unaided eye, though at a distance of 7,500 light-years it is some 5 times farther away. This gorgeous telescopic portrait reveals remarkable details of the region's glowing filaments of interstellar gas and obscuring cosmic dust clouds. Wider than the Full Moon in angular size, the field of view stretches over 300 light-years across the nebula. The...
  • Astronomy Picture of the Day -- High Noon Analemma Over Azerbaijan

    10/13/2013 9:13:25 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | October 14, 2013 | (see photo credit)
    Explanation: Is the Sun always straight up at noontime? No. For example, the Sun never appears directly overhead from locations well north or south of the Earth's equator. Conversely, there is always a place on Earth where the Sun will appear at zenith at noon -- for example on the equator during an equinox. Turning the problem around, however, as in finding where the Sun actually appears to be at high noon, is as easy as waiting for midday, pointing your camera up, and taking a picture. If you do this often enough, you find that as the days march...
  • Astronomy Picture of the Day -- Hale-Bopp: The Great Comet of 1997

    10/13/2013 3:50:25 PM PDT · by SunkenCiv · 19 replies
    NASA ^ | October 13, 2013 | (see photo credit)
    Explanation: Sixteen years ago, Comet Hale-Bopp rounded the Sun and offered a dazzling spectacle in planet Earth's night. This stunning view, recorded shortly after the comet's 1997 perihelion passage, features the memorable tails of Hale-Bopp -- a whitish dust tail and blue ion tail. Here, the ion tail extends well over ten degrees across the northern sky, fading near the double star clusters in Perseus, while the head of the comet lies near Almach, a bright star in the constellation Andromeda. Do you remember Hale-Bopp? The photographer's sons do, pictured in the foreground at ages 12 and 15. In all,...
  • Astronomy Picture of the Day -- Cometary Globules

    10/12/2013 11:19:19 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | October 12, 2013 | (see photo credit)
    Explanation: Bright-rimmed, flowing shapes gather near the center of this rich starfield toward the boarders of the nautical southern constellations Pupis and Vela. Composed of interstellar gas and dust, the grouping of light-year sized cometary globules is about 1300 light-years distant. Energetic ultraviolet light from nearby hot stars has molded the globules and ionized their bright rims. The globules also stream away from the Vela supernova remnant which may have influenced their swept-back shapes. Within them, cores of cold gas and dust are likely collapsing to form low mass stars, whose formation will ultimately cause the globules to disperse. In...
  • Astronomy Picture of the Day -- NGC 891 Edge-on

    10/10/2013 9:29:30 PM PDT · by SunkenCiv · 12 replies
    NASA ^ | October 11, 2013 | (see photo credit)
    Explanation: This sharp cosmic portrait features NGC 891. The spiral galaxy spans about 100 thousand light-years and is seen almost exactly edge-on from our perspective. In fact, about 30 million light-years distant in the constellation Andromeda, NGC 891 looks a lot like our Milky Way. At first glance, it has a flat, thin, galactic disk and a central bulge cut along the middle by regions of dark obscuring dust. The combined image data also reveal the galaxy's young blue star clusters and telltale pinkish star forming regions. And remarkably apparent in NGC 891's edge-on presentation are filaments of dust that...
  • Astronomy Picture of the Day -- M78: Stardust and Starlight

    10/10/2013 9:28:41 PM PDT · by SunkenCiv · 4 replies
    NASA ^ | October 10, 2013 | (see photo credit)
    Explanation: Interstellar dust clouds and bright nebulae abound in the fertile constellation of Orion. One of the brightest, M78, is just left of center in this colorful telescopic view, covering an area north of Orion's belt. At a distance of about 1,500 light-years, the bluish nebula itself is about 5 light-years across. Its blue tint is due to dust preferentially reflecting the blue light of hot, young stars in the region. Dark dust lanes and other nebulae can easily be traced through this gorgeous skyscape. The scene also includes the remarkable McNeil's Nebula -- a newly recognized nebula associated with...
  • Astronomy Picture of the Day -- Arp 94

    10/10/2013 9:26:04 PM PDT · by SunkenCiv · 4 replies
    NASA ^ | October 09, 2013 | (see photo credit)
    Explanation: This telescopic snapshot records a cosmic moment in the tumultuous lives of large spiral galaxy NGC 3227 and smaller elliptical NGC 3226. Catching them in the middle of an ongoing gravitational dance, the sensitive imaging also follows faint tidal star streams flung from the galaxies in their repeated close encounters. Over 50 million light-years distant toward the constellation Leo, the pair's appearance has earned them the designation Arp 94 in the classic catalog of peculiar galaxies. But such galactic collisions and mergers are now thought to represent a normal course in the evolution of galaxies, including our own Milky...
  • Astronomy Picture of the Day -- The Bubble and M52

    10/10/2013 9:25:15 PM PDT · by SunkenCiv · 3 replies
    NASA ^ | October 08, 2013 | (see photo credit)
    Explanation: To the eye, this cosmic composition nicely balances the Bubble Nebula at the lower left with open star cluster M52 above it and to the right. The pair would be lopsided on other scales, though. Embedded in a complex of interstellar dust and gas and blown by the winds from a single, massive O-type star, the Bubble Nebula, also known as NGC 7635, is a mere 10 light-years wide. On the other hand, M52 is a rich open cluster of around a thousand stars. The cluster is about 25 light-years across. Seen toward the northern boundary of Cassiopeia, distance...
  • Astronomy Picture of the Day -- Comet ISON Approaches

    10/10/2013 9:24:38 PM PDT · by SunkenCiv · 20 replies
    NASA ^ | October 07, 2013 | (see photo credit)
    Explanation: How impressive will Comet ISON become? No one is sure, but unfortunately, as the comet approaches the inner Solar System, it is brightening more slowly than many early predictions. Pictured above, Comet ISON is seen about two weeks ago as it continued to develop a tail. Last week the comet passed relatively close to Mars, and was directly imaged by the Mars Reconnaissance Orbiter. When Comet ISON dives to within a few solar radii of the Sun's surface in late November, it may become brighter than the Moon and sport a long and flowing tail -- or it may...
  • Astronomy Picture of the Day -- Hubble Remix: Active Galaxy NGC 1275

    10/06/2013 12:09:38 PM PDT · by SunkenCiv · 4 replies
    NASA ^ | October 06, 2013 | (see photo credit)
    Explanation: Active galaxy NGC 1275 is the central, dominant member of the large and relatively nearby Perseus Cluster of Galaxies. Wild-looking at visible wavelengths, the active galaxy is also a prodigious source of x-rays and radio emission. NGC 1275 accretes matter as entire galaxies fall into it, ultimately feeding a supermassive black hole at the galaxy's core. This color composite image, recreated from archival Hubble Space Telescope data, highlights the resulting galactic debris and filaments of glowing gas, some up to 20,000 light-years long. The filaments persist in NGC 1275, even though the turmoil of galactic collisions should destroy them....
  • Astronomy Picture of the Day -- October Aurora in Prairie Skies

    10/05/2013 6:46:48 PM PDT · by SunkenCiv · 8 replies
    NASA ^ | October 05, 2013 | (see photo credit)
    Explanation: Wind and spaceweather are transformed in this haunting night skyscape. The prairie windmill and colorful auroral display were captured on October 1, from central South Dakota, USA, as a good season for aurora hunters came with longer autumn nights. From green to rarer reddish hues, the northern lights are sparked by the geomagnetic storms caused by solar activity. These extend far above the cloud bank to altitudes well over 100 kilometers, against the backdrop of distant stars in the northern night. Visual double star Mizar, marking the middle of the Big Dipper's handle, is easy to spot at the...
  • Astronomy Picture of the Day -- The Densest Galaxy

    10/05/2013 6:46:19 PM PDT · by SunkenCiv · 8 replies
    NASA ^ | October 04, 2013 | (see photo credit)
    Explanation: The bright core and outer reaches of giant elliptical galaxy M60 (NGC 4649) loom large at the upper left of this sharp close-up from the Hubble Space Telescope. Some 54 million light-years away and 120,000 light-years across, M60 is one of the largest galaxies in the nearby Virgo Cluster. In cosmic contrast, the small, round smudge at picture center is now recognized as an ultra-compact dwarf galaxy. Cataloged as M60-UCD1, it may well be the densest galaxy in the nearby universe. Concentrating half of its total mass of 200 million suns into a radius of only 80 light-years, stars...
  • Astronomy Picture of the Day -- M106 Close Up

    10/03/2013 3:28:01 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | October 03, 2013 | (see photo credit)
    Explanation: Close to the Great Bear (Ursa Major) and surrounded by the stars of the Hunting Dogs (Canes Venatici), this celestial wonder was discovered in 1781 by the metric French astronomer Pierre Mechain. Later, it was added to the catalog of his friend and colleague Charles Messier as M106. Modern deep telescopic views reveal it to be an island universe: a spiral galaxy around 30 thousand light-years across located only about 21 million light-years beyond the stars of the Milky Way. Along with prominent dust lanes and a bright central core, this colorful composite image highlights youthful blue star clusters...
  • Astronomy Picture of the Day -- All the Colors of the Sun

    10/02/2013 3:37:32 AM PDT · by SunkenCiv · 15 replies
    NASA ^ | October 02, 2013 | (see photo credit)
    Explanation: It is still not known why the Sun's light is missing some colors. Here are all the visible colors of the Sun, produced by passing the Sun's light through a prism-like device. The spectrum was created at the McMath-Pierce Solar Observatory and shows, first off, that although our white-appearing Sun emits light of nearly every color, it does indeed appear brightest in yellow-green light. The dark patches in the above spectrum arise from gas at or above the Sun's surface absorbing sunlight emitted below. Since different types of gas absorb different colors of light, it is possible to determine...
  • Astronomy Picture of the Day -- Filaments of the Vela Supernova Remnant

    10/01/2013 3:19:37 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | October 01, 2013 | (see photo credit)
    Explanation: The explosion is over but the consequences continue. About eleven thousand years ago a star in the constellation of Vela could be seen to explode, creating a strange point of light briefly visible to humans living near the beginning of recorded history. The outer layers of the star crashed into the interstellar medium, driving a shock wave that is still visible today. A roughly spherical, expanding shock wave is visible in X-rays. The above image captures some of that filamentary and gigantic shock in visible light. As gas flies away from the detonated star, it decays and reacts with...
  • Astronomy Picture of the Day -- Mysterious Green Patches on the Sky

    09/30/2013 3:20:45 PM PDT · by SunkenCiv · 12 replies
    NASA ^ | September 30, 2013 | (see photo credit)
    Explanation: What is it? Some surely natural phenomenon has appeared in a video that, so far, has defied clear identification. The above time-lapse video was made to record Perseid meteors above Hopewell Rocks in New Brunswick, Canada late this summer. The video, which ran from 9:30 pm August 11 to 3:00 am the next morning, records several meteor and satellite streaks beyond a picturesque background. Each image records a 30 second exposure. At about 25 seconds into the video, however, an unusual patchy green glow appears to cover the sky. Possible explanations include airglow, aurora, lighting from an artificial or...
  • Astronomy Picture of the Day -- The Fairy of Eagle Nebula

    09/29/2013 8:43:06 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | September 29, 2013 | (see photo credit)
    Explanation: The dust sculptures of the Eagle Nebula are evaporating. As powerful starlight whittles away these cool cosmic mountains, the statuesque pillars that remain might be imagined as mythical beasts. Pictured above is one of several striking dust pillars of the Eagle Nebula that might be described as a gigantic alien fairy. This fairy, however, is ten light years tall and spews radiation much hotter than common fire. The greater Eagle Nebula, M16, is actually a giant evaporating shell of gas and dust inside of which is a growing cavity filled with a spectacular stellar nursery currently forming an open...
  • Astronomy Picture of the Day -- Equinox Earth

    09/28/2013 2:08:39 AM PDT · by SunkenCiv · 6 replies
    NASA ^ | September 28, 2013 | (see photo credit)
    Explanation: From a geostationary orbit 36,000 kilometers above the equator, Russian meteorological satellite Elektro-L takes high-resolution images our fair planet every 30 minutes. But only twice a year, during an Equinox, can it capture an image like this one, showing an entire hemisphere bathed in sunlight. At an Equinox, the Earth's axis of rotation is not tilted toward or away from the Sun, so the solar illumination can extend to both the planet's poles. Of course, this Elektro-L picture was recorded on September 22nd, at the northern hemisphere's autumnal equinox. For a moment on that date, the Sun was behind...
  • Astronomy Picture of the Day -- Andromeda on the Rocks

    09/27/2013 3:11:05 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | September 27, 2013 | (see photo credit)
    Explanation: How far can you see? The Andromeda Galaxy 2.5 million light years away is the most distant object easily seen by the unaided eye. Other apparent denizens of the night sky, stars, clusters, and nebulae, typically range from a few hundred to a few thousand light-years away and lie well within our own Milky Way Galaxy. Also known as M31, the Andromeda Galaxy is the faint smudge near top center of this Earth and skyscape, taken from eastern Italy, near Monte Conero on the Adriatic sea coast. From a few centimeters to a few million light-years, the picture demonstrates...
  • Astronomy Picture of the Day -- M31 versus M33

    09/26/2013 6:34:06 PM PDT · by SunkenCiv · 6 replies
    NASA ^ | September 26, 2013 | (see photo credit)
    Explanation: Separated by about 14 degrees (28 Full Moons) in planet Earth's sky, spiral galaxies M31, left, and M33 are both large members of the Local Group, along with our own Milky Way galaxy. This wide-angle, telescopic mosaic captures colorful details of spiral structure in both, while the massive neighboring galaxies seem to be balanced either side of bright Mirach, beta star in the constellation Andromeda. But M31, the Andromeda Galaxy, is really 2.5 million light-years distant and M33, the Triangulum Galaxy, is also about 3 million light years away. Mirach, just 200 light-years from the Sun, lies well within...
  • Astronomy Picture of the Day -- M81 versus M82

    09/25/2013 12:54:13 AM PDT · by SunkenCiv · 10 replies
    NASA ^ | September 25, 2013 | (see photo credit)
    Explanation: Here in the Milky Way galaxy we have astronomical front row seats as M81 and M82 face-off, a mere 12 million light-years away. Locked in a gravitational struggle for the past billion years or so, the two bright galaxies are captured in this deep telescopic snapshot, constructed from 25 hours of image data. Their most recent close encounter likely resulted in the enhanced spiral arms of M81 (left) and violent star forming regions in M82 so energetic the galaxy glows in X-rays. After repeated passes, in a few billion years only one galaxy will remain. From our perspective, this...
  • Astronomy Picture of the Day -- The Local Fluff

    09/24/2013 5:47:12 PM PDT · by SunkenCiv · 4 replies
    NASA ^ | September 24, 2013 | (see photo credit)
    Explanation: The stars are not alone. In the disk of our Milky Way Galaxy about 10 percent of visible matter is in the form of gas, called the interstellar medium (ISM). The ISM is not uniform, and shows patchiness even near our Sun. It can be quite difficult to detect the local ISM because it is so tenuous and emits so little light. This mostly hydrogen gas, however, absorbs some very specific colors that can be detected in the light of the nearest stars. A working map of the local ISM within 20 light-years, based on ongoing observations and recent...
  • Astronomy Picture of the Day -- IC 4628: The Prawn Nebula

    09/23/2013 3:42:42 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | September 23, 2013 | (see photo credit)
    Explanation: South of Antares, in the tail of the nebula-rich constellation Scorpius, lies emission nebula IC 4628. Nearby hot, massive stars, millions of years young, radiate the nebula with invisible ultraviolet light, stripping electrons from atoms. The electrons eventually recombine with the atoms to produce the visible nebular glow, dominated by the red emission of hydrogen. At an estimated distance of 6,000 light-years, the region shown is about 250 light-years across, spanning an area equivalent to four full moons on the sky. The nebula is also cataloged as Gum 56 for Australian astronomer Colin Stanley Gum, but seafood-loving astronomers might...
  • Astronomy Picture of the Day -- Apollo's Analemma

    09/21/2013 9:49:29 PM PDT · by SunkenCiv · 3 replies
    NASA ^ | September 22, 2013 | (see photo credit)
    Explanation: Today, the Sun crosses the celestial equator heading south at 20:44 Universal Time. An equinox (equal night), this astronomical event marks the first day of autumn in the northern hemisphere and spring in the south. With the Sun on the celestial equator, Earth dwellers will experience nearly 12 hours of daylight and 12 hours of darkness. To celebrate, consider this remarkable record of the Sun's yearly journey through planet Earth's sky, made with planned multiple exposures captured on a single piece of 35 millimeter film. Exposures were made at the same time of day (9:00am local time), capturing the...
  • Astronomy Picture of the Day -- Antares Rocket Launch

    09/21/2013 6:35:18 AM PDT · by SunkenCiv · 7 replies
    NASA ^ | September 21, 2013 | (see photo credit)
    Explanation: The sky looks dark in this scene from the Mid-Atlantic Regional Spaceport (MARS) at NASA Wallops Flight Facility, Virginia. Captured on Wednesday, September 18, an Orbital Sciences Corporation Antares rocket is leaving launch pad-0A with the Cygnus cargo spacecraft aboard. Though it looks like night, the photograph was taken at 10:58am EDT, under bright, clear morning skies, with a digital camera modified to record infrared images. The Sun itself is above and left of the picture frame, creating strong glare and internal reflections in the camera lens at near-infrared wavelengths. In the false-color presentation, the vegetation and watery reflections...
  • Astronomy Picture of the Day -- Night at the Drive-in

    09/21/2013 6:35:12 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | September 20, 2013 | (see photo credit)
    Explanation: Colorful stars trail through this late summer, night skyscape from Cape Cod, Massachusetts. The picture was composed by stacking 12 consecutive 1 minute long digital camera exposures to follow the trails, a reflection of our fair planet's daily rotation. It also records faint clouds of the Milky Way in the clear sky, stretching above a local drive-in movie theater. In fact, watching movies from cars at the drive-in was once a more common night time activity. But while the stars still shine, drive-in theaters have faded from the American landscape over the decades since the 1950s. Still, this recent...
  • Astronomy Picture of the Day -- Moon, Venus and Planet Earth

    09/19/2013 3:59:51 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | September 19, 2013 | (see photo credit)
    Explanation: In this engaging scene from planet Earth, the Moon shines through cloudy skies following sunset on the evening of September 8. Despite the fading light, the camera's long exposure still recorded a colorful, detailed view of a shoreline and western horizon looking toward the island San Gabriel from Colonia del Sacramento, Uruguay. Lights from Buenos Aires, Argentina are along the horizon on the left, across the broad Rio de la Plata estuary. The long exposure strongly overexposed the Moon and sky around it, though. So the photographer quickly snapped a shorter one to merge with the first image in...
  • Astronomy Picture of the Day -- M45: The Pleiades Star Cluster

    09/18/2013 7:05:11 PM PDT · by SunkenCiv · 9 replies
    NASA ^ | September 18, 2013 | (see photo credit)
    Explanation: Have you ever seen the Pleiades star cluster? Even if you have, you probably have never seen it as dusty as this. Perhaps the most famous star cluster on the sky, the bright stars of the Pleiades can be seen without binoculars from even the depths of a light-polluted city. With a long exposure from a dark location, though, the dust cloud surrounding the Pleiades star cluster becomes very evident. The above exposure took about 20 minutes and covers a sky area several times the size of the full moon. Also known as the Seven Sisters and M45, the...
  • Astronomy Picture of the Day -- Galaxy Cluster Abell 1689 Deflects Light

    09/17/2013 3:58:07 AM PDT · by SunkenCiv · 4 replies
    NASA ^ | September 17, 2013 | (see photo credit)
    Explanation: It is one of the most massive objects in the visible universe. In this view from the Hubble Space Telescope's Advanced Camera for Surveys, Abell 1689 is seen to warp space as predicted by Einstein's theory of gravity -- deflecting light from individual galaxies which lie behind the cluster to produce multiple, curved images. The power of this enormous gravitational lens depends on its mass, but the visible matter, in the form of the cluster's yellowish galaxies, only accounts for about one percent of the mass needed to make the observed bluish arcing images of background galaxies. In fact,...
  • Astronomy Picture of the Day -- Rotating Moon from LRO

    09/16/2013 6:05:02 PM PDT · by SunkenCiv · 12 replies
    NASA ^ | September 16, 2013 | (see photo credit)
    Explanation: No one, presently, sees the Moon rotate like this. That's because the Earth's moon is tidally locked to the Earth, showing us only one side. Given modern digital technology, however, combined with many detailed images returned by the Lunar Reconnaissance Orbiter (LRO), a high resolution virtual Moon rotation movie has now been composed. The above time-lapse video starts with the standard Earth view of the Moon. Quickly, though, Mare Orientale, a large crater with a dark center that is difficult to see from the Earth, rotates into view just below the equator. From an entire lunar month condensed into...
  • Astronomy Picture of the Day -- M2-9: Wings of a Butterfly Nebula

    09/14/2013 9:25:16 PM PDT · by SunkenCiv · 13 replies
    NASA ^ | September 15, 2013 | (see photo credit)
    Explanation: Are stars better appreciated for their art after they die? Actually, stars usually create their most artistic displays as they die. In the case of low-mass stars like our Sun and M2-9 pictured above, the stars transform themselves from normal stars to white dwarfs by casting off their outer gaseous envelopes. The expended gas frequently forms an impressive display called a planetary nebula that fades gradually over thousand of years. M2-9, a butterfly planetary nebula 2100 light-years away shown in representative colors, has wings that tell a strange but incomplete tale. In the center, two stars orbit inside a...
  • Astronomy Picture of the Day -- A Landing on Planet Earth

    09/14/2013 5:43:54 AM PDT · by SunkenCiv · 14 replies
    NASA ^ | September 14, 2013 | (see photo credit)
    Explanation: With parachute deployed and retro-rockets blazing, this spacecraft landed on planet Earth on September 11 (UT) in a remote area near the town of Zhezkazgan, Kazakhstan. Seen in silhouette against the rockets' glare, the spacecraft is a Soyuz TMA-08M. Its crew, Expedition 36 Commander Pavel Vinogradov and Flight Engineer Alexander Misurkin of the Russian Federal Space Agency (Roscosmos), and Flight Engineer Chris Cassidy of NASA were returning after five and half months aboard the International Space Station. The Soyuz retro-rockets fire very quickly and for an extremely short duration near touchdown. Capturing the moment, the well-timed photograph was taken...
  • Astronomy Picture of the Day -- Crescent Moon Meets Evening Star

    09/13/2013 5:39:53 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | September 13, 2013 | (see photo credit)
    Explanation: On September 8, brilliant planet Venus appearing as the evening star stood near a slender, crescent Moon at sunset. The close celestial pairing or conjunction was a scene enjoyed by skygazers around the world. But from some locations in South America, the Moon actually passed in front of Venus in a lunar occultation. Captured near Las Cañas, Uruguay, this two frame mosaic telescopic view shows the Moon and Venus before and after the occultation. The silvery evening star appears at right just before it winked out behind the dark lunar limb, still in bright twilight skies. About an hour...
  • Astronomy Picture of the Day -- Stars and Dust Across Corona Australis

    09/12/2013 6:06:33 AM PDT · by SunkenCiv · 6 replies
    NASA ^ | September 12, 2013 | (see photo credit)
    Explanation: Cosmic dust clouds sprawl across a rich field of stars in this sweeping telescopic vista near the northern boundary of Corona Australis, the Southern Crown. Less than 500 light-years away the dust clouds effectively block light from more distant background stars in the Milky Way. The entire frame spans about 2 degrees or over 15 light-years at the clouds' estimated distance. Near center is a group of lovely reflection nebulae cataloged as NGC 6726, 6727, 6729, and IC 4812. A characteristic blue color is produced as light from hot stars is reflected by the cosmic dust. The dust also...
  • Astronomy Picture of the Day -- LADEE Launch Streak

    09/11/2013 3:49:01 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | September 11, 2013 | (see photo credit)
    Explanation: On September 6, a starry night and the Milky Way witnessed the launch of a Minotaur V rocket from NASA's Wallops Flight Facility on Wallops Island, Virginia. So did a large part of the eastern United States, as the spectacular night launch was easily visible even from light polluted urban areas. This 35 second exposure captures part of the rocket's initial launch streak and 2nd stage ignition flare along with a brilliant reflection of the fiery sky in calm waters. The stunning view faces south and west from a vantage point overlooking Sinepuxent Bay in Maryland about 20 miles...
  • Astronomy Picture of the Day -- Extrasolar Super-Earth Gliese 1214b Might Hold Water

    09/10/2013 3:49:55 AM PDT · by SunkenCiv · 12 replies
    NASA ^ | September 10, 2013 | (see photo credit)
    Explanation: Might this distant planet hold water? Actually, given how close Gliese 1214b is to its parent star, any water, if it exists, would surely be in the form of steam. In the above artist's illustration, the super-Earth Gliese 1214b is imagined passing in front of its parent star, creating a mini-eclipse that alerted humanity to its presence. Gliese 1214b, also designated GJ 1214b, has been designated a super-Earth because it is larger than the Earth but smaller a planet like Neptune. The entire Gliese 1214 planetary system is of the closest known systems to our Sun, located only 42...
  • Astronomy Picture of the Day -- Nearby Cepheid Variable RS Pup

    09/09/2013 7:42:32 PM PDT · by SunkenCiv · 3 replies
    NASA ^ | September 09, 2013 | (see photo credit)
    Explanation: It is one of the most important stars in the sky. This is partly because, by coincidence, it is surrounded by a dazzling reflection nebula. Pulsating RS Puppis, the brightest star in the image center, is some ten times more massive than our Sun and on average 15,000 times more luminous. In fact, RS Pup is a Cepheid type variable star, a class of stars whose brightness is used to estimate distances to nearby galaxies as one of the first steps in establishing the cosmic distance scale. As RS Pup pulsates over a period of about 40 days, its...
  • Astronomy Picture of the Day -- Roll Cloud Over Wisconsin

    09/08/2013 11:59:58 AM PDT · by SunkenCiv · 20 replies
    NASA ^ | September 08, 2013 | (see photo credit)
    Explanation: What kind of cloud is this? A type of arcus cloud called a roll cloud. These rare long clouds may form near advancing cold fronts. In particular, a downdraft from an advancing storm front can cause moist warm air to rise, cool below its dew point, and so form a cloud. When this happens uniformly along an extended front, a roll cloud may form. Roll clouds may actually have air circulating along the long horizontal axis of the cloud. A roll cloud is not thought to be able to morph into a tornado. Unlike a similar shelf cloud, a...
  • Astronomy Picture of the Day -- Night in the Andes Ice Forest

    09/08/2013 11:58:50 AM PDT · by SunkenCiv · 12 replies
    NASA ^ | September 07, 2013 | (see photo credit)
    Explanation: This forest of snow and ice penitentes reflects moonlight shining across the Chajnantor plateau. The region lies in the Chilean Andes at an altitude of 5,000 meters, not far from one of planet Earth's major astronomical observatories, the Atacama Large Millimeter/submillimeter Array. Up to several meters high, the flattened, sharp-edged shapes, and orientation of the penitentes tend to minimize their shadows at local noon. In the dry, cold, thin atmosphere, sublimation driven by sunlight is important for their formation. A direct transition from a solid to a gaseous state, sublimation shapes other solar system terrains too, like icy surfaces...
  • Astronomy Picture of the Day -- The Quiet Sagittarius A*

    09/08/2013 11:57:55 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | September 06, 2013 | (see photo credit)
    Explanation: Hot gas is hard to swallow. At least that seems to be true for the supermassive black hole at the center of our Milky Way Galaxy. Known as source Sagittarius A*, the Milky Way's black hole is centered in this infrared (red and yellow hues) and X-ray (blue) composite. Based on data from an extensive campaign of observations by the orbiting Chandra X-ray telescope, the diffuse emission surrounding the black hole is seen in the close-up inset, the inset field spanning about 1/2 light-year across the galactic center some 26,000 light-years away. Astronomers have found that the X-ray emission...
  • Astronomy Picture of the Day -- M1: The Incredible Expanding Crab

    09/05/2013 7:37:34 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | September 05, 2013 | (see photo credit)
    Explanation: The Crab Nebula is cataloged as M1, the first on Charles Messier's famous list of things which are not comets. In fact, the Crab is now known to be a supernova remnant, an expanding cloud of debris from the explosion of a massive star. The violent birth of the Crab was witnessed by astronomers in the year 1054. Roughly 10 light-years across today, the nebula is still expanding at a rate of over 1,000 kilometers per second. Want to watch the Crab Nebula expand? Check out this video (vimeo) animation comparing an image of M1 taken in 1999 at...
  • Astronomy Picture of the Day -- IRAS 20324: Evaporating Protostar

    09/04/2013 4:04:22 PM PDT · by SunkenCiv · 12 replies
    NASA ^ | September 04, 2013 | (see photo credit)
    Explanation: Will this caterpillar-shaped interstellar cloud one day evolve into a butterfly-shaped nebula? No one is sure. What is sure is that IRAS 20324+4057, on the inside, is contracting to form a new star. On the outside, however, energetic winds are blowing and energetic light is eroding away much of the gas and dust that might have been used to form the star. Therefore, no one is sure what mass the resulting star will have, and, therefore, no one knows the fate of this star. Were the winds and light to whittle the protostar down near the mass of the...
  • Astronomy Picture of the Day -- North America and the Pelican

    09/03/2013 4:28:42 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | September 03, 2013 | (see photo credit)
    Explanation: Here lie familiar shapes in unfamiliar locations. On the left is an emission nebula cataloged as NGC 7000, famous partly because it resembles our fair planet's continent of North America. The emission region to the right of the North America Nebula is IC 5070, also known for its suggestive outlines as the Pelican Nebula. Separated by a dark cloud of obscuring dust, the two bright nebulae are about 1,500 light-years away. At that distance, the 4 degree wide field of view spans 100 light-years. This spectacular cosmic portrait combines narrow band images to highlight bright ionization fronts with fine...
  • Astronomy Picture of the Day -- Milky Way Over Spain's Bardenas Reales

    09/02/2013 12:33:43 PM PDT · by SunkenCiv · 15 replies
    NASA ^ | September 02, 2013 | (see photo credit)
    Explanation: What's that below the Milky Way? First, across the top of the above image, lies the faint band that is our planet's sideways view of the central disk of our home Milky Way Galaxy. The Milky Way band can be seen most clear nights from just about anywhere on Earth with a dark sky. What lies beneath is, by comparison, is a much less common sight. It is the striking peak of Castildetierra, a rock formation located in Bardenas Reales, a natural badlands in northeast Spain. Standing 50 meters tall, the rock spire includes clay and sandstone left over...
  • Astronomy Picture of the Day -- Fire on Earth [from year 2000]

    08/31/2013 9:14:15 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | September 01, 2013 | (see photo credit)
    Explanation: Sometimes, regions of planet Earth light up with fire. Since fire is the rapid acquisition of oxygen, and since oxygen is a key indicator of life, fire on any planet would be an indicator of life on that planet. Most of the Earth's land has been scorched by fire at some time in the past. Although causing many a tragedy, for many places on Earth fire is considered part of a natural ecosystem cycle. Large forest fires on Earth are usually caused by lightning and can be visible from orbit. Above, in the year 2000, stunned elk avoid a...
  • Astronomy Picture of the Day -- NGC 5195: The Dot Under the Question Mark

    08/31/2013 6:19:59 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | August 31, 2013 | (see photo credit)
    Explanation: Dwarf galaxy NGC 5195 is best known as the smaller companion of spiral M51, the Whirlpool galaxy. Seen together they seem to trace the curve and dot of a cosmic question mark, recorded in Lord Rosse's 19th century drawings as one of the original spiral nebulae. Dwarfed by enormous M51 (aka NGC 5194), NGC 5195 spans about 20,000 light-years. A close encounter with M51 has likely triggered star formation and enhanced that galaxy's prominent spiral arms. Processed from image data available in the Hubble Legacy Archive, this majestic close-up of NGC 5195 makes it clear that the dwarf galaxy...
  • Astronomy Picture of the Day -- A Sagittarius Triplet

    08/30/2013 7:49:25 PM PDT · by SunkenCiv · 2 replies
    NASA ^ | August 30, 2013 | (see photo credit)
    Explanation: These three bright nebulae are often featured in telescopic tours of the constellation Sagittarius and the crowded starfields of the central Milky Way. In fact, 18th century cosmic tourist Charles Messier cataloged two of them; M8, the large nebula left of center, and colorful M20 on the right. The third, NGC 6559, is above M8, separated from the larger nebula by a dark dust lane. All three are stellar nurseries about five thousand light-years or so distant. The expansive M8, over a hundred light-years across, is also known as the Lagoon Nebula. M20's popular moniker is the Trifid. Glowing...
  • Astronomy Picture of the Day -- Strawberry Sun

    08/29/2013 3:58:38 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | August 29, 2013 | (see photo credit)
    Explanation: This striking, otherworldy scene really is a view from planet Earth. The ochre sky and strawberry red sun were photographed on August 22nd near the small village of Strawberry, California, USA. Found along Highway 108, that location is about 30 miles north of the origin of California's large Rim Fire, still threatening areas in and around Yosemite National Park. The extensive smoke plumes from the wildfire are easily visible from space. But seen from within the plumes, the fine smoke particles suspended in the atmosphere dim the Sun, scattering blue light and strongly coloring the sky.
  • Astronomy Picture of the Day -- A Retreating Thunderstorm at Sunset

    08/28/2013 3:43:38 AM PDT · by SunkenCiv · 9 replies
    NASA ^ | August 28, 2013 | (see photo credit)
    Explanation: What type of cloud is that? This retreating cumulonimbus cloud, more commonly called a thundercloud, is somewhat unusual as it contains the unusual bumpiness of a mammatus cloud on the near end, while simultaneously producing falling rain on the far end. Taken in mid-June in southern Alberta, Canada, the cloud is moving to the east, into the distance, as the sun sets in the west, behind the camera. In the above image, graphic sunset colors cross the sky to give the already photogenic cloud striking orange and pink hues. A darkening blue sky covers the background. Further in the...
  • Astronomy Picture of the Day -- A Flight through the Hubble Ultra Deep Field

    08/27/2013 3:54:48 AM PDT · by SunkenCiv · 6 replies
    NASA ^ | August 27, 2013 | (see photo credit)
    Explanation: What would it look like to fly through the distant universe? To find out, a team of astronomers estimated the relative distances to over 5,000 galaxies in one of the most distant fields of galaxies ever imaged: the Hubble Ultra Deep Field (HUDF). Because it takes light a long time to cross the universe, most galaxies visible in the above video are seen when the universe was only a fraction of its current age, were still forming, and have unusual shapes when compared to modern galaxies. No mature looking spiral galaxies such as our Milky Way or the Andromeda...