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Astronomy Picture of the Day (General/Chat)

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  • Astronomy Picture of the Day -- The ISS and a Colorful Moon

    07/31/2015 4:18:26 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | July 31, 2015 | (see photo credit)
    Explanation: Tonight's Full Moon, the second Full Moon in July, could be called a blue moon according to modern folklore. But this sharp and detailed mosaic, recorded with telescope and digital camera just before July's first Full Moon, actually does show a colorful lunar surface. The colors have been enhanced in the processed image but are real nonetheless, corresponding to real differences in the chemical makeup of the lunar surface. Also easy to see especially when the Moon is near full phase, bright rays from 85 kilometer wide Tycho crater at the upper right extend far across the lunar surface....
  • Astronomy Picture of the Day -- Milky Way over Uluru

    07/30/2015 1:16:33 AM PDT · by SunkenCiv · 6 replies
    NASA ^ | July 30, 2015 | (see photo credit)
    Explanation: The central regions of our Milky Way Galaxy rise above Uluru/Ayers Rock in this striking night skyscape. Recorded on July 13, a faint airglow along the horizon shows off central Australia's most recognizable landform in silhouette. Of course the Milky Way's own cosmic dust clouds appear in silhouette too, dark rifts along the galaxy's faint congeries of stars. Above the central bulge, rivers of cosmic dust converge on a bright yellowish supergiant star Antares. Left of Antares, wandering Saturn shines in the night.
  • Astronomy Picture of the Day -- The Deep Lagoon

    07/29/2015 4:09:07 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | July 29, 2015 | (see photo credit)
    Explanation: Ridges of glowing interstellar gas and dark dust clouds inhabit the turbulent, cosmic depths of the Lagoon Nebula. Also known as M8, The bright star forming region is about 5,000 light-years distant. But it still makes for a popular stop on telescopic tours of the constellation Sagittarius, toward the center of our Milky Way Galaxy. Dominated by the telltale red emission of ionized hydrogen atoms recombining with stripped electrons, this stunning, deep view of the Lagoon's central reaches is about 40 light-years across. Near the center of the frame, the bright hourglass shape is gas ionized and sculpted by...
  • Astronomy Picture of the Day -- Rainbows and Rays over Bryce Canyon

    07/28/2015 5:55:29 PM PDT · by SunkenCiv · 6 replies
    NASA ^ | July 28, 2015 | (see photo credit)
    Explanation: What's happening over Bryce Canyon? Two different optical effects that were captured in one image taken earlier this month. Both effects needed to have the Sun situated directly behind the photographer. The nearest apparition was the common rainbow, created by sunlight streaming from the setting sun over the head of the photographer, and scattering from raindrops in front of the canyon. If you look closely, even a second rainbow appears above the first. More rare, and perhaps more striking, are the rays of light that emanate out from the horizon above the canyon. These are known as anticrepuscular rays...
  • Astronomy Picture of the Day - Milky Way and Aurora over Antarctica

    07/26/2015 9:41:25 PM PDT · by SunkenCiv · 19 replies
    NASA ^ | July 27, 2015 | Image Credit & Copyright: LI Hang
    Explanation: It has been one of the better skies of this long night. In parts of Antarctica, not only is it winter, but the Sun can spend weeks below the horizon. At China's Zhongshan Station, people sometimes venture out into the cold to photograph a spectacular night sky. The featured image from one such outing was taken in mid-July, just before the end of this polar night. Pointing up, the wide angle lens captured not only the ground at the bottom, but at the top as well. In the foreground is a colleague also taking pictures. In the distance, a...
  • Astronomy Picture of the Day -- The Sombrero Galaxy from Hubble

    07/26/2015 8:36:07 AM PDT · by SunkenCiv · 18 replies
    NASA ^ | July 26, 2015 | (see photo credit)
    Explanation: Why does the Sombrero Galaxy look like a hat? Reasons include the Sombrero's unusually large and extended central bulge of stars, and dark prominent dust lanes that appear in a disk that we see nearly edge-on. Billions of old stars cause the diffuse glow of the extended central bulge. Close inspection of the bulge in the above photograph shows many points of light that are actually globular clusters. M104's spectacular dust rings harbor many younger and brighter stars, and show intricate details astronomers don't yet fully understand. The very center of the Sombrero glows across the electromagnetic spectrum, and...
  • Astronomy Picture of the Day -- Infrared Trifid

    07/25/2015 1:58:13 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | July 25, 2015 | (see photo credit)
    Explanation: The Trifid Nebula, also known as Messier 20, is easy to find with a small telescope, a well known stop in the nebula rich constellation Sagittarius. But where visible light pictures show the nebula divided into three parts by dark, obscuring dust lanes, this penetrating infrared image reveals filaments of glowing dust clouds and newborn stars. The spectacular false-color view is courtesy of the Spitzer Space Telescope. Astronomers have used the Spitzer infrared image data to count newborn and embryonic stars which otherwise can lie hidden in the natal dust and gas clouds of this intriguing stellar nursery. As...
  • Astronomy Picture of the Day -- Ultraviolet Rings of M31

    07/24/2015 5:01:17 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | July 24, 2015 | (see photo credit)
    Explanation: A mere 2.5 million light-years away the Andromeda Galaxy, also known as M31, really is just next door as large galaxies go. So close and spanning some 260,000 light-years, it took 11 different image fields from the Galaxy Evolution Explorer (GALEX) satellite's telescope to produce this gorgeous portrait of the spiral galaxy in ultraviolet light. While its spiral arms stand out in visible light images of Andromeda, the arms look more like rings in the GALEX ultraviolet view, a view dominated by the energetic light from hot, young, massive stars. As sites of intense star formation, the rings have...
  • Astronomy Picture of the Day -- Comet PanSTARRS, Moon, and Venus

    07/23/2015 3:41:01 AM PDT · by SunkenCiv · 4 replies
    NASA ^ | July 23, 2015 | (see photo credit)
    Explanation: It is the object to the left of the big tree that's generating much recent excitement. If you look closely, there you can see Comet PanSTARRS, complete with two tails. During July, this comet has increased markedly in brightness and has just passed its closest approach to Earth. The statuesque tree in the center is a Norfolk Island Pine, and to either side of this tree are New Zealand Pohutukaw trees. Over the trees, far in the distance, are bright Venus and an even brighter crescent Moon. If you look even more closely, you can find Jupiter hidden in...
  • Astronomy Picture of the Day -- Gamma-ray Rain from 3C 279

    07/22/2015 4:28:31 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | July 22, 2015 | (see photo credit)
    Explanation: If gamma-rays were raindrops a flare from a supermassive black hole might look like this. Not so gently falling on the Fermi Gamma-ray Space Telescope from June 14 to June 16 the gamma-ray photons, with energies up to 50 billion electron volts, originated in active galaxy 3C 279 some 5 billion light-years away. Each gamma-ray "drop" is an expanding circle in the timelapse visualization, the color and maximum size determined by the gamma-ray's measured energy. Starting with a background drizzle, the sudden downpour that then trails off is the intense, high energy flare. The creative and calming presentation of...
  • Astronomy Picture of the Day -- Comet Tails and Star Trails

    07/21/2015 9:22:38 AM PDT · by SunkenCiv · 7 replies
    NASA ^ | July 21, 2015 | (see photo credit)
    Explanation: After grazing the western horizon on northern summer evenings Comet PanSTARRS (also known as C/2014 Q1) climbed higher in southern winter skies. A visitor to the inner Solar System discovered in August 2014 by the prolific panSTARRS survey, the comet was captured here on July 17. Comet and colorful tails were imaged from Home Observatory in Mackay, Queensland, Australia. The field of view spans just over 1 degree. Sweeping quickly across a the sky this comet PanSTARRS was closest to planet Earth about 2 days later. Still, the faint stars of the constellation Cancer left short trails in the...
  • Astronomy Picture of the Day -- Comet PanSTARRS and a Crescent Moon

    07/20/2015 7:06:04 AM PDT · by SunkenCiv · 4 replies
    NASA ^ | July 20, 2015 | (see photo credit)
    Explanation: A comet has brightened quickly and unexpectedly. Discovered last year, Comet C/2014 Q1 (PanSTARRS) is expected to be visible now for a few days to the unaided eye, just after sunset, from some locations. The comet rounded the Sun on July 6 and apparently has shed quite a bit of gas and dust. Today it is now as close as it will ever get to the Earth, which is another factor in its recent great apparent brightness and the large angular extent of its tails. In the featured image taken two days ago, Comet PanSTARRS is seen sporting a...
  • Astronomy Picture of the Day -- The First Rocket Launch from Cape Canaveral

    07/19/2015 12:59:44 PM PDT · by SunkenCiv · 13 replies
    NASA ^ | July 19, 2015 | (see photo credit)
    Explanation: A new chapter in space flight began this week in 1950 July with the launch of the first rocket from Cape Canaveral, Florida: the Bumper V-2. Shown above, the Bumper V-2 was an ambitious two-stage rocket program that topped a V-2 missile base with a WAC Corporal rocket. The upper stage was able to reach then-record altitudes of almost 400 kilometers, higher than even Space Shuttles once flew. Launched under the direction of the General Electric Company, the Bumper V-2 was used primarily for testing rocket systems and for research on the upper atmosphere. Bumper V-2 rockets carried small...
  • Astronomy Picture of the Day -- Fly Over Pluto

    07/18/2015 2:44:26 PM PDT · by SunkenCiv · 35 replies
    NASA ^ | July 18, 2015 | (see photo credit)
    Explanation: It took 9.5 years to get this close, but you can now take a virtual flight over Pluto in this animation of image data from the New Horizons spacecraft. The Plutonian terrain unfolding 48,000 miles (77,000 kilometers) below is identified as Norgay Montes, followed by Sputnik Planum. The icy mountains, informally named for one of the first two Mount Everest climbers Tenzing Norgay, reach up to 11,000 feet (3,500 meters) above the surface. The frozen, young, craterless plains are informally named for the Earth's first artificial satellite. Sputnik Planum is north of Norgay Montes, within Pluto's expansive, bright, heart-shaped...
  • Astronomy Picture of the Day -- Charon

    07/16/2015 9:30:06 PM PDT · by SunkenCiv · 24 replies
    NASA ^ | July 17, 2015 | (see photo credit)
    Explanation: Icy world Charon is 1,200 kilometers across. That makes Pluto's largest moon only about 1/10th the size of planet Earth but a whopping 1/2 the diameter of Pluto itself. Charon is seen in unprecedented detail in this image from New Horizons. The image was captured late July 13 during the spacecraft's flight through the Plutonian system from a range of less than 500,000 kilometers. For reference, the distance separating Earth and Moon is less than 400,000 kilometers. Charonian terrain, described as surprising, youthful, and varied, includes a 1,000 kilometer swath of cliffs and troughs stretching below center, a 7...
  • Astronomy Picture of the Day -- 50 Miles on Pluto

    07/16/2015 1:20:07 PM PDT · by SunkenCiv · 20 replies
    NASA ^ | July 16, 2015 | (see photo credit)
    Explanation: A 50 mile (80 kilometer) trip across Pluto would cover the distance indicated by the scale bar in this startling image. The close-up of the icy world's rugged equatorial terrain was captured when the New Horizons spacecraft was about 47,800 miles (77,000 kilometers) from the surface, 1.5 hours before its closest approach. Rising to an estimated 11,000 feet (3,500 meters) the mountains are likely composed of water ice. Suggesting surprising geological activity, they are also likely young with an estimated age of 100 million years or so based on the apparent absence of craters. The region pictured is near...
  • Astronomy Picture of the Day -- Pluto Resolved

    07/14/2015 10:44:26 PM PDT · by SunkenCiv · 29 replies
    NASA ^ | July 15, 2015 | (see photo credit)
    Explanation: New Horizons has survived its close encounter with Pluto and has resumed sending back images and data. The robotic spacecraft reported back on time, with all systems working, and with the expected volume of data stored. Featured here is the highest resolution image of Pluto taken before closest approach, an image that really brings Pluto into a satisfying focus. At first glance, Pluto is reddish and has several craters. Toward the image bottom is a surprisingly featureless light-covered region that resembles an iconic heart, and mountainous terrain appears on the lower right. This image, however, is only the beginning....
  • Astronomy Picture of the Day -- Last Look at Pluto's Charon Side

    07/12/2015 10:15:14 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | July 13, 2015 | (see photo credit)
    Explanation: Pluto surface is strange. As the robotic New Horizons barrels toward its closest approach to Pluto and its moons tomorrow, images already coming back show Pluto's surface to be curiouser and curiouser. The featured image, taken two days ago, shows the side of Pluto that always faces Pluto's largest moon Charon. Particularly noteworthy is the dark belt near the bottom that circles Pluto's equator. It is currently unclear whether regions in this dark belt are mountainous or flat, why boundaries are so sharply defined, and why the light regions seem to be nearly evenly spaced. As New Horizons will...
  • Astronomy Picture of the Day -- New Horizons Launch to Pluto

    07/12/2015 10:12:53 PM PDT · by SunkenCiv · 3 replies
    NASA ^ | July 12, 2015 | (see photo credit)
    Explanation: Destination: Pluto. The New Horizons spacecraft roared off its launch pad at Cape Canaveral in Florida, USA in 2006 toward adventures in the distant Solar System. The craft is the fastest spaceships ever launched by humans, having passed the Moon only nine hours after launch, and Jupiter only a year later. After spending almost a decade crossing the Solar System, New Horizons will fly past Pluto on Tuesday. Pluto, officially a planet when New Horizons launched, has never been visited by a spacecraft or photographed up close. After Pluto, the robot spaceship will visit one or more Kuiper Belt...
  • Astronomy Picture of the Day -- Geology on Pluto

    07/11/2015 4:52:38 AM PDT · by SunkenCiv · 18 replies
    NASA ^ | July 11, 2015 | (see photo credit)
    Explanation: Pluto is coming into focus. As the robotic New Horizons spacecraft bears down on this unexplored world of the distant Solar System, new features on its surface are becoming evident. In the displayed image taken last Thursday and released yesterday, an unusual polygonal structure roughly 200 kilometers wide is visible on the left, while just below it relatively complex terrain runs diagonally across the dwarf planet. New Horizon's images and data on these structures will likely be studied for years to come in an effort to better understand the geologic history of Pluto and our Solar System. After suffering...
  • Astronomy Picture of the Day -- Messier 43

    07/10/2015 1:15:47 PM PDT · by SunkenCiv · 8 replies
    NASA ^ | July 10, 2015 | (see photo credit)
    Explanation: Often imaged but rarely mentioned, Messier 43 is a large star forming region in its own right. It's just part of the star forming complex of gas and dust that includes the larger, more famous neighboring Messier 42, the Great Orion Nebula. In fact, the Great Orion Nebula itself lies off the lower edge of this scene. The close-up of Messier 43 was made while testing the capabilities of a near-infrared instrument with one of the twin 6.5 meter Magellan telescopes at Las Campanas Observatory in the Chilean Andes. The composite image shifts the otherwise invisible infrared wavelengths to...
  • Astronomy Picture of the Day -- 5 Million Miles from Pluto

    07/09/2015 4:54:42 AM PDT · by SunkenCiv · 22 replies
    NASA ^ | July 09, 2015 | (see photo credit)
    Explanation: An image snapped on July 7 by the New Horizons spacecraft while just under 5 million miles (8 million kilometers) from Pluto is combined with color data in this most detailed view yet of the Solar System's most famous world about to be explored. The region imaged includes the tip of an elongated dark area along Pluto's equator already dubbed "the whale". A bright heart-shaped region on the right is about 1,200 miles (2,000) kilometers across, possibly covered with a frost of frozen methane, nitrogen, and/or carbon monoxide. The view is centered near the area that will be seen...
  • Astronomy Picture of the Day -- In the Company of Dione

    07/08/2015 3:46:00 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | July 08, 2015 | (see photo credit)
    Explanation: That is not our Moon. It's Dione, and it's a moon of Saturn. The robotic Cassini spacecraft took the featured image during a flyby of Saturn's cratered Moon last month. Perhaps what makes this image so interesting, though, is the background. First, the large orb looming behind Dione is Saturn itself, faintly lit by sunlight first reflected from the rings. Next, the thin lines running diagonally across the image are the rings of Saturn themselves. The millions of icy rocks that compose Saturn's spectacular rings all orbit Saturn in the same plane, and so appear surprisingly thin when seen...
  • Astronomy Picture of the Day -- The Milky Way from a Malibu Sea Cave

    07/07/2015 4:23:55 AM PDT · by SunkenCiv · 14 replies
    NASA ^ | July 07, 2015 | (see photo credit)
    Explanation: What’s happening outside this cave? Nothing unexpected – it’s just the central band of our Milky Way Galaxy passing by. As the Earth turns, the band of our Galaxy appears to rotate and shift along the horizon. The featured image was taken by a photographer who professes a passion for locating sea caves, and who found this spectacular grotto in Leo Carrillo State Park near Malibu, California, USA. After some planning, he timed this single shot image through the 10-meter high cave entrance to show the Milky Way far in the distance. In the foreground, several rocks about one...
  • Astronomy Picture of the Day -- Colorful Clouds Near Rho Ophiuchi

    07/05/2015 10:53:32 PM PDT · by SunkenCiv · 1 replies
    NASA ^ | July 06, 2015 | (see photo credit)
    Explanation: Why is the sky near Antares and Rho Ophiuchi so colorful? The colors result from a mixture of objects and processes. Fine dust illuminated from the front by starlight produces blue reflection nebulae. Gaseous clouds whose atoms are excited by ultraviolet starlight produce reddish emission nebulae. Backlit dust clouds block starlight and so appear dark. Antares, a red supergiant and one of the brighter stars in the night sky, lights up the yellow-red clouds on the lower center of the featured image. Rho Ophiuchi lies at the center of the blue nebula on the left. The distant globular cluster...
  • Astronomy Picture of the Day -- Zeta Oph: Runaway Star

    07/05/2015 1:13:36 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | July 05, 2015 | (see photo credit)
    Explanation:
  • Astronomy Picture of the Day -- Aurora Australis

    07/04/2015 5:20:45 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | July 04, 2015 | (see photo credit)
    Explanation: Not fireworks, these intense shimmering lights still danced across Earth's night skies late last month, seen here above the planet's geographic south pole. The stunning auroral displays were triggered as a coronal mass ejection blasted from the Sun days earlier impacted the magnetosphere, beginning a widespread geomagnetic storm. The six fisheye panels were recorded with digital camera and battery in a heated box to guard against -90 degree F ambient temperatures of the long winter night. Around the horizon are south pole astronomical observatories, while beyond the Aurora Australis stretch the stars of the southern Milky Way.
  • Astronomy Picture of the Day -- Venus and Jupiter are Far

    07/03/2015 7:40:22 AM PDT · by SunkenCiv · 16 replies
    NASA ^ | July 03, 2015 | (see photo credit)
    Explanation: On June 30 Venus and Jupiter were actually far apart, but both appeared close in western skies at dusk. Near the culmination of this year's gorgeous conjunction, the two bright evening planets are captured in the same telescopic field of view in this sharp digital stack of images taken after sunset from Poznań in west-central Poland. In fact, banded gas giant Jupiter was about 910 million kilometers from Poland. That's over 11 times farther than crescent Venus, only 78 million kilometers distant at the time. But since the diameter of giant planet Jupiter is over 11 times larger than...
  • Astronomy Picture of the Day -- Venus and Jupiter are Close

    07/02/2015 11:17:19 AM PDT · by SunkenCiv · 18 replies
    NASA ^ | July 02, 2015 | (see photo credit)
    Explanation: On June 30, Venus and Jupiter were close in western skies at dusk. Near the culmination of this year's gorgeous conjunction, the two bright evening planets are captured in the same telescopic field of view in this image taken after sunset from Bejing, China. As the two bright planets set together in the west, a nearly Full Moon rose above the horizon to the south and east. Imaged that night with the same telescope and camera, the rising Moon from the opposite part of the sky is compared with the planetary conjunction for scale in the digitally composited image....
  • Astronomy Picture of the Day -- Venus, Jupiter, and Noctilucent Clouds

    07/01/2015 3:18:08 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | July 01, 2015 | (see photo credit)
    Explanation: Have you seen the passing planets yet? Today the planets Jupiter and Venus pass within half a degree of each other as seen from Earth. This conjunction, visible all over the world, is quite easy to see -- just look to the west shortly after sunset. The brightest objects visible above the horizon will be Venus and Jupiter, with Venus being the brighter of the two. Featured above, the closing planets were captured two nights ago in a sunset sky graced also by high-level noctilucent clouds. In the foreground, the astrophotographer's sister takes in the vista from a bank...
  • Astronomy Picture of the Day -- An Unusual Mountain on Asteroid Ceres

    06/29/2015 9:49:58 PM PDT · by SunkenCiv · 18 replies
    NASA ^ | June 30, 2015 | (see photo credit)
    Explanation: What created this large mountain on asteroid Ceres? No one is yet sure. As if in anticipation of today being Asteroid Day on Earth, the robotic spacecraft Dawn in orbit around Ceres took the best yet image of an unusually tall mountain on the Asteroid Belt's largest asteroid. Visible at the top of the featured image, the exceptional mountain rises about five kilometers up from an area that otherwise appears pretty level. The image was taken about two weeks ago from about 4,400 kilometers away. Although origin hypotheses for the mountain include volcanism, impacts, and plate tectonics, clear evidence...
  • Astronomy Picture of the Day -- Sunspot Group AR 2339 Crosses the Sun

    06/29/2015 7:18:10 AM PDT · by SunkenCiv · 6 replies
    NASA ^ | June 29, 2015 | (see photo credit)
    Explanation: How do sunspots evolve? Large dark sunspots -- and the active regions that contain them -- may last for weeks, but all during that time they are constantly changing. Such variations were particularly apparent a few weeks ago as the active region AR 2339 came around the limb of the Sun and was tracked for the next 12 days by NASA's Solar Dynamic Observatory. In the featured time lapse video, some sunspots drift apart, while others merge. All the while, the dark central umbral regions shift internally and their surrounding lighter penumbras shimmer and wave. The surrounding Sun appears...
  • Astronomy Picture of the Day -- All the Colors of the Sun

    06/27/2015 9:16:14 PM PDT · by SunkenCiv · 20 replies
    NASA ^ | June 28, 2015 | (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 -- Stars of a Summer's Triangle

    06/27/2015 3:42:59 PM PDT · by SunkenCiv · 13 replies
    NASA ^ | June 27, 2015 | (see photo credit)
    Explanation: Rising at the start of a northern summer's night, these three bright stars form the familiar asterism known as the Summer Triangle. Altair, Deneb, and Vega are the alpha stars of their respective constellations, Aquila, Cygnus, and Lyra, nestled near the Milky Way. Close in apparent brightness the three do look similar in these telescopic portraits, but all have their own stellar stories. Their similar appearance hides the fact that the Summer Triangle stars actually span a large range in intrinsic luminosity and distance. A main sequence dwarf star, Altair is some 10 times brighter than the Sun and...
  • Astronomy Picture of the Day -- Planet Aurora

    06/26/2015 1:21:43 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | June 26, 2015 | (see photo credit)
    Explanation: What bizarre alien planet is this ? It's planet Earth of course, seen through the shimmering glow of aurorae from the International Space Station. About 400 kilometers (250 miles) above, the orbiting station is itself within the upper realm of the auroral displays, also watched from the planet's surface on June 23rd. Aurorae have the signature colors of excited molecules and atoms at the low densities found at extreme altitudes. The eerie greenish glow of molecular oxygen dominates this view. But higher, just above the space station's horizon, is a rarer red band of aurora from atomic oxygen. The...
  • Astronomy Picture of the Day -- Star Trails above Table Mountain

    06/26/2015 1:21:40 PM PDT · by SunkenCiv · 8 replies
    NASA ^ | June 25, 2015 | (see photo credit)
    Explanation: Stars trail above and urban lights sprawl below in this moonlit nightscape from Cape Town, South Africa, planet Earth. The looming form of Table Mountain almost seems to hold terrestrial lights at bay while the stars circle the planet's South Celestial Pole. This modern perspective on the natural night sky was captured in June 2014, the scene composed of over nine hundred, stacked 30 second exposures. The stunning result was chosen as the winner in the Against the Lights category, a selection from over 800 entries in The World at Night's 2015 International Earth and Sky Photo Contest.
  • Astronomy Picture of the Day -- Triple Conjunction Over Galician National Park

    06/24/2015 4:04:07 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | June 24, 2015 | (see photo credit)
    Explanation: What are those bright objects hovering over the horizon? Planets -- and the Moon. First out, the horizon featured is a shoreline of the Atlantic Ocean that occurs at the Galicia National Park in northern Spain. Next furthest out, on the left, is the Moon. Easily the brightest object on the night sky, the Moon here was in only a crescent phase. The next furthest out, on the right, is the planet Venus, while planet Jupiter is seen at the top of the triangle. The long exposure from our rapidly rotating Earth made all of celestial objects -- including...
  • Astronomy Picture of the Day -- Sharpless 308: Star Bubble

    06/23/2015 4:14:40 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | June 23, 2015 | (see photo credit)
    Explanation: Blown by fast winds from a hot, massive star, this cosmic bubble is huge. Cataloged as Sharpless 2-308 it lies some 5,200 light-years away toward the constellation of the Big Dog (Canis Major) and covers slightly more of the sky than a Full Moon. That corresponds to a diameter of 60 light-years at its estimated distance. The massive star that created the bubble, a Wolf-Rayet star, is the bright one near the center of the nebula. Wolf-Rayet stars have over 20 times the mass of the Sun and are thought to be in a brief, pre-supernova phase of massive...
  • Astronomy Picture of the Day -- New Horizons [Pluto probe]

    06/21/2015 10:04:05 PM PDT · by SunkenCiv · 3 replies
    NASA ^ | June 22, 2015 | (see photo credit)
    Explanation: In three weeks, the robotic New Horizons spacecraft will reach Pluto. As the featured video makes clear, though, humanity has been on an unprecedented epoch of robotic exploration of our Solar System's planets for the past half century. The video highlights artistic illustrations of Mariner 2 flying by Venus in 1962, Mariner 4 flying past Mars in 1965, Pioneer 10 flying past Jupiter in 1973, Mariner 10 flying past Mercury in 1974, Pioneer 11 flying past Saturn in 1979, and Voyager 2 flying past Uranus in 1986 and then Neptune in 1989. Next is a hypothetical sequence depicting New...
  • Astronomy Picture of the Day -- Rings and Seasons of Saturn

    06/21/2015 7:10:57 AM PDT · by SunkenCiv · 15 replies
    NASA ^ | June 21, 2015 | (see photo credit)
    Explanation: On Saturn, the rings tell you the season. On Earth, today marks a solstice, the time when the Earth's spin axis tilts directly toward the Sun. On Earth's northern hemisphere, today is the Summer Solstice, the day of maximum daylight. Since Saturn's grand rings orbit along the planet's equator, these rings appear most prominent -- from the direction of the Sun -- when the Saturn's spin axis points toward the Sun. Conversely, when Saturn's spin axis points to the side, an equinox occurs and the edge-on rings are hard to see. In the featured montage, images of Saturn over...
  • Astronomy Picture of the Day -- Hubble's Messier 5 [whoa!]

    06/19/2015 11:33:10 PM PDT · by SunkenCiv · 27 replies
    NASA ^ | June 20, 2015 | (see photo credit)
    Explanation: "Beautiful Nebula discovered between the Balance [Libra] & the Serpent [Serpens] ..." begins the description of the 5th entry in 18th century astronomer Charles Messier's famous catalog of nebulae and star clusters. Though it appeared to Messier to be fuzzy and round and without stars, Messier 5 (M5) is now known to be a globular star cluster, 100,000 stars or more, bound by gravity and packed into a region around 165 light-years in diameter. It lies some 25,000 light-years away. Roaming the halo of our galaxy, globular star clusters are ancient members of the Milky Way. M5 is one...
  • Astronomy Picture of the Day -- LightSail A

    06/19/2015 5:31:30 PM PDT · by SunkenCiv · 3 replies
    NASA ^ | June 19, 2015 | (see photo credit)
    Explanation: Hitching a ride to low Earth orbit, LightSail A accomplished a challenging test mission, unfurling its 32 square meter mylar solar sail on June 7. This dramatic image from one of the bread loaf sized spacecraft's fisheye cameras captures the deployed sail glinting in sunlight. Sail out and visible to Earthbound observers before its final orbit, LightSail A reentered the atmosphere last weekend. Its succesful technology demonstration paves the way for the LightSail B spacecraft, scheduled for launch in April 2016. Once considered the stuff of science fiction, sailing through space was suggested 400 years ago by astronomer Johannes...
  • Astronomy Picture of the Day -- M64: The Black Eye Galaxy

    06/18/2015 4:26:59 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | June 18, 2015 | (see photo credit)
    Explanation: This big, bright, beautiful spiral galaxy is Messier 64, often called the Black Eye Galaxy or the Sleeping Beauty Galaxy for its heavy-lidded appearance in telescopic views. M64 is about 17 million light-years distant in the otherwise well-groomed northern constellation Coma Berenices. In fact, the Red Eye Galaxy might also be an appropriate moniker in this colorful composition. The enormous dust clouds obscuring the near-side of M64's central region are laced with the telltale reddish glow of hydrogen associated with star forming regions. But they are not this galaxy's only peculiar feature. Observations show that M64 is actually composed...
  • Astronomy Picture of the Day -- M45: The Pleiades Star Cluster

    06/17/2015 11:11:55 AM PDT · by SunkenCiv · 23 replies
    NASA ^ | June 17, 2015 | (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 featured exposure took over 12 hours 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 -- APOD is 20 Years Old Today

    06/16/2015 9:25:10 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | June 16, 2015 | (see photo credit)
    Explanation: Welcome to the vicennial year of the Astronomy Picture of the Day! Perhaps a source of web consistency for some, APOD is still here. As during each of the 20 years of selecting images, writing text, and editing the APOD web pages, the occasionally industrious Robert Nemiroff (left) and frequently persistent Jerry Bonnell (right) are pictured above plotting to highlight yet another unsuspecting image of our cosmos. Although the featured image may appear similar to the whimsical Vermeer composite that ran on APOD's fifth anniversary, a perceptive eye might catch that it has been digitally re-pixelated using many of...
  • Astronomy Picture of the Day -- A Colorful Lunar Corona

    06/15/2015 4:21:04 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | June 15, 2015 | (see photo credit)
    Explanation: What are those colorful rings around the Moon? A corona. Rings like this will sometimes appear when the Moon is seen through thin clouds. The effect is created by the quantum mechanical diffraction of light around individual, similarly-sized water droplets in an intervening but mostly-transparent cloud. Since light of different colors has different wavelengths, each color diffracts differently. Lunar Coronae are one of the few quantum mechanical color effects that can be easily seen with the unaided eye. The featured lunar corona was captured around a Strawberry Moon on June 2 from La Plata, Argentina. Similar coronae that form...
  • Astronomy Picture of the Day -- M101: The Pinwheel Galaxy

    06/15/2015 4:20:11 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | June 14, 2015 | (see photo credit)
    Explanation: Why do many galaxies appear as spirals? A striking example is M101, shown above, whose relatively close distance of about 27 million light years allows it to be studied in some detail. Observational evidence indicates that a close gravitational interaction with a neighboring galaxy created waves of high mass and condensed gas which continue to orbit the galaxy center. These waves compress existing gas and cause star formation. One result is that M101, also called the Pinwheel Galaxy, has several extremely bright star-forming regions (called HII regions) spread across its spiral arms. M101 is so large that its immense...
  • Astronomy Picture of the Day -- 1000 Sols

    06/15/2015 4:18:08 PM PDT · by SunkenCiv · 6 replies
    NASA ^ | June 13, 2015 | (see photo credit)
    Explanation: Shortly before Mars' June 2015 conjunction, the Curiosity Rover celebrated 1000 sols on the red planet. After its August 5, 2012 landing, Curiosity's 1000th sol or martian day on the surface corresponded to planet Earth's calendar date May 31, 2015. Because the line-of-sight to Mars is close to the Sun near the conjunction, radio communications are affected and the six-wheeled, car-sized robotic rover cautiously remains parked at this spot for now. The view looks back toward the stomping grounds for Curiosity's nearly 10.6 kilometer trek so far, with the hazy rim of Gale Crater in the distance. The mosaicked...
  • Astronomy Picture of the Day -- The Medusa Nebula

    06/12/2015 4:11:16 AM PDT · by SunkenCiv · 8 replies
    NASA ^ | June 12, 2015 | (see photo credit)
    Explanation: Braided, serpentine filaments of glowing gas suggest this nebula's popular name, The Medusa Nebula. Also known as Abell 21, this Medusa is an old planetary nebula some 1,500 light-years away along the southern border of the constellation Gemini. Like its mythological namesake, the nebula is associated with a dramatic transformation. The planetary nebula phase represents a final stage in the evolution of low mass stars like the sun, as they transform themselves from red giants to hot white dwarf stars and in the process shrug off their outer layers. Ultraviolet radiation from the hot star powers the nebular glow....
  • Astronomy Picture of the Day -- The Light, the Dark, and the Dusty

    06/11/2015 4:01:59 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | June 11, 2015 | (see photo credit)
    Explanation: This colorful skyscape spans about three full moons (1.5 degrees) across nebula rich starfields along the plane of our Milky Way Galaxy in the royal northern constellation Cepheus. Near the edge of the region's massive molecular cloud some 2,400 light-years away, bright reddish emission region Sharpless (Sh) 155 lies at the upper left, also known as the Cave Nebula. About 10 light-years across the cosmic cave's bright rims of gas are ionized by ultraviolet light from hot young stars. Dusty blue reflection nebulae also abound on the interstellar canvas cut by dense obscuring clouds of dust. The long core...