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Astronomy Picture of the Day (General/Chat)

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  • Astronomy Picture of the Day -- Orbits of Potentially Hazardous Asteroids

    08/12/2013 3:44:40 AM PDT · by SunkenCiv · 14 replies
    NASA ^ | August 12, 2013 | (see photo credit)
    Explanation: Are asteroids dangerous? Some are, but the likelihood of a dangerous asteroid striking the Earth during any given year is low. Because some past mass extinction events have been linked to asteroid impacts, however, humanity has made it a priority to find and catalog those asteroids that may one day affect life on Earth. Pictured above are the orbits of the over 1,000 known Potentially Hazardous Asteroids (PHAs). These documented tumbling boulders of rock and ice are over 140 meters across and will pass within 7.5 million kilometers of Earth -- about 20 times the distance to the Moon....
  • Astronomy Picture of the Day -- M74: The Perfect Spiral

    08/12/2013 3:44:34 AM PDT · by SunkenCiv · 7 replies
    NASA ^ | August 11, 2013 | (see photo credit)
    Explanation: If not perfect, then this spiral galaxy is at least one of the most photogenic. An island universe of about 100 billion stars, 32 million light-years away toward the constellation Pisces, M74 presents a gorgeous face-on view. Classified as an Sc galaxy, the grand design of M74's graceful spiral arms are traced by bright blue star clusters and dark cosmic dust lanes. Constructed from image data recorded in 2003 and 2005, this sharp composite is from the Hubble Space Telescope's Advanced Camera for Surveys. Spanning about 30,000 light-years across the face of M74, it includes exposures recording emission from...
  • Astronomy Picture of the Day -- Perseids over Meteora

    08/10/2013 2:36:00 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | August 10, 2013 | (see photo credit)
    Explanation: The two bright meteors flashing through this night skyscape from August 7 are part of the ongoing Perseid meteor shower. In the direction indicated by both colorful streaks, the shower's radiant in the eponymous constellation Perseus is at the upper right. North star Polaris, near the center of all the short, arcing star trails is at the upper left. But also named for its pose against the sky, the monastery built on the daunting sandstone cliffs in the foreground is part of Meteora. A World Heritage site, Meteora is a historic complex of lofty monasteries located near Kalabaka in...
  • Astronomy Picture of the Day -- Perseid over Albrechtsberg Castle

    08/10/2013 2:35:55 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | August 09, 2013 | (see photo credit)
    Explanation: Medieval Albrechtsberg castle is nestled in trees near the northern bank of the river Pielach and the town of Melk, Austria. In clearing night skies on August 12, 2012 it stood under constellations of the northern summer, including Aquarius, Aquila, and faint, compact Delphinus (above and right of center) in this west-looking skyview. The scene also captures a bright meteor above the castle walls. Part of the annual perseid meteor shower, its trail points back toward the heroic constellation Perseus high above the horizon in the early morning hours. Entering the atmosphere at about 60 kilometers per second, perseid...
  • Astronomy Picture of the Day -- NGC 3370: A Sharper View

    08/07/2013 9:37:45 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | August 08, 2013 | (see photo credit)
    Explanation: Similar in size and grand design to our own Milky Way, spiral galaxy NGC 3370 lies about 100 million light-years away toward the constellation Leo. Recorded here in exquisite detail by the Hubble Space Telescope's Advanced Camera for Surveys, the big, beautiful face-on spiral does steal the show, but the sharp image also reveals an impressive array of background galaxies in the field, strewn across the more distant Universe. Looking within NGC 3370, the image data has proved sharp enough to study individual pulsating stars known as Cepheids that can be used to accurately determine this galaxy's distance. NGC...
  • Astronomy Picture of the Day -- Meteors and Aurorae over Iceland

    08/07/2013 9:35:43 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | August 07, 2013 | (see photo credit)
    Explanation: What's going on behind that mountain? Quite a bit. First of all, the mountain itself, named Kirkjufell, is quite old and located in western Iceland near the town of Grundarfj%C3%B6r%C3%B0ur. In front of the steeply-sloped structure lies a fjord that had just begun to freeze when the above image was taken -- in mid-December of 2012. Although quite faint to the unaided eye, the beautiful colors of background aurorae became quite apparent on the 25-second exposure. What makes Geminids meteor shower -- meteors that might not have been evident were the aurora much brighter. Far in the distance, on...
  • Astronomy Picture of the Day -- In the Vicinity of the Cone Nebula

    08/06/2013 6:48:08 PM PDT · by SunkenCiv · 20 replies
    NASA ^ | August 06, 2013 | (see photo credit)
    Explanation: Strange shapes and textures can be found in neighborhood of the Cone Nebula. The unusual shapes originate from fine interstellar dust reacting in complex ways with the energetic light and hot gas being expelled by the young stars. The brightest star on the right of the above picture is S Mon, while the region just below it has been nicknamed the Fox Fur Nebula for its color and structure. The blue glow directly surrounding S Mon results from reflection, where neighboring dust reflects light from the bright star. The red glow that encompasses the whole region results not only...
  • Astronomy Picture of the Day -- Leaving Earth

    08/05/2013 3:59:08 AM PDT · by SunkenCiv · 20 replies
    NASA ^ | August 05, 2013 | (see photo credit)
    Explanation: What it would look like to leave planet Earth? Such an event was recorded visually in great detail by the MESSENGER spacecraft as it swung back past the Earth, eight years ago, on its way in toward the planet Mercury. Earth can be seen rotating in this time-lapse video, as it recedes into the distance. The sunlit half of Earth is so bright that background stars are not visible. The robotic MESSENGER spacecraft is now in orbit around Mercury and has recently concluded the first complete map of the surface. On occasion, MESSENGER has continued to peer back at...
  • Astronomy Picture of the Day -- Io's Surface: Under Construction

    08/03/2013 10:20:09 PM PDT · by SunkenCiv · 28 replies
    NASA ^ | August 04, 2013 | (see photo credit)
    Explanation: Like the downtown area of your favorite city and any self-respecting web site ... Io's surface is constantly under construction. This moon of Jupiter holds the distinction of being the Solar System's most volcanically active body -- its bizarre looking surface continuously formed and reformed by lava flows. Generated using 1996 data from NASA's Galileo spacecraft, this high resolution composite image is centered on the side of Io that always faces away from Jupiter. It has been enhanced to emphasize Io's surface brightness and color variations, revealing features as small as 1.5 miles across. The notable absence of impact...
  • Astronomy Picture of the Day -- Twisting with NGC 3718

    08/03/2013 5:53:25 AM PDT · by SunkenCiv · 4 replies
    NASA ^ | August 03, 2013 | (see photo credit)
    Explanation: A careful look at this colorful cosmic snapshot reveals a surprising number of galaxies both near and far toward the constellation Ursa Major. The most striking is NGC 3718, the warped spiral galaxy near picture center. NGC 3718's spiral arms look twisted and extended, mottled with young blue star clusters. Drawn out dust lanes obscure its yellowish central regions. A mere 150 thousand light-years to the right is another large spiral galaxy, NGC 3729. The two are likely interacting gravitationally, accounting for the peculiar appearance of NGC 3718. While this galaxy pair lies about 52 million light-years away, the...
  • Astronomy Picture of the Day -- Tropic of Cancer

    08/02/2013 4:08:29 AM PDT · by SunkenCiv · 12 replies
    NASA ^ | August 02, 2013 | (see photo credit)
    Explanation: This intriguing monument can be found in Taiwan between the cities of Hualian and Taitong. Split into two sides, it straddles a special circle of latitude on planet Earth, near 23.5 degrees north, known as the Tropic of Cancer. Points along the Tropic of Cancer are the northernmost locations where the Sun can pass directly overhead, an event that occurs once a year during the northern hemisphere's summer solstice. The latitude that defines the Tropic of Cancer corresponds to the tilt of planet Earth's rotation axis with respect to its orbital plane. The name refers to the zodiacal constellation...
  • Astronomy Picture of the Day -- Moon Over Andromeda

    08/01/2013 7:27:04 PM PDT · by SunkenCiv · 15 replies
    NASA ^ | August 01, 2013 | (see photo credit)
    Explanation: The Great Spiral Galaxy in Andromeda (aka M31), a mere 2.5 million light-years distant, is the closest large spiral to our own Milky Way. Andromeda is visible to the unaided eye as a small, faint, fuzzy patch, but because its surface brightness is so low, casual skygazers can't appreciate the galaxy's impressive extent in planet Earth's sky. This entertaining composite image compares the angular size of the nearby galaxy to a brighter, more familiar celestial sight. In it, a deep exposure of Andromeda, tracing beautiful blue star clusters in spiral arms far beyond the bright yellow core, is combined...
  • Astronomy Picture of the Day -- 130 Years of Earth Surface Temperatures [AGW Agitprop / Barf Alert]

    07/31/2013 5:25:46 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | July 31, 2013 | (see photo credit)
    Explanation: How has the surface temperature of Earth been changing? To help find out, Earth scientists collected temperature records from over 1000 weather stations around the globe since 1880, and combined them with modern satellite data. The above movie dramatizes the result showing 130 years of planet-wide temperature changes relative to the local average temperatures in the mid-1900s. In the above global maps, red means warmer and blue means colder. On average, the display demonstrates that the temperature on Earth has increased by nearly one degree Celsius over the past 130 years, and many of the warmest years on record...
  • Astronomy Picture of the Day -- The Eskimo Nebula from Hubble and Chandra

    07/30/2013 7:27:17 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | July 30, 2013 | (see photo credit)
    Explanation: In 1787, astronomer William Herschel discovered the Eskimo Nebula. From the ground, NGC 2392 resembles a person's head surrounded by a parka hood. In 2000, the Hubble Space Telescope imaged the Eskimo Nebula in visible light, while the nebula was imaged in X-rays by the Chandra X-ray Observatory in 2007. The above combined visible-X ray image, with X-rays emitted by central hot gas and shown in pink, was released last week. From space, the nebula displays gas clouds so complex they are not fully understood. The Eskimo Nebula is clearly a planetary nebula, and the gas seen above composed...
  • Astronomy Picture of the Day -- Saturn, Titan, Rings, and Haze

    07/29/2013 3:32:58 PM PDT · by SunkenCiv · 13 replies
    NASA ^ | July 29, 2013 | (see photo credit)
    Explanation: This is not a solar eclipse. Pictured above is a busy vista of moons and rings taken at Saturn. The large circular object in the center of the image is Titan, the largest moon of Saturn and one of the most intriguing objects in the entire Solar System. The dark spot in the center is the main solid part of the moon. The bright surrounding ring is atmospheric haze above Titan, gas that is scattering sunlight to a camera operating onboard the robotic Cassini spacecraft. Cutting horizontally across the image are the rings of Saturn, seen nearly edge on....
  • Astronomy Picture of the Day -- Hoag's Object: A Strange Ring Galaxy

    07/28/2013 1:57:51 AM PDT · by SunkenCiv · 8 replies
    NASA ^ | July 28, 2013 | (see photo credit)
    Explanation: Is this one galaxy or two? This question came to light in 1950 when astronomer Art Hoag chanced upon this unusual extragalactic object. On the outside is a ring dominated by bright blue stars, while near the center lies a ball of much redder stars that are likely much older. Between the two is a gap that appears almost completely dark. How Hoag's Object formed remains unknown, although similar objects have now been identified and collectively labeled as a form of ring galaxy. Genesis hypotheses include a galaxy collision billions of years ago and the gravitational effect of a...
  • Astronomy Picture of the Day -- Atacama's Cloudy Night

    07/27/2013 7:56:35 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | July 27, 2013 | (see photo credit)
    Explanation: Storm clouds do sometimes come to Chile's Atacama desert, known as the driest place on Earth. These washed through the night sky just last month during the winter season, captured in this panoramic view. Drifting between are cosmic clouds more welcome by the region's astronomical residents though, including dark dust clouds in silhouette against the crowded starfields and nebulae of the central Milky Way. Below and right of center lies the Large Magellanic Cloud, appropriately named for its appearance in starry southern skies. City lights about 200 kilometers distant still glow along the horizon at the right, while bright...
  • Astronomy Picture of the Day -- The Elephant's Trunk in IC 1396

    07/25/2013 10:08:07 PM PDT · by SunkenCiv · 1 replies
    NASA ^ | July 26, 2013 | (see photo credit)
    Explanation: Like an illustration in a galactic Just So Story, the Elephant's Trunk Nebula winds through the emission nebula and young star cluster complex IC 1396, in the high and far off constellation of Cepheus. Of course, the cosmic elephant's trunk is over 20 light-years long. This composite was recorded through narrow band filters that transmit the light from ionized hydrogen, sulfur, and oxygen atoms in the region. The resulting image highlights the bright swept-back ridges that outline pockets of cool interstellar dust and gas. Such embedded, dark, tendril-shaped clouds contain the raw material for star formation and hide protostars...
  • Astronomy Picture of the Day -- The Beautiful Trifid

    07/25/2013 4:39:18 PM PDT · by SunkenCiv · 19 replies
    NASA ^ | July 25, 2013 | (see photo credit)
    Explanation: The beautiful Trifid Nebula is a cosmic study in contrasts. Also known as M20, it lies about 5,000 light-years away toward the nebula rich constellation Sagittarius. A star forming region in the plane of our galaxy, the Trifid illustrates three different types of astronomical nebulae; red emission nebulae dominated by light emitted by hydrogen atoms, blue reflection nebulae produced by dust reflecting starlight, and dark nebulae where dense dust clouds appear in silhouette. The bright red emission region, roughly separated into three parts by obscuring dust lanes, lends the Trifid its popular name. But in this sharp, colorful scene,...
  • Astronomy Picture of the Day -- A Year of Sky on Earth

    07/25/2013 4:39:17 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | July 24, 2013 | (see photo credit)
    Explanation: Each panel shows one day. With 360 movie panels, the sky over (almost) an entire year is shown in time lapse format as recorded by a video camera on the roof of the Exploratorium museum in San Francisco, California. The camera recorded an image every 10 seconds from before sunrise to after sunset and from mid-2009 to mid-2010. A time stamp showing the local time of day is provided on the lower right. The videos are arranged chronologically, with July 28 shown on the upper left, and January 1 located about about half way down. Although every day lasts...
  • Astronomy Picture of the Day -- Two Views of Earth

    07/24/2013 3:46:18 AM PDT · by SunkenCiv · 12 replies
    NASA ^ | July 23, 2013 | (see photo credit)
    Explanation: In a cross-Solar System interplanetary first, our Earth was photographed during the same day from both Mercury and Saturn. Pictured on the left, Earth is the pale blue dot just below the rings of Saturn, as captured by the robotic Cassini spacecraft now orbiting the gas giant. Pictured on the right, the Earth-Moon system is seen against a dark background, as captured by the robotic MESSENGER spacecraft now orbiting Mercury. In the MESSENGER image, the Earth (left) and Moon (right) shine brightly with reflected sunlight. MESSENGER took the overexposed image last Friday as part of a search for small...
  • Astronomy Picture of the Day -- Earth and Moon from Saturn

    07/22/2013 3:28:02 AM PDT · by SunkenCiv · 14 replies
    NASA ^ | July 22, 2013 | (see photo credit)
    Explanation: You are here. Everyone you've ever known is here. Every human who has ever lived -- is here. Pictured above is the Earth-Moon system as captured by the Cassini mission orbiting Saturn in the outer Solar System. Earth is the brighter of the two spots near the center, while the Moon is visible to its lower left. The unprocessed image shows several streaks that are not stars but rather cosmic rays that struck the digital camera while it was taking the image. The image was snapped by Cassini on Friday and released on Saturday. At nearly the same time,...
  • Astronomy Picture of the Day -- The Seasons of Saturn

    07/21/2013 4:53:20 PM PDT · by SunkenCiv · 3 replies
    NASA ^ | July 21, 2013 | (see photo credit)
    Explanation: Since Saturn's axis is tilted as it orbits the Sun, Saturn has seasons, like those of planet Earth ... but Saturn's seasons last for over seven years. So what season is it on Saturn now? Orbiting the equator, the tilt of the rings of Saturn provides quite a graphic seasonal display. Each year until 2016, Saturn's rings will be increasingly apparent after appearing nearly edge-on in 2009. The ringed planet is also well placed in evening skies providing a grand view as summer comes to Saturn's northern hemisphere and winter to the south. The Hubble Space Telescope took the...
  • Astronomy Picture of the Day -- Comet Lemmon and the Deep Sky

    07/20/2013 3:12:16 AM PDT · by SunkenCiv · 6 replies
    NASA ^ | July 20, 2013 | (see photo credit)
    Explanation: Now sweeping high above the ecliptic plane, Comet Lemmon has faded dramatically in planet Earth's night sky as it heads for the outer solar system. Some 16 light-minutes (2 AU) from the Sun, it still sports a greenish coma though, posing on the right in this 4 degree wide telescopic view from last Saturday with deep sky star clusters and nebulae in Cassiopeia. In fact, the rich background skyscape is typical within the boundaries of the boastful northern constellation that lie along the crowded starfields of the Milky Way. Included near center is open star cluster M52 about 5,000...
  • Astronomy Picture of the Day -- Take a Picture of Saturn

    07/19/2013 3:41:41 PM PDT · by SunkenCiv · 9 replies
    NASA ^ | July 19, 2013 | (see photo credit)
    Explanation: Take a picture of Saturn in the sky tonight. You could capture a view like this one. Recorded just last month looking toward the south, planet Earth and ruins of the ancient temple of Athena at Assos, Turkey are in the foreground. The Moon rises at the far left of the frame and Saturn is the bright "star" at the upper right, near Virgo's alpha star Spica (picture with labels). If you do take a picture of Saturn or wave at Saturn and take a picture, you can share it online and submit it to the Saturn Mosaic Project....
  • Astronomy Picture of the Day -- Hidden Galaxy IC 342

    07/18/2013 2:48:12 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | July 18, 2013 | (see photo credit)
    Explanation: Similar in size to large, bright spiral galaxies in our neighborhood, IC 342 is a mere 10 million light-years distant in the long-necked, northern constellation Camelopardalis. A sprawling island universe, IC 342 would otherwise be a prominent galaxy in our night sky, but it is hidden from clear view and only glimpsed through the veil of stars, gas and dust clouds along the plane of our own Milky Way galaxy. Even though IC 342's light is dimmed by intervening cosmic clouds, this deep telescopic image traces the galaxy's obscuring dust, blue star clusters, and glowing pink star forming regions...
  • Astronomy Picture of the Day -- A Waterspout in Florida

    07/17/2013 12:05:07 AM PDT · by SunkenCiv · 19 replies
    NASA ^ | July 17, 2013 | (see photo credit)
    Explanation: What's happening over the water? Pictured above is one of the better images yet recorded of a waterspout, a type of tornado that occurs over water. Waterspouts are spinning columns of rising moist air that typically form over warm water. Waterspouts can be as dangerous as tornadoes and can feature wind speeds over 200 kilometers per hour. Some waterspouts form away from thunderstorms and even during relatively fair weather. Waterspouts may be relatively transparent and initially visible only by an unusual pattern they create on the water. The above image was taken earlier this month near Tampa Bay, Florida....
  • Astronomy Picture of the Day -- The Sombrero Galaxy from Hale

    07/17/2013 12:01:16 AM PDT · by SunkenCiv · 4 replies
    NASA ^ | July 15, 2013 | (see photo credit)
    Explanation: What's going on in the center of this spiral galaxy? Named the Sombrero Galaxy for its hat-like resemblance, M104 features a prominent dust lane and a bright halo of stars and globular clusters. Reasons for the Sombrero's hat-like appearance include an 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 visible in the above image from the 200-inch Hale Telescope. Close inspection of the central bulge shows many points of light that...
  • Astronomy Picture of the Day -- The Moon from Zond 8

    07/16/2013 4:04:05 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | July 16, 2013 | (see photo credit)
    Explanation: Which moon is this? Earth's. Our Moon's unfamiliar appearance is due partly to an unfamiliar viewing angle as captured by a little-known spacecraft -- the Soviet Union's Zond 8 that circled the Moon in October of 1970. Pictured above, the dark-centered circular feature that stands out near the top of the image is Mare Orientale, a massive impact basin formed by an ancient collision with an asteroid. Mare Orientale is surrounded by light colored and highly textured highlands. Across the image bottom lies the dark and expansive Oceanus Procellarum, the largest of the dark (but dry) maria that dominate...
  • Astronomy Picture of the Day -- The Pillars of Eagle Castle

    07/13/2013 10:04:36 PM PDT · by SunkenCiv · 8 replies
    NASA ^ | July 14, 2013 | (see photo credit)
    Explanation: What lights up this castle of star formation? The familiar Eagle Nebula glows bright in many colors at once. The above image is a composite of three of these glowing gas colors. Pillars of dark dust nicely outline some of the denser towers of star formation. Energetic light from young massive stars causes the gas to glow and effectively boils away part of the dust and gas from its birth pillar. Many of these stars will explode after several million years, returning most of their elements back to the nebula which formed them. This process is forming an open...
  • Astronomy Picture of the Day -- Sunspot at Sunset

    07/12/2013 9:54:50 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | July 13, 2013 | (see photo credit)
    Explanation: Reddened rays of the setting Sun flooded the skies over Cedar Creek Lake, southeast of Dallas, Texas, planet Earth on July 6th. And while sunsets may be the most watched celestial event, this one even offered something extra. A sunspot so large it was visible to the naked eye is captured in the serene sunset view, near the center of a solar disk dimmed and distorted by Earth's dense atomosphere. Telescopic views revealed the spot to be a complex of large solar active regions composed of sunspots, some larger than planet Earth itself.
  • Astronomy Picture of the Day -- Messier's Eleven

    07/12/2013 3:59:42 PM PDT · by SunkenCiv · 11 replies
    NASA ^ | July 12, 2013 | (see photo credit)
    Explanation: This fifteen degree wide field of view stretches across the crowded starfields of Sagittarius toward the center of our Milky Way galaxy. In fact, the center of the galaxy lies near the right edge of the rich starscape and eleven bright star clusters and nebulae fall near the center of the frame. All eleven are numbered entries in the catalog compiled by 18th century cosmic tourist Charles Messier. Gaining celebrity status with skygazers, M8 (Lagoon), M16 (Eagle), M17 (Omega), and M20 (Trifid) show off the telltale reddish hues of emission nebulae associated with star forming regions. But also eye-catching...
  • Astronomy Picture of the Day -- Dusty Nebulae in Taurus

    07/11/2013 3:49:39 PM PDT · by SunkenCiv · 2 replies
    NASA ^ | July 11, 2013 | (see photo credit)
    Explanation: This complex of dusty nebulae linger along the edge of the Taurus molecular cloud, a mere 450 light-years distant. Stars are forming on the cosmic scene, including extremely youthful star RY Tauri prominent toward the upper left of the 1.5 degree wide telescopic field. In fact RY Tauri is a pre-main sequence star, embedded in its natal cloud of gas and dust, also cataloged as reflection nebula vdB 27. Highly variable, the star is still relatively cool and in the late phases of gravitational collapse. It will soon become a stable, low mass, main sequence star, a stage of...
  • Astronomy Picture of the Day -- Large Sunspots Now Crossing the Sun

    07/10/2013 3:18:29 PM PDT · by SunkenCiv · 13 replies
    NASA ^ | July 10, 2013 | (see photo credit)
    Explanation: One of the largest sunspot regions in recent years is now crossing the Sun. This region of convoluted magnetic fields may well produce a solar flare that releases a cloud of energetic particles into the Solar System. Were a very powerful cloud to impact the Earth's magnetosphere, it could be dangerous to Earth-orbiting astronauts and satellites. Conversely, the impact of even a less energetic cloud might create picturesque aurora. Pictured above is the sunspot region as it appeared two days ago. The rightmost part of this region has been cataloged as AR 11785, while the left part as AR...
  • Astronomy Picture of the Day -- Supergiant Star Gamma Cygni

    07/09/2013 2:31:21 AM PDT · by SunkenCiv · 7 replies
    NASA ^ | July 09, 2013 | (see photo credit)
    Explanation: Supergiant star Gamma Cygni lies at the center of the Northern Cross, a famous asterism in the constellation of the Swan (Cygnus). Known by the proper name Sadr, the bright star also lies at the center of this gorgeous skyscape, featuring a complex of stars, dust clouds, and glowing nebulae along the plane of our Milky Way galaxy. The field of view spans over 3 degrees (six Full Moons) on the sky and includes emission nebula IC 1318 and open star cluster NGC 6910. Left of Gamma Cygni and shaped like two glowing cosmic wings divided by a long...
  • Astronomy Picture of the Day -- Pluto's Newly Discovered Moons Receive Names

    07/08/2013 6:15:08 PM PDT · by SunkenCiv · 29 replies
    NASA ^ | July 08, 2013 | (see photo credit)
    Explanation: Pluto's newly discovered moons now have names. Known previously as P4 and P5, the International Astronomical Union has now given the fourth and fifth discovered moons of Pluto the names Kerberos and Styx. The small moons were discovered in 2011 and 2012 by the Hubble Space Telescope in preparation for the close passing of the New Horizons spacecraft by Pluto in 2015. Kerberos is named for the many headed dog in Greek mythology that guards the entrance to the underworld, while Styx is named for the goddess who overlooks the mythological river that runs between the Earth and the...
  • Astronomy Picture of the Day -- NGC 2170: Still Life with Reflecting Dust

    07/07/2013 5:52:49 AM PDT · by SunkenCiv · 1 replies
    NASA ^ | July 07, 2013 | (see photo credit)
    Explanation: In this beautiful celestial still life composed with a cosmic brush, dusty nebula NGC 2170 shines at the upper left. Reflecting the light of nearby hot stars, NGC 2170 is joined by other bluish reflection nebulae, a compact red emission region, and streamers of obscuring dust against a backdrop of stars. Like the common household items still life painters often choose for their subjects, the clouds of gas, dust, and hot stars pictured here are also commonly found in this setting - a massive, star-forming molecular cloud in the constellation of the Unicorn (Monoceros). The giant molecular cloud, Mon...
  • Astronomy Picture of the Day -- NGC 6384: Spiral Beyond the Stars

    07/05/2013 9:20:59 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | July 06, 2013 | (see photo credit)
    Explanation: The universe is filled with galaxies. But to see them astronomers must look out beyond the stars of our own galaxy, the Milky Way. This colorful Hubble Space Telescopic portrait features spiral galaxy NGC 6384, about 80 million light-years away in the direction of the constellation Ophiuchus. At that distance, NGC 6384 spans an estimated 150,000 light-years, while the Hubble close-up of the galaxy's central region is about 70,000 light-years wide. The sharp image shows details in the distant galaxy's blue star clusters and dust lanes along magnificent spiral arms, and a bright core dominated by yellowish starlight. Still,...
  • Astronomy Picture of the Day -- Globular Star Cluster NGC 6752

    07/05/2013 5:24:13 PM PDT · by SunkenCiv · 4 replies
    NASA ^ | July 05, 2013 | (see photo credit)
    Explanation: Some 13,000 light-years away toward the southern constellation Pavo, the globular star cluster NGC 6752 roams the halo of our Milky Way galaxy. Over 10 billion years old, NGC 6752 follows clusters Omega Centauri and 47 Tucanae as the third brightest globular in planet Earth's night sky. It holds over 100 thousand stars in a sphere about 100 light-years in diameter. Telescopic explorations of the NGC 6752 have found that a remarkable fraction of the stars near the cluster's core, are multiple star systems. They also reveal the presence of blue straggle stars, stars which appear to be too...
  • Astronomy Picture of the Day -- M82: Starburst Galaxy with a Superwind

    07/03/2013 9:12:20 PM PDT · by SunkenCiv · 4 replies
    NASA ^ | July 04, 2013 | (see photo credit)
    Explanation: Also known as the Cigar Galaxy for its elongated visual appearance, M82 is a starburst galaxy with a superwind. In fact, through ensuing supernova explosions and powerful winds from massive stars, the burst of star formation in M82 is driving a prodigious outflow of material. Evidence for the superwind from the galaxy's central regions is clear in this sharp telescopic snapshot. The composite image highlights emission from long outflow filaments of atomic hydrogen gas in reddish hues. Some of the gas in the superwind, enriched in heavy elements forged in the massive stars, will eventually escape into intergalactic space....
  • Astronomy Picture of the Day -- Stars and Lightning Over Greece

    07/03/2013 5:37:25 PM PDT · by SunkenCiv · 3 replies
    NASA ^ | July 03, 2013 | (see photo credit)
    Explanation: It may appear, at first, like the Galaxy is producing the lightning, but really it's the Earth. In the foreground of the above picturesque nighttime landscape is the Greek Island of Corfu, with town lights surrounding Lake Korrision. Visible farther in the distance are lights from the town of Preveza on the Greek mainland. In the more distant sky a thunderstorm is threatening, with two lightning strokes caught together during this 45 second wide-angle exposure taken in mid-May. The lightning branch on the left appears to be striking near Preveza, whereas the lightning strike on the right appears to...
  • Astronomy Picture of the Day -- Circling a Black Hole at its Photon Sphere

    07/03/2013 5:34:55 PM PDT · by SunkenCiv · 3 replies
    NASA ^ | July 02, 2013 | (see photo credit)
    Explanation: What would it look like to go right up to a black hole? One particularly interesting place near a black hole is its photon sphere, where photons can orbit in circles, a sphere 50 percent further out than the event horizon. Were you to look out from the photon sphere of a black hole, half of the sky would appear completely black, half of the sky would appear unusually bright, and the back of your head would appear across the middle. The above computer-animated video depicts this view from the photon sphere. The reason that the lower region, as...
  • Astronomy Picture of the Day -- Orbiting a Black Hole

    07/01/2013 3:10:55 AM PDT · by SunkenCiv · 10 replies
    NASA ^ | July 01, 2013 | (see photo credit)
    Explanation: What would it look like to orbit a black hole? Since the strong gravity of the black hole can significantly alter light paths, conditions would indeed look strange. For one thing, the entire sky would be visible, since even stars behind the black hole would have their light bent to the observer's eye. For another, the sky near the black hole would appear significantly distorted, with more and more images of the entire sky visible increasingly near the black hole. Most visually striking, perhaps, is the outermost sky image completely contained inside an easily discernible circle known as the...
  • Astronomy Picture of the Day -- Saturn's Hyperion: A Moon with Odd Craters

    06/30/2013 9:00:49 PM PDT · by SunkenCiv · 31 replies
    NASA ^ | June 30, 2013 | (see photo credit)
    Explanation: What lies at the bottom of Hyperion's strange craters? Nobody's sure. To help find out, the robot Cassini spacecraft now orbiting Saturn swooped past the sponge-textured moon in 2005 and 2010 and took images of unprecedented detail. An image from the 2005 pass, shown above in false color, shows a remarkable world strewn with strange craters and a generally odd surface. The slight differences in color likely show differences in surface composition. At the bottom of most craters lies some type of unknown dark material. Inspection of the image shows bright features indicating that the dark material might be...
  • Astronomy Picture of the Day -- PanSTARRS: The Anti Tail Comet

    06/29/2013 7:51:12 PM PDT · by SunkenCiv · 2 replies
    NASA ^ | June 29, 2013 | (see photo credit)
    Explanation: Once known as Earth's sunset comet, PanSTARRS (C/2011 L4) is up all night now, but only for northern hemisphere skygazers. Telescopes are required to track its progress as it fades and heads for the outer solar system. But because planet Earth passed through the comet's orbital plane in late May, PanSTARRS will also be remembered for its remarkably long anti-tail. That edge-on perspective looking along the broad, fanned-out dust tail as it trailed behind the comet created the appearance of an anti-tail pointing in the sunward direction, back toward the inner solar system. Recorded on the night of May...
  • Astronomy Picture of the Day -- A Super Moon's Halo

    06/28/2013 4:11:24 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | June 28, 2013 | (see photo credit)
    Explanation: A Full Perigee Moon rose as the Sun set last Sunday. At its closest to Earth it was, by just a bit, the year's brightest and largest Full Moon also known as a Super Moon. Seen from Punta Piedras, Argentina and the mouth of the Rio de La Plata, near Buenos Aires, the Super Moon's light created this magnificent circular lunar halo. Still, the size of a lunar halo is determined by the geometry of six sided water ice crystals in planet Earth's high, thin clouds. The crystals deflect the rays of moonlight more strongly through a minimum angle...
  • Astronomy Picture of the Day -- Noctilucent Clouds over Moscow

    06/27/2013 4:17:54 AM PDT · by SunkenCiv · 8 replies
    NASA ^ | June 27, 2013 | (see photo credit)
    Explanation: This panoramic night scene from June 8 looks out across a Moscow skyline from atop the main building of Lomonosov Moscow State University. Shining in the darkened sky above are widespread noctilucent clouds. From the edge of space, about 80 kilometers above Earth's surface, the icy clouds can still reflect sunlight even though the Sun itself is below the horizon as seen from the ground. Usually spotted at high latitudes in summer months the diaphanous apparitions, also known as polar mesospheric clouds, have come early this season. The seasonal clouds are understood to form as water vapor driven into...
  • Astronomy Picture of the Day -- M31: The Andromeda Galaxy

    06/25/2013 9:10:35 PM PDT · by SunkenCiv · 26 replies
    NASA ^ | June 26, 2013 | (see photo credit)
    Explanation: Andromeda is the nearest major galaxy to our own Milky Way Galaxy. Our Galaxy is thought to look much like Andromeda. Together these two galaxies dominate the Local Group of galaxies. The diffuse light from Andromeda is caused by the hundreds of billions of stars that compose it. The several distinct stars that surround Andromeda's image are actually stars in our Galaxy that are well in front of the background object. Andromeda is frequently referred to as M31 since it is the 31st object on Messier's list of diffuse sky objects. M31 is so distant it takes about two...
  • Astronomy Picture of the Day -- Rock Nest Panorama from Curiosity on Mars

    06/25/2013 3:09:39 AM PDT · by SunkenCiv · 8 replies
    NASA ^ | June 25, 2013 | (see photo credit)
    Explanation: This is Mars -- have a look around. More specifically, this is one area picked for its promise of holding clues to the habitability of Mars to ancient life. To better search for telling leads, the robotic Curiosity rover took a series of detailed images from a location called Rock Nest. Over 900 of these images were then composed into one of the highest resolution images ever created of the red planet -- a composite containing over one billion pixels. Shown above, toward the middle of this image mosaic, is Mt. Sharp, the central peak of the large crater...
  • Astronomy Picture of the Day -- The Porpoise Galaxy from Hubble

    06/24/2013 8:58:11 PM PDT · by SunkenCiv · 20 replies
    NASA ^ | June 24, 2013 | (see photo credit)
    Explanation: What's happening to this spiral galaxy? Just a few hundred million years ago, NGC 2936, the upper of the two large galaxies shown, was likely a normal spiral galaxy -- spinning, creating stars -- and minding its own business. But then it got too close to the massive elliptical galaxy NGC 2937 below and took a dive. Dubbed the Porpoise Galaxy for its iconic shape, NGC 2936 is not only being deflected but also being distorted by the close gravitational interaction. A burst of young blue stars forms the nose of the porpoise toward the left of the upper...