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Astronomy Picture of the Day (General/Chat)

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  • Astronomy Picture of the Day -- Evaporating Blobs of the Carina Nebula

    04/23/2012 8:40:12 PM PDT · by SunkenCiv · 8 replies
    NASA ^ | April 23, 2012 | (see photo credit)
    Explanation: No, they are not alive -- but they are dying. The unusual blobs found in the Carina nebula, some of which are seen floating on the upper right, might best be described as evaporating. Energetic light and winds from nearby stars are breaking apart the dark dust grains that make the iconic forms opaque. Ironically the blobs, otherwise known as dark molecular clouds, frequently create in their midst the very stars that later destroy them. The floating space mountains pictured above by the orbiting Hubble Space Telescope span a few light months. The Great Nebula in Carina itself spans...
  • Astronomy Picture of the Day -- Flowing Barchan Sand Dunes on Mars

    04/22/2012 8:17:03 PM PDT · by SunkenCiv · 6 replies
    NASA ^ | April 22, 2012 | (see photo credit)
    Explanation: When does Mars act like a liquid? Although liquids freeze and evaporate quickly into the thin atmosphere of Mars, persistent winds may make large sand dunes appear to flow and even drip like a liquid. Visible on the above image right are two flat top mesas in southern Mars when the season was changing from Spring to Summer. A light dome topped hill is also visible on the far left of the image. As winds blow from right to left, flowing sand on and around the hills leaves picturesque streaks. The dark arc-shaped droplets of fine sand are called...
  • Astronomy Picture of the Day -- 3 ATs [Auxiliary Telescopes]

    04/21/2012 7:33:55 AM PDT · by SunkenCiv · 18 replies
    NASA ^ | April 21, 2012 | (see photo credit)
    Explanation: Despite their resemblance to R2D2, these three are not the droids you're looking for. Instead, the enclosures house 1.8 meter Auxiliary Telescopes (ATs) at Paranal Observatory in the Atacama Desert region of Chile. The ATs are designed to be used for interferometry, a technique for achieving extremely high resolution observations, in concert with the observatory's 8 meter Very Large Telescope units. A total of four ATs are operational, each fitted with a transporter that moves the telescope along a track allowing different arrays with the large unit telescopes. To work as an interferometer, the light from each telescope is...
  • Astronomy Picture of the Day -- M57: The Ring Nebula

    04/20/2012 4:24:29 PM PDT · by SunkenCiv · 17 replies
    NASA ^ | April 20, 2012 | (see photo credit)
    Explanation: Except for the rings of Saturn, the Ring Nebula (M57) is probably the most famous celestial band. Its classic appearance is understood to be due to perspective - our view from planet Earth looks down the center of a roughly barrel-shaped cloud of glowing gas. But expansive looping structures are seen to extend far beyond the Ring Nebula's familiar central regions in this intriguing composite of ground based and Hubble Space Telescope images with narrowband image data from Subaru. Of course, in this well-studied example of a planetary nebula, the glowing material does not come from planets. Instead, the...
  • Astronomy Picture of the Day -- Discovery Departs

    04/20/2012 4:23:58 PM PDT · by SunkenCiv · 6 replies
    NASA ^ | April 19, 2012 | (see photo credit)
    Explanation: Climbing into cloudy skies, the Space Shuttle Orbiter Discovery (OV-103) took off from Kennedy Space Center Tuesday at 7 am local time. This time, its final departure from KSC, it rode atop a modified Boeing 747 Shuttle Carrier Aircraft. Following a farewell flyover of the Space Coast, Goddard Space Flight Center, and Washington DC, Discovery headed for Dulles International Airport in Virginia, destined to reside at the Smithsonian's National Air and Space Museum Udvar-Hazy Center. Discovery retires as NASA's most traveled shuttle orbiter, covering more than 148 million miles in 39 missions that included the delivery of the Hubble...
  • Astronomy Picture of the Day -- The Flight Deck of Space Shuttle Endeavour

    04/18/2012 8:13:38 PM PDT · by SunkenCiv · 13 replies
    NASA ^ | April 18, 2012 | (see photo credit)
    Explanation: What would it be like to fly a space shuttle? Although the last of NASA's space shuttles has now been retired, it is still fun to contemplate sitting at the controls of one of the humanity's most sophisticated machines. Pictured above is the flight deck of Space Shuttle Endeavour, the youngest shuttle and the second to last ever launched. The numerous panels and displays allowed the computer-controlled orbiter to enter the top of Earth's atmosphere at greater than the speed of sound and -- just thirty minutes later -- land on a runway like an airplane. The retired space...
  • Astronomy Picture of the Day -- Antares and Clouds

    04/16/2012 9:31:35 PM PDT · by SunkenCiv · 13 replies
    NASA ^ | April 17, 2012 | (see photo credit)
    Explanation: Antares is a huge star. In a class called red supergiant, Antares is about 850 times the diameter of our own Sun, 15 times more massive, and 10,000 times brighter. Antares is the brightest star in the constellation of Scorpius and one of the brighter stars in all the night sky. Located about 550 light years away, Antares is seen on the left surrounded by a yellowish nebula of gas which it has itself expelled. Radiation from Antares' blue stellar companion helps cause the nebular gas to glow. Far behind Antares in the above image is the globular star...
  • Astronomy Picture of the Day -- The Eagle Nebula from Kitt Peak

    04/15/2012 9:12:16 PM PDT · by SunkenCiv · 19 replies
    NASA ^ | April 16, 2012 | (see photo credit)
    Explanation: From afar, the whole thing looks like an Eagle. A closer look at the Eagle Nebula, however, shows the bright region is actually a window into the center of a larger dark shell of dust. Through this window, a brightly-lit workshop appears where a whole open cluster of stars is being formed. In this cavity tall pillars and round globules of dark dust and cold molecular gas remain where stars are still forming. Already visible are several young bright blue stars whose light and winds are burning away and pushing back the remaining filaments and walls of gas and...
  • Astronomy Picture of the Day -- Fata Morgana: A Possibly Titanic Mirage

    04/15/2012 7:49:02 PM PDT · by SunkenCiv · 11 replies
    NASA ^ | April 15, 2012 | (see photo credit)
    Explanation: Did this mirage help sink the Titanic? The optical phenomenon called Fata Morgana can make strange shapes or a false wall of water appear above a watery horizon. When conditions are right, light reflecting off of cold water will be bent by an unusual layer of warm air above to arrive at the observer from several different angles. A conceptually comparable mirage can make a setting Sun appear strangely distorted or a distant pavement appear wet. One hundred years ago today, such a Fata Morgana mirage might have obscured real icebergs from the clear view of crew onboard the...
  • Astronomy Picture of the Day -- Six Moons of Saturn

    04/13/2012 10:46:07 PM PDT · by SunkenCiv · 9 replies
    NASA ^ | April 14, 2012 | (see photo credit)
    Explanation: How many moons does Saturn have? So far 62 have been discovered, the smallest only a fraction of a kilometer across. Six of its largest satellites can be seen here, though, in a sharp Saturnian family portrait taken on March 9. Larger than Earth's Moon and even slightly larger than Mercury, Titan has a diameter of 5,150 kilometers and starts the line-up at the lower left. Continuing to the right across the frame are Mimas, Tethys, [Saturn], Enceladus, Dione, and Rhea at far right. Saturn's first known natural satellite, Titan was discovered in 1655 by Dutch astronomer Christiaan Huygens,...
  • Astronomy Picture of the Day -- A Dust Devil of Mars

    04/12/2012 9:44:43 PM PDT · by SunkenCiv · 21 replies
    NASA ^ | April 13, 2012 | (see photo credit)
    Explanation: It was late in the northern martian spring when the HiRISE camera onboard the Mars Reconnaissance Orbiter spied this local denizen. Tracking south and east (down and right) across the flat, dust-covered Amazonis Planitia the core of the whirling dust devil is about 30 meters in diameter. Lofting dust into the thin martian atmosphere, its plume reaches more than 800 meters above the surface. Not following the path of the dust devil, the plume is blown toward the east by a westerly breeze. Common in this region, dust devils occur as the surface is heated by the Sun, generating...
  • Astronomy Picture of the Day -- Yuri's Planet [ NASA celebrates the USSR]

    04/12/2012 4:29:25 AM PDT · by SunkenCiv · 9 replies
    NASA ^ | April 12, 2012 | (see photo credit)
    Explanation: On another April 12th, in 1961, Soviet cosmonaut Yuri Alexseyevich Gagarin became the first human to see planet Earth from space. Commenting on his view from orbit he reported, "The sky is very dark; the Earth is bluish. Everything is seen very clearly". To celebrate, consider this recent image from the orbiting International Space Station. A stunning view of the planet at night from an altitude of 240 miles, it was recorded on March 28. The lights of Moscow, Russia are near picture center and one of the station's solar panel arrays is on the left. Aurora and the...
  • Astronomy Picture of the Day -- Geostationary Satellites Beyond the Alps [video]

    04/11/2012 3:37:20 AM PDT · by SunkenCiv · 16 replies
    NASA ^ | April 11, 2012 | (see photo credit)
    Explanation: Why don't those stars move? Stars in the sky will typically appear to rise and set as the Earth turns. Those far to the north or south will appear to circle the pole. If you look closely at the above time-lapse movie, however, there are points of light that appear stationary. These objects are not stars but human-launched robotic spacecraft that remain fixed high above the Earth's equator. Called geostationary satellites, they don't fall down because they do orbit the Earth -- they just orbit at exactly the same speed that the Earth rotates. The orbital distance where this...
  • Astronomy Picture of the Day -- A Fox Fur, a Unicorn, and a Christmas Tree

    04/09/2012 9:11:52 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | April 10, 2012 | (see photo credit)
    Explanation: What do the following things have in common: a cone, the fur of a fox, and a Christmas tree? Answer: they all occur in the constellation of the unicorn (Monoceros). Pictured above as a star forming region cataloged as NGC 2264, the complex jumble of cosmic gas and dust is about 2,700 light-years distant and mixes reddish emission nebulae excited by energetic light from newborn stars with dark interstellar dust clouds. Where the otherwise obscuring dust clouds lie close to the hot, young stars they also reflect starlight, forming blue reflection nebulae. The above image spans about 3/4 degree...
  • Astronomy Picture of the Day -- Blue Straggler Stars in Globular Cluster M53

    04/09/2012 7:34:49 PM PDT · by SunkenCiv · 9 replies
    NASA ^ | April 09, 2012 | (see photo credit)
    Explanation: If our Sun were part of M53, the night sky would glow like a jewel box of bright stars. M53, also known as NGC 5024, is one of about 250 globular clusters that survive in our Galaxy. Most of the stars in M53 are older and redder than our Sun, but some enigmatic stars appear to be bluer and younger. These young stars might contradict the hypothesis that all the stars in M53 formed at nearly the same time. These unusual stars are known as blue stragglers and are unusually common in M53. After much debate, blue stragglers are...
  • Astronomy Picture of the Day -- Io: Moon Over Jupiter

    04/07/2012 9:45:56 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | April 08, 2012 | (see photo credit)
    Explanation: How big is Jupiter's moon Io? The most volcanic body in the Solar System, Io (usually pronounced "EYE-oh") is 3,600 kilometers in diameter, about the size of planet Earth's single large natural satellite. Gliding past Jupiter at the turn of the millennium, the Cassini spacecraft captured this awe inspiring view of active Io with the largest gas giant as a backdrop, offering a stunning demonstration of the ruling planet's relative size. Although in the above picture Io appears to be located just in front of the swirling Jovian clouds, Io hurtles around its orbit once every 42 hours at...
  • Astronomy Picture of the Day -- Conjunction Haiku

    04/06/2012 9:35:39 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | April 07, 2012 | (see photo credit)
    Explanation: Sister planet stands / together with sister stars. / Celebrate the sky.
  • Astronomy Picture of the Day -- Venus and the Sisters

    04/06/2012 9:46:22 AM PDT · by SunkenCiv · 12 replies
    NASA ^ | April 06, 2012 | (see photo credit)
    Explanation: After wandering about as far from the Sun on the sky as Venus can get, the brilliant evening star crossed paths with the Pleiades star cluster earlier this week. The beautiful conjunction was enjoyed by skygazers around the world. Taken on April 2, this celestial group photo captures the view from Portal, Arizona, USA. Also known as the Seven Sisters, even the brighter naked-eye Pleiades stars are seen to be much fainter than Venus. And while Venus and the sisters do look star-crossed, their spiky appearance is the diffraction pattern caused by multiple leaves in the aperture of the...
  • Astronomy Picture of the Day -- Zodiacal Light Panorama

    04/05/2012 8:07:48 PM PDT · by SunkenCiv · 4 replies
    NASA ^ | April 05, 2012 | (see photo credit)
    Explanation: Sweeping from the eastern to western horizon, this 360 degree panorama follows the band of zodiacal light along the solar system's ecliptic plane. Dust scattering sunlight produces the faint zodiacal glow that spans this fundamental coordinate plane of the celestial sphere, corresponding to the apparent yearly path of the Sun through the sky and the plane of Earth's orbit. The fascinating panorama is a mosaic of images taken from dusk to dawn over the course of a single night at two different locations on Mauna Kea. The lights of Hilo, Hawaii are on the eastern (left) horizon, with the...
  • Astronomy Picture of the Day -- Centaurus A

    04/05/2012 8:07:45 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | April 04, 2012 | (see photo credit)
    Explanation: What's the closest active galaxy to planet Earth? That would be Centaurus A, only 11 million light-years distant. Spanning over 60,000 light-years, the peculiar elliptical galaxy is also known as NGC 5128. Forged in a collision of two otherwise normal galaxies, Centaurus A's fantastic jumble of young blue star clusters, pinkish star forming regions, and imposing dark dust lanes are seen here in remarkable detail. The colorful galaxy portrait was recorded under clear Chilean skies at the Cerro Tololo Inter-American Observatory. Near the galaxy's center, left over cosmic debris is steadily being consumed by a central black hole with...
  • Astronomy Picture of the Day -- M46 & M47: Star Clusters Young and Old

    04/03/2012 8:15:12 PM PDT · by SunkenCiv · 4 replies
    NASA ^ | April 03, 2012 | (see photo credit)
    Explanation: Many stars form in clusters. Galactic or open star clusters are relatively young swarms of bright stars born together near the plane of our Milky Way Galaxy. Separated by about a degree on the sky, two nice examples are M46 (upper left) 5,400 light-years in the distance and M47 (lower right) only 1,600 light-years away toward the nautical constellation Puppis. Around 300 million years young M46 contains a few hundred stars in a region about 30 light-years across. Aged 80 million years, M47 is a smaller but looser cluster of about 50 stars spanning 10 light-years. But this portrait...
  • Astronomy Picture of the Day -- Tungurahua Erupts

    04/01/2012 9:39:26 PM PDT · by SunkenCiv · 6 replies
    NASA ^ | April 02, 2012 | (see photo credit)
    Explanation: Volcano Tungurahua sometimes erupts spectacularly. Pictured above, molten rock so hot it glows visibly pours down the sides of the 5,000-meter high Tungurahua, while a cloud of dark ash is seen being ejected toward the left. Wispy white clouds flow around the lava-lit peak, while a star-lit sky shines in the distance. The above image was captured in 2006 as ash fell around the adventurous photographer. Located in Ecuador, Tungurahua has become active roughly every 90 years since for the last 1,300 years.
  • Astronomy Picture of the Day -- Dad Quiets Omicron Ceti

    03/31/2012 10:43:18 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | April 01, 2012 | (see photo credit)
    Explanation: The Omicron Cetians have been silenced. After alien-like monsters were reported to disturb his daughter's sleep for four nights in a row, this father took action. When last questioned, the daughter seemed to indicate that the hullabaloo might have come from a planetary system possibly sounding like "Omicron Ceti". Getting to the root of the problem, the dad then took his daughter outside and used a powerful laser to blast the alien's home world. Humorously, the parent star Omicron Ceti now shows itself to be unstable and is dramatically increasing its brightness. Happy April Fool's Day from the folks...
  • Astronomy Picture of the Day -- The Grand Canyon in Moonlight

    03/31/2012 3:55:09 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | March 30, 2012 | (see photo credit)
    Explanation: In this alluring night skyscape recorded on March 26, a young Moon stands over the distant western horizon in conjunction with brilliant planet Venus. In the foreground, the Colorado River glistens in moonlight as it winds through the Grand Canyon, seen from the canyon's southern rim at Lipan Point. Of course, the Grand Canyon is known as one of the wonders of planet Earth. Carved by the river, the enormous fissure is about 270 miles (440 kilometers) long, up to 18 miles (30 kilometers) wide and approaches 1 mile (1.6 kilometers) deep. On this date, wonders of the night...
  • Astronomy Picture of the Day -- Paris by Night

    03/31/2012 3:55:10 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | March 31, 2012 | (see photo credit)
    Explanation: Do you recognize the city lights of Paris in this picture? Taken on March 25 from the top of the 210 meter tall Montparnasse skyscraper, many will spot the looming Eiffel Tower, or the large domed structure of Les Invalides (right), or the colorfully lit elevated Metro train line gently curving toward picture center. You can even pick out the Arc de Triomphe close to the horizon on the right. But regardless of your location, the celestial lights near the western horizon should look very familiar. The lovely triple conjuntion of brilliant Venus (top), Jupiter, and a young crescent...
  • Astronomy Picture of the Day -- Rocket Trails in the Milky Way

    03/28/2012 9:12:55 PM PDT · by SunkenCiv · 4 replies
    NASA ^ | March 29, 2012 | (see photo credit)
    Explanation: On March 27, five sounding rockets leapt into early morning skies from NASA's Wallops Flight Facility in Virginia. Part of the Anomalous Transport Rocket EXperiment (ATREX), begining at 4:58 am EDT the rockets launched consecutively at 80 second intervals. Releasing a chemical tracer they created luminous white clouds within Earth's ionosphere at altitudes above 60 to 65 miles, swept along by the poorly understood high-altitude jet stream. (Not the same jet stream that airliners fly through at altitudes of 5 to 6 miles.) Seen along the mid-atlantic region of the United States, the clouds drifted through starry skies, captured...
  • Astronomy Picture of the Day -- Earthshine and Venus Over Sierra de Guadarrama

    03/28/2012 8:16:43 PM PDT · by SunkenCiv · 8 replies
    NASA ^ | March 28, 2012 | (see photo credit)
    Explanation: What just above that ridge? The Moon. Specifically, the Earth's Moon was caught just above the horizon in a young crescent phase. The familiar Moon might look a bit odd as the exposure shows significant Earthshine -- the illumination of the part of the Moon hidden from direct sunlight by the sun-reflecting Earth. Also captured in the image is the bright planet Venus on the right. Venus and Jupiter passed only three degrees from each other last week during a photogenic planetary conjunction. The above image was taken two days ago near Madrid, Spain. The foreground horizon silhouette includes...
  • Astronomy Picture of the Day -- Unusual Hollows Discovered on Planet Mercury

    03/27/2012 4:33:25 AM PDT · by SunkenCiv · 24 replies
    NASA ^ | March 27, 2012 | (see photo credit)
    Explanation: What are those unusual features on planet Mercury? The slightly bluish tinge of features dubbed hollows has been exaggerated on the above image by the robotic MESSENGER spacecraft currently orbiting Mercury. The rounded depressions appear different than impact craters and nothing like them has been noted on Earth's Moon or anywhere else in the Solar System. The above image is a section of the floor of Raditladi impact basin about 40 kilometers wide that includes the mountains of the central peak. One progenitor hypothesis is that the hollows formed from the sublimation of material exposed and heated during the...
  • Astronomy Picture of the Day -- M82: Galaxy with a Supergalactic Wind

    03/26/2012 6:10:48 PM PDT · by SunkenCiv · 15 replies · 17+ views
    NASA ^ | March 26, 2012 | (see photo credit)
    Explanation: What's lighting up the Cigar Galaxy? M82, as this irregular galaxy is also known, was stirred up by a recent pass near large spiral galaxy M81. This doesn't fully explain the source of the red-glowing outwardly expanding gas, however. Recent evidence indicates that this gas is being driven out by the combined emerging particle winds of many stars, together creating a galactic superwind.. The above photographic mosaic highlights a specific color of red light strongly emitted by ionized hydrogen gas, showing detailed filaments of this gas. The filaments extend for over 10,000 light years. The 12-million light-year distant Cigar...
  • Astronomy Picture of the Day -- Barred Spiral Galaxy NGC 1300

    03/25/2012 11:05:15 AM PDT · by SunkenCiv · 7 replies · 1+ views
    NASA ^ | March 25, 2012 | (see photo credit)
    Explanation: Big, beautiful, barred spiral galaxy NGC 1300 lies some 70 million light-years away on the banks of the constellation Eridanus. This Hubble Space Telescope composite view of the gorgeous island universe is one of the largest Hubble images ever made of a complete galaxy. NGC 1300 spans over 100,000 light-years and the Hubble image reveals striking details of the galaxy's dominant central bar and majestic spiral arms. In fact, on close inspection the nucleus of this classic barred spiral itself shows a remarkable region of spiral structure about 3,000 light-years across. Unlike other spiral galaxies, including our own Milky...
  • Astronomy Picture of the Day -- The New Moon in the Old Moon's Arms

    03/23/2012 9:38:06 PM PDT · by SunkenCiv · 7 replies · 1+ views
    NASA ^ | March 24, 2012 | (see photo credit)
    Explanation: Also known as the Moon's ashen glow, Earthshine is Earthlight illuminating the Moon's night side. Taken on Nowruz, the March 20 equinox, from Esfahan, Iran, planet Earth, this telescopic image captures strong Earthshine from an old Moon. The darker earthlit disk is in the arms of a bright sunlit crescent. But the view from the Moon would have been enchanting too. When the Moon appears in Earth's sky as a slender crescent, a dazzlingly bright, nearly full Earth would be seen from the lunar surface. The Earth's brightness due to reflected sunlight is known to be strongly influenced by...
  • Astronomy Picture of the Day -- Messier 9 Close-up

    03/23/2012 9:37:58 PM PDT · by SunkenCiv · 14 replies · 2+ views
    NASA ^ | March 23, 2012 | (see photo credit)
    Explanation: Renown 18th century astronomer Charles Messier described this 9th entry in his famous astronomical catalog as "Nebula, without star, in the right leg of Ophiuchus ...". But Messier 9 (M9) does have stars, known to modern astronomers as a globular cluster of over 300,000 stars within a diameter of about 90 light-years. It lies some 25,000 light-years distant, near the central bulge of our Milky Way galaxy. This Hubble Space Telescope close-up resolves the dense swarm of stars across the cluster's central 25 light-years. At least twice the age of the Sun and deficient in heavy elements, the cluster...
  • Astronomy Picture of the Day -- M95 with Supernova

    03/21/2012 9:22:26 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | March 22, 2012 | (see photo credit)
    Explanation: Barred spiral galaxy M95 is about 75,000 light-years across, comparable in size to our own Milky Way and one of the larger galaxies of the Leo I galaxy group. In fact, it is part of a not quite so famous trio of Leo galaxies with neighbors M96 and M105, about 38 million light-years distant. In this sharp and colorful cosmic portrait, a bright, compact ring of star formation surrounds the galaxy's core. Surrounding the prominent yellowish bar are tightly wound spiral arms traced by dust lanes, young blue star clusters, and telltale pinkish star forming regions. As a bonus,...
  • Astronomy Picture of the Day -- Aurora Over Iceland

    03/20/2012 9:29:04 PM PDT · by SunkenCiv · 18 replies · 1+ views
    NASA ^ | March 21, 2012 | (see photo credit)
    Explanation: If you see a sky like this -- photograph it. Three nights ago in Iceland, an adventurous photographer (pictured) chanced across a sky full of aurora and did just that. Afterwards, by stitching together five smaller photographs, the entire aurora-lit sky was recreated in this 180-degree panorama taken from Vatnajökull glacier. Auroras are sparked by energetic particles from the Sun impacting the magnetic environment around the Earth. Resultant energetic particles such as electrons and protons rain down near the Earth's poles and impact the air. The impacted air molecules obtain excited electrons, and when electrons in oxygen molecules fall...
  • Astronomy Picture of the Day -- Evolution of the Moon [ video ]

    03/20/2012 8:25:49 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | March 20, 2012 | (see photo credit)
    Explanation: What is the history of the Moon? The Moon was likely created from debris expelled when a Mars-sized object violently impacted the Earth about 4.5 billion years ago. Just after gravitationally condensing, as imagined above, the glowing-hot surface of the Moon cooled and cracked. Rocks large and small continued to impact the surface, including a particularly large impact that created Aitken Basin about 4.3 billion years ago. A Heavy Bombardment period then continued for hundreds of millions of years, creating large basins all over the lunar surface. Over the next few billion years lava flowed into Earth-side basins, eventually...
  • Astronomy Picture of the Day -- Sunspot Group 1429 and the Distant Sun

    03/18/2012 9:46:14 PM PDT · by SunkenCiv · 11 replies · 1+ views
    NASA ^ | March 19, 2012 | (see photo credit)
    Explanation: What's that on the Sun? Over the past two weeks, one of the most energetic sunspot regions of recent years crossed the face of the Sun. Active Region 1429, visible above as the group of dark spots on the Sun's upper right, blasted out several solar flares and coronal mass ejections since coming around the edge of the Sun almost a month ago. Fast moving particles from these solar explosions have impacted the Earth and been responsible for many colorful auroras seen over the past two weeks. The picturesque foreground features trees and birds near Merida, Spain, where the...
  • Astronomy Picture of the Day -- Jupiter and Venus from Earth

    03/17/2012 10:20:23 PM PDT · by SunkenCiv · 8 replies · 1+ views
    NASA ^ | March 18, 2012 | (see photo credit)
    Explanation: It was visible around the world. The sunset conjunction of Jupiter and Venus was visible last week almost no matter where you lived on Earth. Anyone on the planet with a clear western horizon at sunset could see them. This week the two are still notable, even though Jupiter has sunk below the brighter Venus. And if you look higher in the sky you can see Mars as well. Pictured above, a creative photographer traveled away from the town lights of Szubin, Poland to image a near closest approach of the two planets almost a week ago. The bright...
  • Astronomy Picture of the Day -- NGC 2683: Edge-On Spiral Galaxy

    03/17/2012 7:38:55 AM PDT · by SunkenCiv · 10 replies · 1+ views
    NASA ^ | March 17, 2012 | (see photo credit)
    Explanation: This elegant island universe is cataloged as NGC 2683. It lies a mere 16 million light-years distant toward the northern constellation Lynx. A spiral galaxy comparable to our own Milky Way, NGC 2683 is seen nearly edge-on in the cosmic vista. Blended light from a large population of old, yellowish stars forms the remarkably bright galactic core. Their starlight silhouettes the dust lanes along winding spiral arms, dotted with NGC 2683's young blue star clusters. The sharp image was recorded through the lens of a refracting telescope that shows brighter foreground Milky Way stars as colorful and round, lacking...
  • Astronomy Picture of the Day -- Bright Planets at McMath-Pierce Solar Telescope

    03/16/2012 12:18:41 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | March 16, 2012 | (see photo credit)
    Explanation: Bright planets Venus and Jupiter are framed by the National Solar Observatory's McMath-Pierce Solar Telescope in this very astronomical scene. The photo was taken at Kitt Peak National Observatory on March 9. A heliostat sits atop the 100 foot high solar telescope tower to focus the Sun's rays down a long diagonal shaft that reaches underground to the telescope's primary mirror. Of course, after sunset shadows were cast and the structure illuminated by light from the nearly full rising Moon. Opened to begin the night's work, the dome housing Kitt Peak's 2.1 meter reflector is included in the frame,...
  • Astronomy Picture of the Day -- Solar Flare in the Gamma-ray Sky

    03/14/2012 9:20:06 PM PDT · by SunkenCiv · 14 replies
    NASA ^ | March 15, 2012 | (see photo credit)
    Explanation: What shines in the gamma-ray sky? The answer is usually the most exotic and energetic of astrophysical environments, like active galaxies powered by supermassive black holes, or incredibly dense pulsars, the spinning remnants of exploded stars. But on March 7, a powerful solar flare, one of a series of recent solar eruptions, dominated the gamma-ray sky at energies up to 1 billion times the energy of visible light photons. These two panels illustrate the intensity of that solar flare in all-sky images recorded by the orbiting Fermi Gamma-ray Space Telescope. On March 6, as on most days, the Sun...
  • Astronomy Picture of the Day -- Angry Sun Erupting

    03/14/2012 3:31:13 PM PDT · by SunkenCiv · 6 replies
    NASA ^ | March 14, 2012 | (see photo credit)
    Explanation: It's one of the baddest sunspot regions in years. Active Region 1429 may not only look, to some, like an angry bird -- it has thrown off some of the most powerful flares and coronal mass ejections of the current solar cycle. The extended plumes from these explosions have even rained particles on the Earth's magnetosphere that have resulted in colorful auroras. Pictured above, AR 1429 was captured in great detail in the Sun's chromosphere three days ago by isolating a color of light emitted primarily by hydrogen. The resulting image is shown in inverted false color with dark...
  • Astronomy Picture of the Day -- The M81 Galaxy Group Through the Integrated Flux Nebula

    03/13/2012 3:58:05 AM PDT · by SunkenCiv · 6 replies
    NASA ^ | March 13, 2012 | (see photo credit)
    Explanation: Large galaxies and faint nebulae highlight this deep image of the M81 Group of galaxies. First and foremost in the wide-angle 12-hour exposure is the grand design spiral galaxy M81, the largest galaxy visible in the image. M81 is gravitationally interacting with M82 just below it, a big galaxy with an unusual halo of filamentary red-glowing gas. Around the image many other galaxies from the M81 Group of galaxies can be seen, as well as a lucky satellite glint streaking across the image left. Together with other galaxy congregates including our Local Group of galaxies and the Virgo Cluster...
  • Astronomy Picture of the Day -- The Scale of the Universe -- Interactive [Flash needed]

    03/11/2012 9:51:38 PM PDT · by SunkenCiv · 10 replies
    NASA ^ | March 12, 2012 | (see photo credit)
    Explanation: What does the universe look like on small scales? On large scales? Humanity is discovering that the universe is a very different place on every proportion that has been explored. For example, so far as we know, every tiny proton is exactly the same, but every huge galaxy is different. On more familiar scales, a small glass table top to a human is a vast plane of strange smoothness to a dust mite -- possibly speckled with cell boulders. Not all scale lengths are well explored -- what happens to the smallest mist droplets you sneeze, for example, is...
  • Astronomy Picture of the Day -- The Sombrero Galaxy in Infrared

    03/10/2012 9:39:16 PM PST · by SunkenCiv · 9 replies
    NASA ^ | March 11, 2012 | (see photo credit)
    Explanation: This floating ring is the size of a galaxy. In fact, it is part of the photogenic Sombrero Galaxy, one of the largest galaxies in the nearby Virgo Cluster of Galaxies. The dark band of dust that obscures the mid-section of the Sombrero Galaxy in optical light actually glows brightly in infrared light. The above image, digitally sharpened, shows the infrared glow, recently recorded by the orbiting Spitzer Space Telescope, superposed in false-color on an existing image taken by NASA's Hubble Space Telescope in optical light. The Sombrero Galaxy, also known as M104, spans about 50,000 light years across...
  • Astronomy Picture of the Day -- Lick Observatory Moonrise

    03/10/2012 9:36:43 AM PST · by SunkenCiv · 27 replies
    NASA ^ | March 10, 2012 | (see photo credit)
    Explanation: As viewed from a well chosen location at sunset, the gorgeous Full Moon rose behind Mount Hamilton, east of San Jose, California on March 7. The lunar disk frames historic Lick Observatory perched on the mountain's 4,200 foot summit. Both observatory and Moon echo the warm color of sunlight (moonlight is reflected sunlight) filtered by a long path through the atmosphere. Substantial atmospheric refraction contributes the Moon's ragged, green rim. Of course, the March Full Moon is also known as the Full Worm Moon. In the telescopic photo, Lick's 40 inch Nickel Telescope dome is on the left. The...
  • Astronomy Picture of the Day -- NGC 1579: Trifid of the North

    03/09/2012 4:35:28 AM PST · by SunkenCiv · 12 replies
    NASA ^ | March 09, 2012 | (see photo credit)
    Explanation: Colorful NGC 1579 resembles the better known Trifid Nebula, but lies much farther north in planet Earth's sky, in the heroic constellation Perseus. About 2,100 light-years away and 3 light-years across, NGC 1579 is, like the Trifid, a study in contrasting blue and red colors, with dark dust lanes prominent in the nebula's central regions. In both, dust reflects starlight to produce beautiful blue reflection nebulae. But unlike the Trifid, in NGC 1579 the reddish glow is not emission from clouds of glowing hydrogen gas excited by ultraviolet light from a nearby hot star. Instead, the dust in NGC...
  • Astronomy Picture of the Day -- The Seagull Nebula

    03/08/2012 3:00:48 PM PST · by SunkenCiv · 10 replies
    NASA ^ | March 08, 2012 | (see photo credit)
    Explanation: A broad expanse of glowing gas and dust presents a bird-like visage to astronomers from planet Earth, suggesting its popular moniker -- The Seagull Nebula. This portrait of the cosmic bird covers a 1.6 degree wide swath across the plane of the Milky Way, near the direction of Sirius, alpha star of the constellation Canis Major. Of course, the region includes objects with other catalog designations: notably NGC 2327, a compact, dusty emission region with an embedded massive star that forms the bird's head (aka the Parrot Nebula, above center). IC 2177 forms the sweeping arc of the seagull's...
  • Astronomy Picture of the Day -- Conjunction Over Reunion Island

    03/06/2012 9:15:48 PM PST · by SunkenCiv · 5 replies
    NASA ^ | March 06, 2012 | (see photo credit)
    Explanation: You don't have to be on Reunion Island to see this week's planetary conjunction. Only if you want to see this picturesque seascape as well. To see the conjunction from just about anywhere in the world, look to the west after sunset. The first planet you may notice is Venus, the brightest object in the western sky. Above Venus, the second brightest object is Jupiter. The hardest planet to spot is Mercury, which is visible only briefly after sunset as a faint dot just above the horizon. Picturesque rocks leading out from Reunion Island to the Indian Ocean populate...
  • Astronomy Picture of the Day -- NGC 2170: Celestial Still Life

    03/06/2012 9:10:12 PM PST · by SunkenCiv · 1 replies
    NASA ^ | March 06, 2012 | (see photo credit)
    Explanation: Is this a painting or a photograph? In this beautiful celestial still life composed with a cosmic brush, dusty nebula NGC 2170 shines near the image center. Reflecting the light of nearby hot stars, NGC 2170 is joined by other bluish reflection nebulae, a red emission region, many dark absorption nebulae, and a backdrop of colorful stars. Like the common household items still life painters often choose for their subjects, the clouds of gas, dust, and hot stars pictured above are also commonly found in this setting -- a massive, star-forming molecular cloud in the constellation of the Unicorn...
  • Astronomy Picture of the Day -- Flying Over the Earth at Night

    03/06/2012 9:06:45 PM PST · by SunkenCiv · 8 replies · 1+ views
    NASA ^ | March 05, 2012 | (see photo credit)
    Explanation: Many wonders are visible when flying over the Earth at night. A compilation of such visual spectacles was captured recently from the International Space Station (ISS) and set to rousing music. Passing below are white clouds, orange city lights, lightning flashes in thunderstorms, and dark blue seas. On the horizon is the golden haze of Earth's thin atmosphere, frequently decorated by dancing auroras as the video progresses. The green parts of auroras typically remain below the space station, but the station flies right through the red and purple auroral peaks. Solar panels of the ISS are seen around the...