Keyword: apod

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  • Astronomy Picture of the Day

    09/04/2008 4:11:02 AM PDT · by sig226 · 3 replies · 290+ views
    NASA ^ | 9/5/08 | Don Goldman
    Spokes in the Helix Nebula Credit & Copyright: Don Goldman, Sierra Remote Observatories Explanation: At first glance, the Helix Nebula (aka NGC 7293), looks simple and round. But this well-studied example of a planetary nebula, produced near the end of the life of a sun-like star, is now understood to have a surprisingly complex geometry. Its extended loops and comet-shaped features have been explored in Hubble Space Telescope images. Still, a 16-inch diameter telescope and camera with broad and narrow band filters was used to create this sharp view of the Helix. The color composite also reveals the nebula's...
  • Astronomy Picture of the Day

    09/03/2008 4:01:59 PM PDT · by sig226 · 7 replies · 318+ views
    NASA ^ | 9/4/08 | Donald J. Lindler, Sigma Space Corporation, GSFC, Univ. Maryland, EPOCh/DIXI Science Teams
    31 Million Miles from Planet Earth Video Credit: Donald J. Lindler, Sigma Space Corporation, GSFC, Univ. Maryland, EPOCh/DIXI Science Teams Explanation: On July 4th, 2005, the Deep Impact spacecraft directed a probe to impact the nucleus of Comet Tempel 1. Still cruising through the solar system, earlier this year the robotic spacecraft looked back to record a series of images of its home world 31 million miles (50 million kilometers) away. In a sequence from top left to bottom right, these four frames from the video show a rotating Earth. They combine visible and near-infrared image data with enough resolution...
  • Astronomy Picture of the Day

    09/02/2008 3:33:02 AM PDT · by sig226 · 2 replies · 362+ views
    NASA ^ | 9/2/08
    NGC 1316: After Galaxies Collide Credit & Copyright: Martin Pugh Explanation: Astronomers turn detectives when trying to figure out the cause of startling sights like NGC 1316. Their investigation indicates that NGC 1316 is an enormous elliptical galaxy that started, about 100 million years ago, to devour a smaller spiral galaxy neighbor, NGC 1317, just above it. Supporting evidence includes the dark dust lanes characteristic of a spiral galaxy, and faint swirls of stars and gas visible in this wide and deep image. What remains unexplained are the unusually small globular star clusters, seen as faint dots on the image....
  • Astronomy Picture of the Day

    09/01/2008 6:23:29 AM PDT · by sig226 · 6 replies · 428+ views
    NASA ^ | 9/1/08 | Mike Sidonio
    CG4: A Ruptured Cometary Globule Credit & Copyright: Mike Sidonio Explanation: Can a gas cloud grab a galaxy? It's not even close. The "claw" of this odd looking "creature" in the above photo is a gas cloud known as a cometary globule. This globule, however, has ruptured. Cometary globules are typically characterized by dusty heads and elongated tails. These features cause cometary globules to have visual similarities to comets, but in reality they are very much different. Globules are frequently the birthplaces of stars, and many show very young stars in their heads. The reason for the rupture in the...
  • Astronomy Picture of the Day

    08/31/2008 7:31:11 AM PDT · by sig226 · 4 replies · 413+ views
    NASA ^ | 8/31/08 | Mike Simmons
    Eclipse over the Great Wall Credit & Copyright: Mike Simmons (Astronomers Without Borders, TWAN) Explanation: Contrary to the famous myth, you can't see the Great Wall of China from the Moon ... even during a total solar eclipse. But on August 1 you could see the Moon eclipsing the Sun from the Great Wall. In fact, from this location near the Great Wall's western end, the Moon completely blocked the Sun's overwhelming disk revealing a shimmering solar corona and bright planets in the briefly darkened sky. A main pass, The Great Wall's Jiayuguan Fort, is also silhouetted in the...
  • Astronomy Picture of the Day

    08/29/2008 5:53:22 PM PDT · by sig226 · 4 replies · 335+ views
    NASA ^ | 8/29/08 | Lori Allen, Xavier Koenig
    Generations of Stars in W5 Credit: Lori Allen, Xavier Koenig (Harvard-Smithsonian CfA) et al., JPL-Caltech, NASA Explanation: Giant star forming region W5 is over 200 light-years across and about 6,500 light-years away in the constellation Cassiopeia. W5's sculpted clouds of cold gas and dust seem to form fantastic shapes in this impressive mosaic of infrared images from the Spitzer Space Telescope. In fact, the area on the right includes the structures previously dubbed the Mountains of Creation. New evidence indicates that successive generations of stars formed in the W5 region in an expanding pattern of triggered star formation. The older,...
  • Astronomy Picture of the Day

    08/28/2008 3:54:08 AM PDT · by sig226 · 1 replies · 369+ views
    NASA ^ | 8/28/08 | NASA
    Fermi's First Light Credit: NASA, DOE, International LAT Team Explanation: Launched on June 11 to explore the universe at extreme energies, the Gamma-ray Large Area Space Telescope has been officially renamed the Fermi Gamma-ray Space Telescope, in honor of Nobel Laureate Enrico Fermi (1901-1954), pioneer in high-energy physics. After testing, Fermi's two instruments, the Gamma-ray Burst Monitor (GBM) and the Large Area Telescope (LAT), are now regularly returning data. Fermi's first map of the gamma-ray sky from the LAT is shown in this false-color image, an all-sky view that looks toward the center of our Milky Way Galaxy with the...
  • Astronomy Picture of the Day

    08/27/2008 6:01:08 PM PDT · by sig226 · 6 replies · 396+ views
    NASA ^ | 8/27/08 | Ken Crawford
    IC 5146: The Cocoon Nebula Credit & Copyright: Ken Crawford (Rancho Del Sol Observatory) Explanation: Inside the Cocoon Nebula is a newly developing cluster of stars. Cataloged as IC 5146, the beautiful nebula is nearly 15 light-years wide, located some 4,000 light years away toward the northern constellation Cygnus. Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by young, hot stars and blue, dust-reflected starlight at the edge of an otherwise invisible molecular cloud. In fact, the bright star near the center of this nebula is likely only a few hundred thousand years old,...
  • Astronomy Picture of the Day

    08/24/2008 6:26:47 AM PDT · by sig226 · 9 replies · 526+ views
    NASA ^ | 8/24/08 | FORS1, 8.2-meter VLT Antu, ESO
    Grand Spiral Galaxy NGC 1232 Credit: FORS1, 8.2-meter VLT Antu, ESO Explanation: Galaxies are fascinating not only for what is visible, but for what is invisible. Grand spiral galaxy NGC 1232, captured in detail by one of the new Very Large Telescopes, is a good example. The visible is dominated by millions of bright stars and dark dust, caught up in a gravitational swirl of spiral arms rotating about the center. Open clusters containing bright blue stars can be seen sprinkled along these spiral arms, while dark lanes of dense interstellar dust can be seen sprinkled between them. Less visible,...
  • Astronomy Picture of the Day

    08/22/2008 4:41:24 PM PDT · by sig226 · 3 replies · 440+ views
    NASA ^ | 8/22/08 | NASA
    Regular ImageMouse - over ImageActive Galaxy NGC 1275 Credit: NASA, ESA, Hubble Heritage (STScI/AURA); A. Fabian (IoA, Cambridge U.), L. Frattare (STScI), CXC, G. Taylor, NRAO,VLA Explanation: Active galaxy NGC 1275 is the central, dominant member of the large and relatively nearby Perseus Cluster of Galaxies. A prodigious source of x-rays and radio emission, NGC 1275 accretes matter as entire galaxies fall into it, ultimately feeding a supermassive black hole at the galaxy's core. This stunning visible light image from the Hubble Space Telescope shows galactic debris and filaments of glowing gas, some up to 20,000 light-years long. The filaments...
  • Astronomy Picture of the Day

    08/19/2008 5:05:14 PM PDT · by sig226 · 11 replies · 540+ views
    NASA ^ | 8/19/08 | Adam Block
    NGC 6960: The Witch's Broom Nebula Credit & Copyright: Adam Block, Mount Lemmon SkyCenter, Univ. Arizona Explanation: Ten thousand years ago, before the dawn of recorded human history, a new light must suddenly have appeared in the night sky and faded after a few weeks. Today we know this light was an exploding star and record the colorful expanding cloud as the Veil Nebula. Pictured above is the west end of the Veil Nebula known technically as NGC 6960 but less formally as the Witch's Broom Nebula. The expanding debris cloud gains its colors by sweeping up and exciting existing...
  • Astronomy Picture of the Day

    08/18/2008 4:21:59 PM PDT · by sig226 · 10 replies · 475+ views
    NASA ^ | 8/18/08 | Leonid Durman
    Baily's Beads near Solar Eclipse Totality Credit & Copyright: Leonid Durman Explanation: Just before the Sun blacks out, something strange occurs. As the Moon moves to completely cover the Sun in a total solar eclipse, beads of bright sunlight stream around the edge of the Moon. This effect, known as Baily's beads, is named after Francis Baily who called attention to the phenomenon in 1836. Although, the number and brightness of Baily's beads used to be unpredictable, today the Moon is so well mapped that general features regarding Baily's beads are expected. When a single bead dominates, it is...
  • Astronomy Picture of the Day

    08/17/2008 7:41:09 AM PDT · by sig226 · 7 replies · 558+ views
    NASA ^ | 8/17/08 | NASA
    Io's Surface: Under Construction Credit: Galileo Project, JPL, NASA Explanation: Like the downtown area of your favorite city, the roads you drive to work on, 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...
  • Astronomy Picture of the Day

    08/15/2008 5:18:45 PM PDT · by sig226 · 8 replies · 577+ views
    NASA ^ | 8/15/08
    CopyrightedFacing NGC 6946 Credit & Copyright: Volker Wendel (Spiegelteam) Explanation: From our vantage point in the Milky Way Galaxy, we see NGC 6946 face-on. The big, beautiful spiral galaxy is located just 10 million light-years away, behind a veil of foreground dust and stars in the high and far-off constellation of Cepheus. From the core outward, the galaxy's colors change from the yellowish light of old stars in the center to young blue star clusters and reddish star forming regions along the loose, fragmented spiral arms. NGC 6946 is also bright in infrared light and rich in gas and dust,...
  • Astronomy Picture of the Day

    08/14/2008 3:56:35 PM PDT · by sig226 · 1 replies · 368+ views
    NASA ^ | 8/14/08 | Wally Pacholka
    Perseid Trail Credit & Copyright: Wally Pacholka (Astropics.com / TWAN) Explanation: This bright and colorful meteor flashed through Tuesday's early morning skies, part of the annual Perseid Meteor Shower. The lovely image is one of over 350 frames captured on August 12 from the Joshua Tree National Park, in California, USA . Dust from comet Swift-Tuttle is responsible for the Perseids, creating the northern hemisphere's regular summer sky show. The comet dust is vaporized as it enters the atmosphere at upwards of 60 kilometers per second, producing visible trails that begin at altitudes of around 100 kilometers. Of course, the...
  • Astronomy Picture of the Day

    08/13/2008 5:02:00 PM PDT · by sig226 · 6 replies · 480+ views
    NASA ^ | 8/13/08 | Tony Hallas
    NGC 6888: The Crescent Nebula Credit & Copyright: Tony Hallas Explanation: NGC 6888, also known as the Crescent Nebula, is a cosmic bubble about 25 light-years across, blown by winds from its central, bright, massive star. This beautiful telescopic view combines a composite color image with narrow band data that isolates light from hydrogen and oxygen atoms in the wind-blown nebula. The oxygen atoms produce the blue-green hue that seems to enshroud the detailed folds and filaments. NGC 6888's central star is classified as a Wolf-Rayet star (WR 136). The star is shedding its outer envelope in a strong stellar...
  • Astronomy Picture of the Day

    08/11/2008 3:45:06 AM PDT · by sig226 · 5 replies · 490+ views
    NASA ^ | 8/11/08 | ESA, Hubble
    Black Hole Candidate Cygnus X-1 Credit: ESA, Hubble Explanation: Is that a black hole? Quite possibly. The Cygnus X-1 binary star system contains one of the best candidates for a black hole. The system was discovered because it is one of the brightest X-ray sources on the sky, shining so bright it was detected by the earliest rockets carrying cameras capable of seeing the previously unknown X-ray sky. The star's very name indicates that it is the single brightest X-ray source in the constellation of the Swan Cygnus. Data indicate that a compact object there contains about nine times...
  • Astronomy Picture of the Day

    08/09/2008 5:19:54 AM PDT · by sig226 · 3 replies · 424+ views
    NASA ^ | 8/9/08 | Jimmy Westlake
    Aurora Persei Credit & Copyright: Jimmy Westlake (Colorado Mountain College) Explanation: Dark skies are favored for viewing meteor showers -- so the best viewing of this year's Perseids will occur in the early morning. While the Perseid meteor shower is scheduled to peak over the next few days, bright light from a gibbous Moon will also flood the early evening and mask the majority of relatively faint meteors. Still, skygazing in the early morning after the Moon sets (after about 2 AM local time) could reveal spectacular earthgrazing meteors. Persisting observing at any time after sunset can reward northern...
  • Astronomy Picture of the Day

    08/08/2008 4:00:49 PM PDT · by sig226 · 5 replies · 425+ views
    NASA ^ | 8/8/08 | Hartwig Luethen
    The Crown of the Sun Credit & Copyright: Hartwig Luethen Explanation: During a total solar eclipse, the Sun's extensive outer atmosphere, or corona, is an inspirational sight. The subtle shades and shimmering features of the corona that engage the eye span a brightness range of over 10,000 to 1, making them notoriously difficult to capture in a single picture. But this composite of 28 digital images ranging in exposure time from 1/1000 to 2 seconds comes close to revealing the crown of the Sun in all its glory. The telescopic views were recorded near Kochenevo, Russia during the August...
  • Astronomy Picture of the Day

    08/07/2008 3:35:23 AM PDT · by sig226 · 13 replies · 611+ views
    NASA ^ | 8/7/08 | Catalin Beldea
    At the Sun's Edge Credit & Copyright: Catalin Beldea (Descopera Magazine) Explanation: A train trip on the Trans-Siberian railway to Novosibirsk resulted in this stunning view along the edge of the Sun recorded during the August 1st total solar eclipse. The picture is a composite of two images taken at special moments in the eclipse sequence, corresponding to the very beginning and the very end of the total eclipse phase. Those times are known to eclipse chasers as 2nd and 3rd contact. Bright beads around the Moon's dark silhouette are rays of sunlight shining through lunar valleys at the edge...
  • Astronomy Picture of the Day

    08/06/2008 3:24:45 PM PDT · by sig226 · 3 replies · 381+ views
    NASA ^ | 8/6/08 | Diedre Hunter
    NGC 1818: A Young Globular Cluster Credit: Diedre Hunter (Lowell Obs.) et al., HST, NASA Explanation: Globular clusters once ruled the Milky Way. Back in the old days, back when our Galaxy first formed, perhaps thousands of globular clusters roamed our Galaxy. Today, there are perhaps 200 left. Many globular clusters were destroyed over the eons by repeated fateful encounters with each other or the Galactic center. Surviving relics are older than any Earth fossil, older than any other structures in our Galaxy, and limit the universe itself in raw age. There are few, if any, young globular clusters in...
  • Astronomy Picture of the Day

    08/04/2008 7:26:24 PM PDT · by sig226 · 19 replies · 671+ views
    NASA ^ | 8/4/08 | NASA
    X-Rays from the Cat's Eye Nebula Credit: X-ray: NASA/CXC/SAO; Optical: NASA/STScI Explanation: Haunting patterns within planetary nebula NGC 6543 readily suggest its popular moniker -- the Cat's Eye nebula. Starting in 1995, stunning false-color optical images from the Hubble Space Telescope detailed the swirls of this glowing nebula, known to be the gaseous shroud expelled from a dying sun-like star about 3,000 light-years from Earth. This composite picture combines the latest Hubble optical image of the Cat's Eye with new x-ray data from the orbiting Chandra Observatory and reveals surprisingly intense x-ray emission indicating the presence of extremely hot gas....
  • Astronomy Picture of the Day

    08/03/2008 7:27:36 AM PDT · by sig226 · 4 replies · 493+ views
    NASA ^ | 8/3/08 | NASA, ESA, E. Olszewski
    Open Cluster NGC 290: A Stellar Jewel Box Credit: ESA & NASA; Acknowledgement: E. Olszewski (U. Arizona) Explanation: Jewels don't shine this bright -- only stars do. Like gems in a jewel box, though, the stars of open cluster NGC 290 glitter in a beautiful display of brightness and color. The photogenic cluster, pictured above, was captured recently by the orbiting Hubble Space Telescope. Open clusters of stars are younger, contain few stars, and contain a much higher fraction of blue stars than do globular clusters of stars. NGC 290 lies about 200,000 light-years distant in a neighboring galaxy...
  • Astronomy Picture of the Day

    08/02/2008 5:55:43 AM PDT · by sig226 · 6 replies · 510+ views
    NASA ^ | 8/2/08 | Philippe Haake
    Eclipse Shirt Credit & Copyright: Philippe Haake Explanation: Of course, everyone is concerned about what to wear to a solar eclipse. No need to worry though, nature often conspires to project images of the eclipse so that stylish and appropriate patterns adorn many visible surfaces - including clothing - at just the right time. Most commonly, small gaps between leaves on trees can act as pinhole cameras and generate multiple recognizable images of the eclipse. In Madrid to view the 2005 October 3rd annular eclipse of the Sun, astronomer Philippe Haake met a friend who had another inspiration. The result,...
  • Astronomy Picture of the Day

    08/01/2008 2:59:42 PM PDT · by sig226 · 4 replies · 427+ views
    NASA ^ | 8/1/08 | Laurent Laveder
    Moon Games Credit & Copyright: Laurent Laveder (PixHeaven.net / TWAN) Explanation: The Moon's measured diameter is around 3,476 kilometers (2,160 miles). But apparent angular size, or the angle covered by an object, can also be important to Moon enthusiasts. Angular size depends on distance, the farther away an object is, the smaller an angle it covers. Since the Moon is 400,000 kilometers away, its angular size is only about 1/2 degree, a span easily covered by the tip of your finger held at arms length, or a measuring tape held in the distance by a friend. Of course the Sun...
  • Astronomy Picture of the Day

    07/31/2008 12:52:11 PM PDT · by sig226 · 5 replies · 521+ views
    NASA ^ | 7/31//08 | Acquisition - Martin Winder, Processing - Warren Keller
    Galaxies on a String Credit & Copyright: Acquisition - Martin Winder, Processing - Warren Keller Galaxies NGC 5216 (top right) and NGC 5218 really do look like they are connected by a string. Of course, that string is a cosmic trail of gas, dust, and stars about 22,000 light-years long. Also known as Keenan's system (for its discoverer) and Arp 104, the interacting galaxy pair is some 17 million light-years away in the constellation Ursa Major. The debris trail that joins them, along with NGC 5218's comma-shaped extension and the distorted arms of NGC 5216 are a consequence of mutual...
  • Astronomy Picture of the Day

    07/29/2008 2:43:35 PM PDT · by sig226 · 9 replies · 582+ views
    NASA | 7/29/08 | Kerry-Ann Lecky Hepburn
    The Milky Way Over Ontario Credit & Copyright: Kerry-Ann Lecky Hepburn (Weather and Sky Photography) Explanation: Sometimes, after your eyes adapt to the dark, a spectacular sky appears. Such was the case earlier this month over Ontario, Canada, when part of a spectacular sky also became visible in a reflection off a lake. To start, the brightest objects visible are bright stars and the planet Jupiter, seen as the brightest spot on the upper left. A distant town appears as a diffuse glow over the horizon. More faint still, the disk of the Milky Way Galaxy becomes apparent as...
  • Astronomy Picture of the Day

    07/28/2008 2:23:07 PM PDT · by sig226 · 2 replies · 491+ views
    NASA ^ | 7/28/08 | A. Bolton
    SDSSJ1430: A Galaxy Einstein Ring Credit: A. Bolton (UH/IfA) for SLACS and NASA/ESA Explanation: What's large and blue and can wrap itself around an entire galaxy? A gravitational lens mirage. Pictured above on the left, the gravity of a normal white galaxy has gravitationally distorted the light from a much more distant blue galaxy. More normally, such light bending results in two discernable images of the distant galaxy, but here the lens alignment is so precise that the background galaxy is distorted into a nearly complete ring. Since such a lensing effect was generally predicted in some detail by Albert...
  • Astronomy Picture of the Day

    07/27/2008 7:38:55 AM PDT · by sig226 · 9 replies · 594+ views
    NASA ^ | 7/27/08 | C. R. O'Dell
    IC 4406: A Seemingly Square Nebula Credit: C. R. O'Dell (Vanderbilt U.) et al., Hubble Heritage Team, NASA Explanation: How can a round star make a square nebula? This conundrum comes to light when studying planetary nebulae like IC 4406. Evidence indicates that IC 4406 is likely a hollow cylinder, with its square appearance the result of our vantage point in viewing the cylinder from the side. Were IC 4406 viewed from the top, it would likely look similar to the Ring Nebula. This representative-color picture is a composite made by combining images taken by the Hubble Space Telescope...
  • Astronomy Picture of the Day

    07/26/2008 4:59:00 AM PDT · by sig226 · 5 replies · 470+ views
    NASA ^ | 7/26/08 | Keith Quattrocchi
    Central IC 1805 Credit & Copyright: Keith Quattrocchi Explanation: Cosmic clouds seem to form fantastic shapes in the central regions of emission nebula IC 1805. Of course, the clouds are sculpted by stellar winds and radiation from massive hot stars in the nebula's newborn star cluster (aka Melotte 15). About 1.5 million years young, the cluster stars appear on the right in this colorful skyscape, along with dark dust clouds silhouetted against glowing atomic gas. A composite of narrow and broad band telescopic images, the view spans about 15 light-years and includes emission from hydrogen in green, sulfur in red,...
  • Astronomy Picture of the Day

    07/25/2008 1:10:58 PM PDT · by sig226 · 9 replies · 538+ views
    NASA ^ | 7/25/08 | NASA, JPL-Caltech, K. Gordon (STScI) et al.
    Spitzer's M101 Credit: NASA, JPL-Caltech, K. Gordon (STScI) et al. Explanation: Big, beautiful spiral galaxy M101 is one of the last entries in Charles Messier's famous catalog, but definitely not one of the least. About 170,000 light-years across, this galaxy is enormous, almost twice the size of our own Milky Way Galaxy. M101 was also one of the original spiral nebulae observed by Lord Rosse's large 19th century telescope, the Leviathan of Parsontown. Recorded at infrared wavelengths by the Spitzer Space telescope, this 21st century view shows starlight in blue hues while the galaxy's dust clouds are in red....
  • Astronomy Picture of the Day

    07/24/2008 2:35:00 PM PDT · by sig226 · 20 replies · 583+ views
    NASA ^ | 7/14/08 | NASA
    When Storms Collide Credit: NASA, ESA, Amy Simon-Miller (Goddard Space Flight Center), N. Chanover (NMSU), G. Orton (JPL) Four posts before someone says, "Bush's fault." :) Explanation: These detailed Hubble Space Telescope close-ups feature Jupiter's ancient swirling storm system known as the Great Red Spot. They also follow the progress of two newer storm systems that have grown to take on a similar reddish hue: the smaller "Red Spot Jr." (bottom), and smaller still, a "baby red spot". Red Spot Jr. was seen to form in 2006, while the smaller spot was just identified earlier this year. For scale, the...
  • Astronomy Picture of the Day

    07/23/2008 2:34:18 PM PDT · by sig226 · 7 replies · 580+ views
    NASA ^ | 7/23/08 | G. Neukum
    High Cliffs Surrounding Echus Chasma on Mars Credit: G. Neukum (FU Berlin) et al., Mars Express, DLR, ESA Explanation: What created this great cliff on Mars? Did giant waterfalls once plummet through its grooves? With a four-kilometer drop, this high cliff surrounding Echus Chasma, near an impressive impact crater, was carved by either water or lava. A leading hypothesis is that Echus Chasma, at 100-kilometers long and 10-kilometers wide, was once one of the largest water sources on Mars. If true, water once held in Echus Chasma likely ran over the Martian surface to carve the impressive Kasei Valles, which...
  • Astronomy Picture of the Day

    07/22/2008 3:01:19 PM PDT · by sig226 · 20 replies · 613+ views
    NASA ^ | 7/21/08 | Gemini Observatory, GMOS-South, NSF
    The Colliding Spiral Galaxies of Arp 271 Credit & Copyright: Gemini Observatory, GMOS-South, NSF Explanation: What will become of these galaxies? Spiral galaxies NGC 5426 and NGC 5427 are passing dangerously close to each other, but each is likely to survive this collision. Most frequently when galaxies collide, a large galaxy eats a much smaller galaxy. In this case, however, the two galaxies are quite similar, each being a sprawling spiral with expansive arms and a compact core. As the galaxies advance over the next tens of millions of years, their component stars are unlikely to collide, although new stars...
  • Astronomy Picture of the Day

    07/20/2008 6:30:13 AM PDT · by sig226 · 5 replies · 590+ views
    NASA ^ | 7/20/08 | NASA
    Crescent Rhea Occults Crescent Saturn Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA Explanation: Soft hues, partially lit orbs, a thin trace of the ring, and slight shadows highlight this understated view of the majestic surroundings of the giant planet Saturn. Looking nearly back toward the Sun, the robot Cassini spacecraft now orbiting Saturn captured crescent phases of Saturn and its moon Rhea in color a few years ago. As striking as the above image is, it is but a single frame from a recently released 60-frame silent movie where Rhea can be seen gliding in front of its parent...
  • Astronomy Picture of the Day

    07/19/2008 5:56:24 AM PDT · by sig226 · 5 replies · 512+ views
    NASA ^ | 7/219/08 | Johannes Schedler (Panther Observatory)
    M16 and the Eagle Nebula Credit & Copyright: Johannes Schedler (Panther Observatory) Explanation: Young star cluster M16 is surrounded by natal clouds of cosmic dust and glowing gas also known as The Eagle Nebula. This beautifully detailed image of the region includes fantastic shapes made famous in well-known Hubble Space Telescope close-ups of the starforming complex. Described as elephant trunks or Pillars of Creation, dense, dusty columns rising near the center are light-years in length but are gravitationally contracting to form stars. Energetic radiation from the cluster stars erodes material near the tips, eventually exposing the embedded new stars. Extending...
  • Astronomy Picture of the Day

    07/16/2008 3:15:01 PM PDT · by sig226 · 14 replies · 589+ views
    NASA ^ | 7/16/08 | R. Hurt (SSC-Caltech)
    Makemake of the Outer Solar System Credit: R. Hurt (SSC-Caltech), JPL-Caltech, NASA Explanation: Recently discovered Makemake is one of the largest objects known in the outer Solar System. Pronounced MAH-kay MAH-kay, this Kuiper belt object is only slightly smaller than Pluto, orbits the Sun only slightly further out than Pluto, and appears only slightly dimmer than Pluto. Makemake, however, has an orbit much more tilted to the ecliptic plane of the planets than Pluto. Designated 2005 FY9 soon after its discovery by a team led by Mike Brown (Caltech) in 2005, the outer Solar System orb was recently renamed Makemake...
  • Astronomy Picture of the Day

    07/14/2008 2:41:13 PM PDT · by sig226 · 8 replies · 552+ views
    NASA ^ | 7/14/08 | Richard Bosman
    Changes in Angular Mars Credit & Copyright: Richard Bosman ,b>Explanation: Does Mars always appear the same? No. As both Earth and Mars orbit the Sun, the apparent angular size of Mars changes as viewed from the Earth. Pictured above from Enschede, Holland, Mars was captured in 2007 and 2008 with 30 separate images, all taken with the same magnification. When Earth and Mars are on opposite sides of the Sun, Mars appears relatively small. Conversely, when Earth and Mars are near each other, Mars looms large and bright. The largest Mars has appeared in recent history was the opposition of...
  • Astronomy Picture of the Day

    07/12/2008 5:45:46 AM PDT · by sig226 · 9 replies · 579+ views
    NASA ^ | 7/12/08 | Don Goldman
    NGC 7331 and Beyond Credit & Copyright: Don Goldman, Sierra Remote Observatories Explanation: Big, beautiful spiral galaxy NGC 7331 is often touted as an analog to our own Milky Way. About 50 million light-years distant in the northern constellation Pegasus, NGC 7331 was recognized early on as a spiral nebula and is actually one of the brighter galaxies not included in Charles Messier's famous 18th century catalog. Since the galaxy's disk is inclined to our line-of-sight, long telescopic exposures often result in an image that evokes a strong sense of depth. The effect is further enhanced in this well-framed view...
  • Astronomy Picture of the Day

    07/11/2008 3:36:36 PM PDT · by sig226 · 28 replies · 850+ views
    NASA ^ | 7/11/08 | R. Hurt (SSC)
    The Far 3kpc Arm Illustration Credit: R. Hurt (SSC), JPL-Caltech, NASA Explanation: A major discovery was lurking in the data. By accident, while preparing a talk on the Galaxy's spiral arms for a meeting of the American Astronomical Society, Tom Dame (Harvard-Smithsonian CfA) found it - a new spiral arm in the Milky Way. The arm is labeled in this illustration as the Far 3kpc Arm, located at a distance of 3 kpc (kiloparsecs) or about 10,000 light-years from the galactic center, on the opposite side from the Sun. Along with the Near 3kpc Arm whose presence was known since...
  • Astronomy Picture of the Day

    07/08/2008 2:08:45 PM PDT · by sig226 · 10 replies · 631+ views
    NASA ^ | 7/8/-08 | Günter Kerschhuber
    In the Heart of the Virgo Cluster Credit & Copyright: Günter Kerschhuber (Gahberg Observatory) Explanation: The Virgo Cluster of Galaxies is the closest cluster of galaxies to our Milky Way Galaxy. The Virgo Cluster is so close that it spans more than 5 degrees on the sky - about 10 times the angle made by a full Moon. With its heart lying about 70 million light years distant, the Virgo Cluster is the nearest cluster of galaxies, contains over 2,000 galaxies, and has a noticeable gravitational pull on the galaxies of the Local Group of Galaxies surrounding our Milky...
  • Astronomy Picture of the Day

    07/07/2008 4:40:51 PM PDT · by sig226 · 3 replies · 555+ views
    NASA ^ | 7/7/08 | Yuri Beletsky
    The Southern Cross in a Southern Sky Credit & Copyright: Yuri Beletsky (ESO) Explanation: This breathtaking patch of sky would be above you were you to stand at the South Pole of the Earth. On the upper left of this image are the four stars that mark the boundaries of the famous Southern Cross. At the top of this constellation, also known as The Crux, is the orange star Gamma Crucis. The band of stars, dust, and gas crossing the middle of the photograph is part our Milky Way Galaxy. Just below the Southern Cross on the far left is...
  • Astronomy Picture of the Day

    07/05/2008 4:22:29 AM PDT · by sig226 · 3 replies · 504+ views
    NASA ^ | 7/5/08 | Antti Kemppainen
    Comet Between Fireworks and Lightning Credit & Copyright: Antti Kemppainen Explanation: Sometimes the sky itself is the best show in town. Last January, people from Perth, Australia gathered on a local beach to watch a sky light up with delights near and far. Nearby, fireworks exploded as part of Australia Day celebrations. On the far right, lightning from a thunderstorm flashed in the distance. Near the image center, though, seen through clouds, was the most unusual sight of all: Comet McNaught. The photogenic comet was so bright that it even remained visible though the din of Earthly flashes. Comet McNaught...
  • Astronomy Picture of the Day

    07/04/2008 5:46:20 AM PDT · by sig226 · 16 replies · 585+ views
    NASA ^ | 7/4/08 | Everybody
    SN 1006 Supernova Remnant Credit: X-ray - NASA/CXC/Rutgers/G.Cassam-Chenai, J.Hughes et al.; Radio - NRAO/AUI/NSF/GBT/VLA/ Dyer, Maddalena & Cornwell; Optical - Middlebury College/F.Winkler, NOAO/AURA/NSF/CTIO Schmidt & DSS Explanation: A new star, likely the brightest supernova in recorded human history, lit up planet Earth's sky in the year 1006 AD. The expanding debris cloud from the stellar explosion, found in the southerly constellation of Lupus, still puts on a cosmic light show across the electromagnetic spectrum. In fact, this composite view includes X-ray data in blue from the Chandra Observatory, optical data in yellowish hues, and radio image data in red....
  • Astronomy Picture of the Day

    07/02/2008 2:35:19 PM PDT · by sig226 · 9 replies · 576+ views
    NASA ^ | T. Rector, H. Schweiker
    Pickering's Triangle from Kitt Peak Credit & Copyright: T. Rector (U. Alaska Anchorage), H. Schweiker, WIYN, NOAO, AURA, NSF Explanation: Wisps like this are all that remain visible of a Milky Way star. About 7,500 years ago that star exploded in a supernova leaving the Veil Nebula, also known as the Cygnus Loop. At the time, the expanding cloud was likely as bright as a crescent Moon, remaining visible for weeks to people living at the dawn of recorded history. Today, the resulting supernova remnant has faded and is now visible only through a small telescope directed toward the constellation...
  • Astronomy Picture of the Day

    06/30/2008 2:28:12 PM PDT · by sig226 · 8 replies · 648+ views
    NASA ^ | 6/30/08 | Daniel Lopez (Observatorio del Teide)
    In the Center of the Trifid Nebula Credit & Copyright: Daniel Lopez (Observatorio del Teide) Explanation: Clouds of glowing gas mingle with dust lanes in the Trifid Nebula, a star forming region toward the constellation of Sagittarius. In the center, the three prominent dust lanes that give the Trifid its name all come together. Mountains of opaque dust appear on the right, while other dark filaments of dust are visible threaded throughout the nebula. A single massive star visible near the center causes much of the Trifid's glow. The Trifid, also known as M20, is only about 300,000 years old,...
  • Some classic Astronomy Picture of the Day images

    06/28/2008 6:13:43 AM PDT · by ETL · 10 replies · 635+ views
    Astronomy Picture of the Day (APOD) | various dates | NASA
    Here are a few past APODs (Astronomy Picture of the Day) that I've collected over the years. They really are incredible. However, some make take awhile to download, especially if you're on dial-up. Hope you enjoy them... Orion Spitzer:http://antwrp.gsfc.nasa.gov/apod/image/0608/orion_spitzer_f.jpg NGC-2174:http://antwrp.gsfc.nasa.gov/apod/image/0612/NGC2174_lrg.jpg M-42:http://antwrp.gsfc.nasa.gov/apod/image/0601/m42_hst_f.jpg Orion Cradle:http://antwrp.gsfc.nasa.gov/apod/image/0701/orioncradle_hallas_r.jpg Wisps Surrounding the Horsehead Nebula:http://antwrp.gsfc.nasa.gov/apod/ap080406.html Markarian's Eyes:http://antwrp.gsfc.nasa.gov/apod/image/0706/NGC4438_NGC4435_crawford_r.jpg Carina Nebula Panorama from Hubble:http://antwrp.gsfc.nasa.gov/apod/image/0704/carina_hst_big.jpg Bullet Pillars in Orion:http://antwrp.gsfc.nasa.gov/apod/image/0703/bullets_gemini_big.jpg The Rosette Nebula:http://antwrp.gsfc.nasa.gov/apod/image/0702/rosette_gendler_big.jpg For individual descriptions of these images, go to the APOD archive page and run a search on the selected image's title:http://antwrp.gsfc.nasa.gov/apod/archivepix.html
  • Astronomy Picture of the Day

    06/28/2008 5:37:30 AM PDT · by sig226 · 5 replies · 494+ views
    NASA ^ | 6/28/08 | Joseph Brimacombe
    Fireball at Ayers Rock Credit & Copyright: Joseph Brimacombe Explanation: A weekend trip for astrophotography in central Australia can result in gorgeous skyscapes. In this example recorded in March of 2006, the center of our Milky Way Galaxy rises over planet Earth's horizon and the large sandstone formation called Uluru, also known as Ayers Rock. After setting up two cameras to automatically image this celestial scene in a series of exposures, one through a wide-angle and the other through a telephoto lens, photographer Joseph Brimacombe briefly turned his back to set up other equipment. To his surprise, the ground around...
  • Astronomy Picture of the Day

    06/25/2008 2:22:36 PM PDT · by sig226 · 20 replies · 738+ views
    NASA ^ | 6/25/08 | Galaxy Zoo Project, ING
    What is Hanny's Voorwerp? Credit: Galaxy Zoo Project, ING Explanation: What is that green thing? A volunteer sky enthusiast surfing through online Galaxy Zoo images has discovered something really strange. The mystery object is unusually green, not of any clear galaxy type, and situated below relatively normal looking spiral galaxy IC 2497. Dutch schoolteacher Hanny van Arkel, discovered the strange green "voorwerp" (Dutch for "object") last year. The Galaxy Zoo project encourages sky enthusiasts to browse through SDSS images and classify galaxy types. Now known popularly as Hanny's Voorwerp, subsequent observations have shown that the mysterious green blob has the...
  • Astronomy Picture of the Day

    06/24/2008 2:27:26 PM PDT · by sig226 · 9 replies · 689+ views
    NASA ^ | 6/24/08 | NASA
    Ithaca Chasma: The Great Rift on Saturn's Tethys Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA Explanation: What created the Great Rift on Saturn's moon Tethys? No one is sure. More formally named Ithaca Chasma, the long canyon running across the right of the above image extends about 2,000 kilometers long and spreads as much as 100 kilometers wide. The above image was captured by the Saturn-orbiting robotic Cassini spacecraft as it zoomed by the icy moon last month. Hypotheses for the formation of Ithaca Chasma include cracking of Tethy's outer crust as the moon cooled long ago, and that...