Astronomy Picture of the Day

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2010 May 18

Tentacles of the Tarantula Nebula
Credit: ESO; Acknowledgments: J. Alves (Calar Alto), B. Vandame, and Y. Beletsky (ESO); Processing by B. Fosbury (ST-ECF)

Explanation: The largest, most violent star forming region known in the whole Local Group of galaxies lies in our neighboring galaxy the Large Magellanic Cloud (LMC). Were the Tarantula Nebula at the distance of the Orion Nebula -- a local star forming region -- it would take up fully half the sky. Also called 30 Doradus, the red and pink gas indicates a massive emission nebula, although supernova remnants and dark nebula also exist there. The bright knot of stars left of center is called R136 and contains many of the most massive, hottest, and brightest stars known. The above image taken with the European Southern Observatory's (ESO's) Wide Field Imager is one of the most detailed ever of this vast star forming region. A recent Hubble image of part of the nebula has uncovered a very massive star escaping from the region.

Tomorrow's picture: ghost sky

Take Care All!

 

[monza]

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2010 May 12

M72: A Globular Cluster of Stars
Credit: NASA, ESA, Hubble, HPOW

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 less than 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 our Milky Way Galaxy because conditions are not ripe for more to form. Pictured above by the Hubble Space Telescope are about 100,000 of M72's stars. M72, which spans about 50 light years and lies about 50,000 light years away, can be seen with a small telescope toward the constellation of the Water Bearer (Aquarius).

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[monza]

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2010 May 16

Crescent Venus and Moon
Credit & Copyright: Iván Éder

Explanation: There's something behind these clouds. Those faint graceful arcs, upon inspection, are actually far, far in the distance. They are the Earth's Moon and the planet Venus. Both the Moon and Venus are bright enough to be seen during the day, and both are quite capable of showing a crescent phase. To see Venus, which appears quite small, in a crescent phase requires binoculars or a telescope. In the above dramatic daytime image taken from Budapest, Hungary in 2004, the Moon and Venus shared a similar crescent phase a few minutes before the Moon eclipsed the larger but more distant world. Similarly, visible today in parts of Africa and Asia, a crescent Moon will again eclipse Venus during the day. About an hour after the above image was taken, Venus reappeared.

Tomorrow's picture: sky whale

Take Care All!

 

[monza]

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2010 May 18

Tentacles of the Tarantula Nebula
Credit: ESO; Acknowledgments: J. Alves (Calar Alto), B. Vandame, and Y. Beletsky (ESO); Processing by B. Fosbury (ST-ECF)

Explanation: The largest, most violent star forming region known in the whole Local Group of galaxies lies in our neighboring galaxy the Large Magellanic Cloud (LMC). Were the Tarantula Nebula at the distance of the Orion Nebula -- a local star forming region -- it would take up fully half the sky. Also called 30 Doradus, the red and pink gas indicates a massive emission nebula, although supernova remnants and dark nebula also exist there. The bright knot of stars left of center is called R136 and contains many of the most massive, hottest, and brightest stars known. The above image taken with the European Southern Observatory's (ESO's) Wide Field Imager is one of the most detailed ever of this vast star forming region. A recent Hubble image of part of the nebula has uncovered a very massive star escaping from the region.

Tomorrow's picture: ghost sky

Take Care All!

 

[monza]

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2010 May 19

Milky Way Over Ancient Ghost Panel
Credit & Copyright: Bret Webster Explanation: Long before Stonehenge was built, well before the Dead Sea Scrolls were written, ancient artists painted life-sized figures on canyon walls in Utah, USA -- but why? Nobody is sure. The entire panel of figures, which dates back about 7,000 years, is called the Great Gallery and was found on the walls of Horseshoe Canyon in Canyonlands National Park. The humans who painted them likely hunted Mammoths. The unusual fuzziness of largest figure led to this mural section's informal designation as the Holy Ghost Panel, although the intended attribution and societal importance of the figure are really unknown. The above image was taken during a clear night in March. The oldest objects in the above image are not the pictographs, however, but the stars of our Milky Way Galaxy far in the background, some of which are billions of years old.

 

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2010 May 20

M87: Elliptical Galaxy with Jet
Image Credit & Copyright: Adam Block, Mt. Lemmon SkyCenter, U. Arizona

Explanation: In spiral galaxies, majestic winding arms of young stars, gas, and dust rotate in a flat disk around a bulging galactic nucleus. But elliptical galaxies seem to be simpler. Lacking gas and dust to form new stars, their randomly swarming older stars, give them an ellipsoidal (egg-like) shape. Still, elliptical galaxies can be very large. Centered in this telescopic view and over 120,000 light-years in diameter, larger than our own Milky Way, elliptical galaxy M87 (NGC 4486) is the dominant galaxy of the Virgo Galaxy Cluster. Some 50 million light-years away, M87 is likely home to a supermassive black hole responsible for a high-energy jet of particles emerging from the giant galaxy's central region. In this well-processed image, M87's jet is near the one o'clock position. Other galaxies are also in the field of view, including large Virgo Cluster ellipticals NGC 4478 right of center and NGC 4476 near the right edge.

Tomorrow's picture: skyviewr

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[poopoy]

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2010 May 21

Calm, Cresent Moon, and Venus
Image Credit & Copyright: P-M Hedén (Clear Skies, TWAN)

Explanation: Last weekend, the Moon and Venus formed a beautiful close pair in the west after sunset, a scene enjoyed by skygazers all over the world. In this lovely view of the conjunction from Sweden, a calm lake Vallentuna lies in the foreground with sunset colors still fading behind the treeline on the far shore. The young Moon's sunlit crescent is bright, but its entire outline can be seen by Earthshine, light reflected from planet Earth itself. For well-placed skygazers, on Sunday, May 16 the Moon actually occulted (passed in front of) brilliant Venus. For many, the occultation was visible during daylight hours.

Tomorrow's picture: sunny Saturdayr

Take Care All!

 

[monza]

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2010 May 23

Station and Shuttle Transit the Sun
Credit & Copyright: Thierry Legault Explanation: That's no sunspot. On the upper right of the above image of the Sun, the dark patches are actually the International Space Station (ISS) and the Space Shuttle Atlantis on mission STS-132. In the past, many skygazers have spotted the space station and space shuttles as bright stars gliding through twilight skies, still glinting in the sunlight while orbiting about 350 kilometers above the Earth's surface. But here, astrophotographer Thierry Lagault accurately computed the occurrence of a rarer opportunity to record the spacefaring combination moving quickly in silhouette across the solar disk. He snapped the above picture on last Sunday on May 16, about 50 minutes before the shuttle docked with the space station. Atlantis was recently launched to the ISS for its last mission before being retired.

 

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2010 May 24

Rho Ophiuchi Wide Field
Credit & Copyright: Rogelio Bernal Andreo Explanation: The clouds surrounding the star system Rho Ophiuchi compose one of the closest star forming regions. Rho Ophiuchi itself is a binary star system visible in the light-colored region on the image right. The star system, located only 400 light years away, is distinguished by its colorful surroundings, which include a red emission nebula and numerous light and dark brown dust lanes. Near the upper right of the Rho Ophiuchi molecular cloud system is the yellow star Antares, while a distant but coincidently-superposed globular cluster of stars, M4, is visible between Antares and the red emission nebula. Near the image bottom lies IC 4592, the Blue Horsehead nebula. The blue glow that surrounds the Blue Horsehead's eye -- and other stars around the image -- is a reflection nebula composed of fine dust. On the above image left is a geometrically angled reflection nebula cataloged as Sharpless 1. Here, the bright star near the dust vortex creates the light of surrounding reflection nebula. Although most of these features are visible through a small telescope pointed toward the constellations of Ophiuchus, Scorpius, and Sagittarius, the only way to see the intricate details of the dust swirls, as featured above, is to use a long exposure camera.

 

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2010 May 25

Looking Back Across Mars
Credit: Mars Exploration Rover Mission, JPL, NASA Explanation: It's been a long trip for the Martian rover Opportunity. Last week Opportunity surpassed Viking 1 as the longest running mission on Mars, now extending well over six years. Pictured above, Opportunity's tire tracks cross a nearly featureless Martian desert, emanating from a distant horizon. Landing in 2004 in Meridiani Planum, the robotic Opportunity has embarked on its longest and most dangerous trek yet, now aiming to reach large Endeavor Crater sometime next year. Endeavor, it is hoped, holds new clues to the ancient geology of Mars and whether Mars could once have harbored life.

 

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2010 May 26

Clouds and Stars over Cotopaxi Volcano in Ecuador
Credit & Copyright: Stéphane Guisard (Los Cielos de America), TWAN Explanation: What's happening above the Cotopaxi volcano in Ecuador? Quite a bit, from the looks of the above one-night, time-lapse movie, taken earlier this month. The majestic volcano is first seen through breaks in fast moving clouds as the movie begins. Soon the clouds have dissipated and a sky filled with stars seems to rotate about the snow-peaked volcano's peak. The band of our Milky Way Galaxy, the dark Coal Sack nebula, and the Southern Cross can all be seen overhead. Satellites steak by from several directions. Soon thin clouds roll by and seem to make the brightest stars sparkle. On the volcano (starting at about 1:13 of the movie), the lights of climbers flash. Near the end of the movie, a bright airplane passes over the peak with a residual trail seen drifting away.

 

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2010 May 27

M13: The Great Globular Cluster in Hercules
Image Credit & Copyright: Marco Burali, Tiziano Capecchi, Marco Mancini (Osservatorio MTM) Explanation: In 1716, English astronomer Edmond Halley noted, "This is but a little Patch, but it shews itself to the naked Eye, when the Sky is serene and the Moon absent." Of course, M13 is now modestly recognized as the Great Globular Cluster in Hercules, one of the brightest globular star clusters in the northern sky. Telescopic views reveal the spectacular cluster's hundreds of thousands of stars. At a distance of 25,000 light-years, the cluster stars crowd into a region 150 light-years in diameter, but approaching the cluster core upwards of 100 stars could be contained in a cube just 3 light-years on a side. For comparison, the closest star to the Sun is over 4 light-years away. Along with the cluster's dense core, the outer reaches of M13 are highlighted in this sharp color image. The cluster's evolved red and blue giant stars show up in yellowish and blue tints.

 

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2010 May 28

Atlantis over Rhodes
Image Credit & Copyright: Tamas Ladanyi (TWAN) Explanation: A moonlit chapel stands in the foreground of this night-scape from the historic Greek island of Rhodes. The tantalizing sky above features a colorful lunar corona, where bright moonlight is diffracted by water droplets in the thin clouds drifting in front of the lunar disk. Captured in the early evening on May 17, the image is a composite of 9 exposures in sequence, each 20 seconds long. It shows star trails too, including the very bright trail of planet Venus setting, below the Moon, near the right edge of the frame. Arcing from the horizon on the right to the picture's left edge is a surprisingly colorful trail produced by space shuttle orbiter Atlantis docked with the International Space Station. Some 350 kilometers above Earth's surface, the orbiter and station pair are still bathed in sunlight. Though it might seem more appropriate when seen in skies over Rhodes, the shuttle orbiter Atlantis wasn't directly named for the legendary island of Atlantis. Instead, it was named for 1930s vintage sailing ship RV Atlantis, the first research vessel operated by the Woods Hole Oceanographic Institute.

Tomorrow's picture: merging galaxies, supermassive black holes

 

[monza]

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2010 May 29

Black Holes in Merging Galaxies
Credit: NASA / Swift / NOAO / Michael Koss and Richard Mushotzky (Univ. Maryland) Explanation: Violent galaxy mergers can feed supermassive black holes. Theoretically, the result is intense emission from regions near the supermassive black holes, creating the some of the most luminous objects in the universe. Astronomers dub these Active Galactic Nuclei, or just AGN. But for decades only about 1 percent of AGN seemed to be associated with galaxy mergers. New results from a premier sky survey by NASA's Swift satellite at hard (energetic) X-ray energies now solidly show a strong association of AGN with merging galaxies, though. The hard X-rays more readily penetrate dust and gas clouds in merging galaxies and reveal the presence of emission from the active black holes. In fact, these panels show the location (circled) of Swift X-ray detected supermassive black holes in a variety of merging galaxy systems. The optical images are from the Kitt Peak National Observatory in Arizona. At top center is NGC 7319 and the compact galaxy group known as Stephan's Quintet.

 

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2010 May 30

The Galactic Center in Infrared from 2MASS
Credit: 2MASS Project, U. Mass., IPAC/Caltech, NSF, NASA Explanation: The center of our Galaxy is a busy place. In visible light, much of the Galactic Center is obscured by opaque dust. In infrared light, however, dust glows more and obscures less, allowing nearly one million stars to be recorded in the above image. The Galactic Center itself appears glowing on the lower left and is located about 30,000 light years away towards the constellation of Sagittarius. The Galactic Plane of our Milky Way Galaxy, the plane in which the Sun orbits, is identifiable by the dark diagonal dust lane. The absorbing dust grains are created in the atmospheres of cool red-giant stars and grow in molecular clouds. The region directly surrounding the Galactic Center glows brightly in radio and high-energy radiation. The Galactic Center is thought to house a large black hole.

 

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2010 May 31

Moons and Rings Before Saturn
Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA Explanation: While cruising around Saturn, be on the lookout for picturesque juxtapositions of moons and rings. Another striking alignment occurred last March in the view of humanity's Saturn-orbiting Cassini spacecraft. Rhea, one of Saturn's larger moons, was caught passing Epimetheus, one of Saturn's smaller moons. Epimetheus, as pictured above, is actually well behind the heavily cratered Rhea. Further back, several of the complex rings of Saturn can be seen crossing the image horizontally. Behind both the moons and rings is giant Saturn itself, showing expansive but featureless clouds in the green light where the above image was taken. The Cassini mission around Saturn has now been extended to 2017 to better study the complex planetary system as its season changes from equinox to solstice.




http://www.sat-universe.com/redirector.php?url=http://apod.nasa.gov/apod/ap100601.html

 

[monza]

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2010 June 1

WISE: Heart and Soul Nebulas in Infrared
Credit: NASA, JPL-Caltech, WISE Team Explanation: Is the heart and soul of our Galaxy located in Cassiopeia? Possibly not, but that is where two bright emission nebulas nicknamed Heart and Soul can be found. The Heart Nebula, officially dubbed IC 1805 and visible in the above right, has a shape in optical light reminiscent of a classical heart symbol. The above image, however, was taken in infrared light by the recently launched WISE telescope. Infrared light penetrates well inside the vast and complex bubbles created by newly formed stars in the interior of these two massive star forming regions. Studies of stars and dust like those found in the Heart and Soul Nebulas have focussed on how massive stars form and how they affect their environment. Light takes about 6,000 years to reach us from these nebulas, which together span roughly 300 light years.

 

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2010 June 2

A Twisted Meteor Trail Over Tenerife
Credit & Copyright: Juergen Rendtel (AIP Potsdam), IMO Explanation: Did this meteor take a twisting path? No one is sure. Considered opinions are solicited. Meteors, usually sand sized grains that originate in comets, will typically disintegrate as they enter the Earth's atmosphere. A fast moving meteor ionizes molecules in the Earth's atmosphere that subsequently glow when they reacquire electrons. Meteor paths that twist noticeably have been noted before, and even photographed, but attributing such behavior to the motion of the meteor itself and neither the wind-blown meteor train nor the observer remains somewhat controversial. The above meteor, imaged two weeks ago streaking over the Teide Observatory in Tenerife, Canary Islands, appears to swagger as much as several minutes of arc, which the experienced astrophotographer did not think could be attributed to drifting of the resulting train or motion of the camera mount. If truly an indication of a twisted meteor path, an underlying reason could be the pictured meteor was markedly non-spherical in shape, non-uniform in composition, or electrically charged. Non-uniform meteors, for example, may evaporate more on one side than another, causing a rotating meteor to wobble. Understanding meteors is important partly because meteors are candidates to have seeded Earth with prebiotic molecules that allowed for the development of life.

 

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2010 June 3

Jupiter from the Stratosphere
Credit: Infrared - NASA, USRA, DSI, Cornell Univ. / Visible - Anthony Wesley Explanation: SOFIA, the Stratospheric Observatory for Infrared Astronomy, captured its "first light" images on May 26, from an altitude of 35,000 feet. While flying above most of planet Earth's infrared-absorbing water vapor, SOFIA's premier infrared views of the cosmos included this remarkable false-color image (right panel) of Jupiter. For comparison, on the left is a recent, ground-based visible light image. Both show our solar system's ruling gas giant without its dark southern equatorial belt (normally seen in the upper hemisphere in this orientation). That familiar feature faded from view early in May. But the bright white stripe in SOFIA's image is a region of Jupiter's clouds transparent to infrared light, offering a glimpse below the cloud tops.

 

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Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2010 June 4

Hubble Remix: Active Galaxy NGC 1275
Credit: Data - Hubble Legacy Archive, ESA, NASA; Processing - Al Kelly Explanation: Active galaxy NGC 1275 is the central, dominant member of the large and relatively nearby Perseus Cluster of Galaxies. Wild-looking at visible wavelengths, the active galaxy is also a prodigious source of x-rays and radio emission. NGC 1275 accretes matter as entire galaxies fall into it, ultimately feeding a supermassive black hole at the galaxy's core. This color composite image, recreated from archival Hubble Space Telescope data, highlights the resulting galactic debris and filaments of glowing gas, some up to 20,000 light-years long. The filaments persist in NGC 1275, even though the turmoil of galactic collisions should destroy them. What keeps the filaments together? Observations indicate that the structures, pushed out from the galaxy's center by the black hole's activity, are held together by magnetic fields. Also known as Perseus A, NGC 1275 spans over 100,000 light years and lies about 230 million light years away.