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Scattered debris from a cosmic supernova explosion lights up the sky in this gorgeous composited image based on data from the Hubble Space Telescope. Cataloged as N49, these glowing filaments of shocked gas span about 30 light-years in our neighboring galaxy, the Large Magellanic Cloud. Light from the original exploding star reached Earth thousands of years ago, but N49 also marks the location of another energetic outburst -- an extremely intense blast of gamma-rays detected by satellites on March 5, 1979. That date was the beginning of an exciting journey in astrophysics which led researchers to the understanding of an exotic new class of stars. The source of the "March 5th Event" is now attributed to a magnetar - a highly magnetized, spinning neutron star also born in the ancient stellar explosion which created supernova remnant N49. The magnetar hurtles through the supernova debris cloud at over 1,200 kilometers per second. Photo Credit: Hubble Heritage Team (STScI / AURA), Y. Chu (UIUC) et al., NASA


This photograph of the coil-shaped Helix Nebula is one of the largest and most detailed celestial images ever made. The composite picture is a seamless blend of ultra-sharp images from NASA's Hubble Space Telescope combined with the wide view of the Mosaic Camera on the National Science Foundation's 0.9-meter telescope at Kitt Peak National Observatory near Tucson, Ariz. The image shows a fine web of filamentary "bicycle-spoke" features embedded in the colorful red and blue ring of gas. At 650 light-years away, the Helix is one of the nearest planetary nebulae to Earth. A planetary nebula is the glowing gas around a dying, Sun-like star. Credit: NASA, NOAO, ESA, the Hubble Helix Nebula Team, M. Meixner (STScI), and T.A. Rector (NRAO).


In 1764, French astronomer Charles Messier sighted this gorgeous cosmic cloud which he described as an oval nebula without stars. Cataloged as M27, it is now popularly known as the Dumbbell Nebula, not for its substandard academic performance but for the elongated shape, like a bar with weights on each end, which first caught Messier's eye. This deep image of the bright planetary nebula does reveal the Dumbell's central star though, and an array of foreground and background stars toward the sly constellation Vulpecula. The picture is a composite that includes 8 hours of exposure through a filter designed to record only the light of hydrogen atoms, tracing the intricate details of the nebula's faint outer halo which spans light-years. Thought to be an example of the fate awaiting our own Sun 5 billion years hence, the Dumbbell Nebula is about 1,200 light-years away. Photo Credit & Copyright: Robert Gendler


One of the most identifiable nebulae in the sky, the Horsehead Nebula in Orion, is part of a large, dark, molecular cloud. Also known as Barnard 33, the unusual shape was first discovered on a photographic plate in the late 1800s. The red glow originates from hydrogen gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis. The darkness of the Horsehead is caused mostly by thick dust, although the lower part of the Horsehead's neck casts a shadow to the left. Streams of gas leaving the nebula are funneled by a strong magnetic field. Bright spots in the Horsehead Nebula's base are young stars just in the process of forming. Light takes about 1500 years to reach us from the Horsehead Nebula. The above image was taken with the 0.9-meter telescope at Kitt Peak National Observatory. Photo Credit & Copyright: Nigel Sharp (NOAO), KPNO, AURA, NSF



Even a quiet Sun is a busy place. The above image, taken in a single color of light called Hydrogen Alpha, records a great amount of detail of the simmering surface of our parent star. The gradual darkening towards the Sun's edge, called limb darkening, is caused by increased absorption of relatively cool solar gas. Further over the edge, a giant prominence is visible, while a different prominence can be seen in silhouette as the dark streak near the image center. Two active areas of the Sun are marked by bright plages. The above amateur photograph of the Sun was taken just last month through a small telescope and a standard digital camera. In contrast, there are times when our Sun appears much more active. Photo Credit & Copyright: Ralph Encarnacion


NASA's Hubble Space Telescope took this close-up of the red planet Mars when it was just 34,648,840 miles (55,760,220 km) away. This color image was assembled from a series of exposures taken between 6:20 p.m. and 7:12 p.m. EDT Aug. 26 with Hubble's Wide Field and Planetary Camera 2. The picture was taken just 11 hours before the planet made its closest approach to Earth in 60,000 years.


The largest canyon in the Solar System cuts a wide swath across the face of Mars. Named Valles Marineris, the grand valley extends over 3,000 kilometers long, spans as much as 600 kilometers across, and delves as much as 8 kilometers deep. By comparison, the Earth's Grand Canyon in Arizona, USA is 800 kilometers long, 30 kilometers across, and 1.8 kilometers deep. The origin of the Valles Marineris remains unknown, although a leading hypothesis holds that it started as a crack billions of years ago as the planet cooled. Recently, several geologic processes have been identified in the canyon. The above mosaic was created from over 100 images of Mars taken by Viking Orbiters in the 1970s. Photo Credit: Viking Project,



Its core hidden from optical view by a thick lane of dust, the giant elliptical galaxy Centaurus A was among the first objects observed by the orbiting Chandra X-ray Observatory. Astronomers were not disappointed, as Centaurus A's appearance in x-rays makes its classification as an active galaxy easy to appreciate. Perhaps the most striking feature of this Chandra false-color x-ray view is the jet, 30,000 light-years long. Blasting toward the upper left corner of the picture, the jet seems to arise from the galaxy's bright central x-ray source -- suspected of harboring a black hole with a million or so times the mass of the Sun. Centaurus A is also seen to be teeming with other individual x-ray sources and a pervasive, diffuse x-ray glow. Most of these individual sources are likely to be neutron stars or solar mass black holes accreting material from their less exotic binary companion stars. The diffuse high-energy glow represents gas throughout the galaxy heated to temperatures of millions of degrees C. At 11 million light-years distant in the constellation Centaurus, Centaurus A (NGC 5128) is the closest active galaxy. Photo Credit: R.Kraft (SAO) et al., CXO, NASA


Dramatic prominences can sometimes be seen looming just beyond the edge of the sun. A solar prominence is a cloud of solar gas held just above the surface by the Sun's magnetic field. The Earth would easily fit below the prominence on the left. A quiescent prominence typically lasts about a month, and may erupt in a Coronal Mass Ejection (CME) expelling hot gas into the Solar System. Although very hot, prominences typically appear dark when viewed against the Sun, since they are slightly cooler than the surface. The above image in false color was taken on June 1 from Stuttgart, Germany with an amateur telescope and camera. Photo Credit & Copyright: Stefan Seip (AstroMeeting)


Waves of clouds along the east flanks of the Andes Mountains cast off an orange glow by the low angle of the sun in the West. The dark area to the left is the Earth's terminator. This view was photographed by astronaut Frank Borman and James A. Lovell during the Gemini 7 mission, looking South from Northern Bolivia across the Andes. The Intermontane Salt Basins are visible in the background. Photo Credit: NASA



How smooth is the Sun? The new Swedish 1-m Solar Telescope, deployed in the Canary Islands only last year, allows imaging of objects less than 100-km across on the Sun's surface. When pointed toward the Sun's edge, surface objects now begin to block each other, indicating true three-dimensional information. Close inspection of the image reveals much vertical information, including spectacular light-bridges rising nearly 500-km above the floor of sunspots near the top of the image. Also visible in the above false-color image are hundreds of bubbling granules, each about 1000-km across, and small bright regions known as faculas. Photo Credit: G. Scharmer (ISP, RSAS) et al., Lockheed-Martin Solar & Astrophysics Lab.


The Earth's northern hemisphere is outlined as a sunlit crescent in this dramatic view from orbit, recorded near local midnight by the Geostationary Operational Environmental Satellite (GOES-8) on June 22, 1996. That date was two days after the Solstice, by astronomical reckoning, the first day of summer in the north and winter in the southern hemisphere. Today's scheduled geocentric astronomical event is again the northern hemisphere's summer Solstice, with the Sun reaching its northernmost declination at 19 hours 10 minutes Universal Time. That makes today also the longest day of the year in the north, with the arctic regions near the top of the picture experiencing 24 hours of daylight. Looking south along the Earth's limb, atmospheric scattering of sunlight causes the limb to be visible beyond areas directly illuminated by the sun. Credit: GOES Project, GSFC, NASA


Two of NASA's Great Observatories, bolstered by the largest ground-based telescopes around the world, are beginning to harvest new clues to the origin and evolution of the universe's largest building block, the galaxies. It's a bit like finding a family scrapbook containing snapshots that capture the lives of family members from infancy through adolescence to adulthood. Credit: NASA, ESA, the Goods Team and M. Giavalisco (STScI)


This image, showing what looks to be a human face sculpted on the martian surface, was produced using data from NASA's Viking 1 orbiter in 1976. Described in a press release as a "face-like hill" it caused some to offer the sensational speculation that it was an artificial construct built by an intelligent civilization on Mars! As a result, this image was splashed across the covers of many grocery store tabloids at the time. A detailed analysis of multiple images of this feature reveals a natural looking martian hill whose illusory face-like appearance depends on viewing angle and angle of illumination. Picture Credit: NASA,Viking Project.


The first APOD appeared eight years ago today, on 1995 June 16. To date, we estimate that APOD has now served over 100 million space-related images. We again thank our readers and NASA for their continued support, but ask that any potentially congratulatory e-mail go to the folks who created the great pictures -- many times with considerable effort -- that APOD has been fortunate enough to feature over the past year. Many can be contacted by following links found in the credit line under the image. Some of these images are featured in the above spectacular collage submitted by an enthusiastic APOD reader well skilled in digital image manipulation. She challenges fellow APODees to find in the collage her favorite ex-member of the musical group Tangerine Dream. Credit & Copyright: Elana Kestrel (Dreamcircle)

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