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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...

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...

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...

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...

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...

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....

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...

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,...

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

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...

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...

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...

Barred Spiral Galaxy NGC 1300 Credit: Hubble Heritage Team, ESA, NASA 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...

Vanishing Act Phoenix Mission Team, NASA, JPL-Caltech, U. Arizona, Texas A&M University Explanation: Compare these two close-up pictures taken on sol 20 (left) and sol 24 of a trench dug in the Martian surface by NASA's Phoenix Lander. Those sols of the Phoenix Mission (a sol is a Martian day), correspond to June 15 and 18 on planet Earth. Light-colored, dice-sized chunks, visible in the lower left shadow region of the trench in the sol 20 image have vanished by sol 24 -- a strong indication that the chunks were ice uncovered by digging the shallow trench. The vanishing act...

Solstice Moonrise, Cape Sounion Credit & Copyright: Anthony Ayiomamitis (TWAN) Explanation: Today's solstice marks the northernmost point of the Sun's annual motion through planet Earth's sky and the astronomical beginning of the northern hemisphere's summer. But only two days ago, the Full Moon nearest the solstice rose close to the ecliptic plane opposite the Sun, near its southernmost point for the year. Astronomer Anthony Ayiomamitis recorded this dramatic picture of the solstice Full Moon rising above Cape Sounion, Greece. The twenty-four hundred year old Temple of Poseidon lies in the foreground, also visible to sailors on the Aegean Sea. In...

Pyramid Ice Crystal Halos Over Finland Credit & Copyright: Kari Nyman Explanation: What if the atmosphere above you became one gigantic lens? This actually happens when a nearly transparent sheet of pyramid shaped ice crystals falls from the sky in a common orientation. These ice-crystals act together like millions of miniature ice mirrors, with external and internal reflections from different faces creating arcs and halos of different radii. An amazing display of pyramid ice crystal halos was captured on June 5 above Tampere, Finland. Visible above are very unusual sun halos of 9, 18, 20, 23, and 24 degrees. In...

Eta Carinae and the Homunculus Nebula Credit: N. Smith, J. A. Morse (U. Colorado) et al., NASA Explanation: How did the star Eta Carinae create this unusual nebula? No one knows for sure. About 165 years ago, the southern star Eta Carinae mysteriously became the second brightest star in the night sky. In 20 years, after ejecting more mass than our Sun, Eta Car unexpected faded. This outburst appears to have created the Homunculus Nebula, pictured above in a composite image from the Hubble Space Telescope taken last decade. Visible in the above image center is purple-tinted light reflected from...

Inside the Coma Cluster of Galaxies Credit: NASA, ESA, Hubble Heritage (STScI/AURA); Acknowledgment: D. Carter (LJMU) et al. and the Coma HST ACS Treasury Team Explanation: Almost every object in the above photograph is a galaxy. The Coma Cluster of Galaxies pictured above is one of the densest clusters known - it contains thousands of galaxies. Each of these galaxies houses billions of stars - just as our own Milky Way Galaxy does. Although nearby when compared to most other clusters, light from the Coma Cluster still takes hundreds of millions of years to reach us. In fact, the...

At Last, GLAST Image Credit: Jerry Cannon, Robert Murray, NASA Explanation: Rising through a billowing cloud of smoke, this Delta II rocket left Cape Canaveral Air Force Station's launch pad 17-B Wednesday at 12:05 pm EDT. Snug in the payload section was GLAST, the Gamma-ray Large Area Space Telescope, now in orbit around planet Earth. GLAST's detector technology was developed for use in terrestrial particle accelerators. But from orbit, GLAST can study gamma-rays from extreme environments in our own Milky Way galaxy, as well as supermassive black holes at the centers of distant active galaxies, and the sources of...

Dextre Robot at Work on the Space Station Credit: STS-124 Crew, Expedition 17 Crew, NASA Explanation: What's the world's most complex space robot doing up there? Last week, Dextre was imaged moving atop the Destiny Laboratory Module of the International Space Station (ISS), completing tasks prior to the deployment of Japan's Kibo pressurized science laboratory. Dextre, short for the Canadian-built Special Purpose Dextrous Manipulator, has arms three meters in length and can attach power tools as fingers. Behind Dextre is the blackness of space, while Earth looms over Dextre's head. The Kibo laboratory segment being deployed during space shuttle Discovery's...