Astronomy fanatica
-
Astronomy Picture of the Day
2006 January 21
Apollo 12: Self-Portrait
Explanation: In November of 1969, Apollo 12 astronaut-photographer Charles "Pete" Conrad recorded this masterpiece while documenting colleague Alan Bean's lunar soil collection activities on the Oceanus Procellarum. The image is dramatic and stark. The harsh environment of the Moon's Ocean of Storms is echoed in Bean's helmet, a perfectly composed reflection of Conrad and the lunar horizon. Is it art? Works of photojournalists originally intent on recording the human condition on planet Earth, such as Lewis W. Hine's images from New York City in the early 20th century, or Margaret Bourke-White's magazine photography are widely regarded as art. Similarly many documentary astronomy and space images can be appreciated for their artistic and esthetic appeal.
Credit: Charles Conrad, Apollo 12, NASA -
Astronomy Picture of the Day
2006 January 22
D. rad Bacteria: Candidate Astronauts
Explanation: These bacteria could survive on another planet. In an Earth lab, Deinococcus radiodurans (D. rad) survive extreme levels of radiation, extreme temperatures, dehydration, and exposure to genotoxic chemicals. Amazingly, they even have the ability to repair their own DNA, usually with 48 hours. Known as an extremophile, bacteria such as D. rad are of interest to NASA partly because they might be adaptable to help human astronauts survive on other worlds. A recent map of D. rad's DNA might allow biologists to augment their survival skills with the ability to produce medicine, clean water, and oxygen. Already they have been genetically engineered to help clean up spills of toxic mercury. Likely one of the oldest surviving life forms, D. rad was discovered by accident in the 1950s when scientists investigating food preservation techniques could not easily kill it. Pictured above, Deinococcus radiodurans grow quietly in a dish.
Credit: Michael Daly (Uniformed Services University of the Health Sciences), DOE -
Astronomy Picture of the Day
2006 January 23
The LMC Galaxy in Glowing Gas
Explanation: What goes on inside of a galaxy? To help find out, astronomers from the Magellanic Cloud Emission Line Survey team imaged our neighboring LMC galaxy in spectacular detail and highlighted very specific colors of light emitted by glowing gas. The above mosaic of over 1,500 images of the Large Magellanic Cloud (LMC) is the result -- clicking on the image will bring up an image with much greater detail. The colors highlighted on the mosaic are light emitted by hydrogen (red), oxygen (green), and sulfur (yellow), while light from individual stars has been subtracted. The mosaic shows what a busy and violent place the inside of the LMC really is. Visible in the above image are many small planetary nebulas pushed out by low mass stars, large emission nebula of ambient interstellar gas set aglow by massive stars, and huge gaseous supernova remnants cast off by massive stars exploding. The extended connected filaments are mostly connected supernova remnants. The LMC, a familiar sight to an unaided eye in the southern hemisphere, spans about 15,000 light years and lies only about 180,000 light years distant.
Credit: C. Smith, S. Points, the MCELS Team and NOAO/AURA/NSF -
Astronomy Picture of the Day
2006 January 24
New Horizons Launches to Pluto
Explanation: Destination: Pluto. The New Horizons spacecraft roared off its launch pad at Cape Canaveral in Florida, USA last week toward adventures in the distant Solar System. The craft is one of the fastest spaceships ever launched by humans, having passed the Moon only nine hours after launch and is on track to buzz Jupiter in early 2007. Even traveling over 75,000 kilometers per hour, the New Horizons craft will not arrive at Pluto until 2015. Pluto is the only remaining planet that has never been visited by a spacecraft or photographed up close. After Pluto, the robot spaceship will visit one or more Kuiper Belt Objects orbiting the Sun even further out than Pluto. Pictured, the New Horizons craft launches into space atop a powerful Atlas V rocket.
Image Credit & Copyright: Ben Cooper -
Astronomy Picture of the Day
2006 January 25
The Expanding Light Echoes of SN 1987A
Explanation: Can you find supernova 1987A? It isn't hard -- it occurred at the center of the expanding bullseye pattern. Although this stellar detonation was first seen almost two decades ago, light from it continues to bounce off clumps of interstellar dust and be reflected to us today. These expanding light echoes have been recorded in the above time-lapse movie recorded over four years from the Blanco 4-meter telescope in Chile. The first image is an image of the SN 1987A region, while the next four images were created by subtracting consecutive images, taken a year apart, and leaving only the difference between the images. Light echoes can be seen moving out from the position of the supernova. The SuperMACHO team who recorded the above light echoes around supernova 1987A has also found faint and previously unnoticed light echoes from two other LMC supernovas. Study of these light echoes has enabled more accurate determinations of the location and date of these two supernova explosions that were first visible hundreds of years ago.
Credit: The SuperMACHO Team, CTIO, NOAO, NSF -
Astronomy Picture of the Day
2006 January 26
An Unusual Two-Toned Rock on Mars
Explanation: How did this unusual Martian rock form? The atypical two-toned rock, visible in the lower right of the above image, was photographed a few days ago by the robotic Spirit rover currently rolling across Mars. For now, the environmental processes that created the rock remain a matter of speculation. Finding unusual rocks is not unusual for Spirit or its twin rover Opportunity, however. Over the past two years, for example, the rovers have unexpectedly discovered very small gray pebbles dubbed blueberries, and a rock out in the middle of nowhere now thought to be a meteorite. Having investigated alien terrain and having found clear evidence that part of Mars had a wet past, the Earth-launched Martian rovers are now entering their third spectacular year exploring the red planet.
Credit: Mars Exploration Rover Mission, Cornell, JPL, NASA -
Astronomy Picture of the Day
2006 January 27
A New Storm on Saturn
Explanation: Presently at opposition in planet Earth's sky, Saturn is well placed for telescopic observations. On Wednesday two amateur astronomers took full advantage of the situation from Melun, near Paris, France. With a 12 inch diameter telescope and web cam they recorded this sharp image of the ringed gas giant and made an exciting discovery -- a new storm on Saturn. The storm appears as the white spot visible here in Saturn's southern hemisphere (south is toward the top in the picture). In particular, the storm seems to correspond with an outburst of radio noise detected by the Cassini spacecraft. The phenomenon is likely similar to the Dragon Storm recorded by Cassini's instruments early last year. That storm is thought to be analogous to a terrestrial thunderstorm, with radio noise produced in high-voltage lightning discharges.
Credit & Copyright: Jean-Luc Dauvergne, Erick Bondoux -
Astronomy Picture of the Day
2006 January 28
Saturn in the Hive
Explanation: If you can find Saturn in tonight's sky, then you can also find M44, popularly known as the Beehive star cluster. In fact, with a pair of binoculars most casual skygazers should find it fairly easy to zero in on this celestial scene. Saturn is at opposition - opposite the Sun in Earth's sky - so, the bright planet rises in the east at sunset and is visible throughout the night. Near the stationary part of its wandering path through the heavens, Saturn will obligingly linger for a while in the vicinity of M44 in the relatively faint constellation Cancer. Seen here in a photograph from January 25, Saturn (lower right) is strongly overexposed with the stars of M44 swarming above and to the left. The picture approximately corresponds to the view when looking through a typical pair of binoculars. Saturn is about 64 light-minutes from our fair planet while M44, one of the closest star clusters, is around 600 light-years away.
Credit & Copyright: Jimmy Westlake (Colorado Mountain College) -
Astronomy Picture of the Day
2006 January 29
Volcano and Aurora in Iceland
Explanation: Sometimes both heaven and Earth erupt. In Iceland in 1991, the volcano Hekla erupted at the same time that auroras were visible overhead. Hekla, one of the most famous volcanoes in the world, has erupted at least 20 times over the past millennium, sometimes causing great destruction. The last eruption occurred only six years ago but caused only minor damage. The green auroral band occurred fortuitously about 100 kilometers above the erupting lava. Is Earth the Solar System's only planet with both auroras and volcanos?
Credit: Sigurdur H. Stefnisson -
Astronomy Picture of the Day
2006 January 30
NGC 1999: South of Orion
Explanation: South of the large star-forming region known as the Orion Nebula, lies bright blue reflection nebula NGC 1999. The nebula is marked with a dark inverted T-shape at the lower left in a broad cosmic vista that spans over 10 light-years. The dark shape is a dense gas and dust cloud, or Bok globule, seen in silhouette against the bright nebula, and likely a site of future star formation. At the edge of the Orion molecular cloud complex some 1,500 light-years distant, NGC 1999's illumination is provided by the embedded variable star V380 Orionis. The region abounds with energetic young stars producing jets and outflows that create luminous shock waves, including HH (Herbig-Haro) 1 and 2 just below and left of NGC 1999, and the apparent cascade of reddish arcs and bow shocks beginning at the upper right. The stellar jets and outflows push through the surrounding material at speeds of hundreds of kilometers per second.
Credit & Copyright: Robert Gendler -
Astronomy Picture of the Day
2006 January 31
Huygens on Titan Illustrated
Explanation: If you could stand on Titan, what might you see? About one year ago the robotic Huygens probe landed on the enigmatic moon of Saturn and sent back the first ever images from beneath Titan's thick cloud layers. From the images sent back, an artist's impression of Huygens on Titan's surface has been reconstructed. In the foreground of the above image sits the car-sized lander that sent back images for more than 90 minutes before running out of battery power. The parachute that slowed Huygen's re-entry is seen in the background, attached to the lander by strong cords. Strange light smooth stones possibly containing water-ice are visible surrounding the landing craft. Analyses of Huygen's images and data shows that Titan's surface today has intriguing similarities to the surface of the early Earth.
Illustration Credit: ESA -
Astronomy Picture of the Day
2006 February 1
Venus Just After Sunset
Explanation: Is that Venus or an airplane? A common ponderable for sky enthusiasts is deciding if that bright spot near the horizon is the planet Venus. Usually, an airplane will show itself by moving significantly in a few moments. Venus will set only slowly as the Earth turns. Still, the identification would be easier if Venus did not keep shifting its position each night. Pictured above, Venus was captured 38 different nights during 2005 and 2006 over Bursa, Turkey, when Earth's sister planet appeared exclusively in the evening sky. The average spacing of the images was about five days, while the images were always taken with the Sun about 7 degrees below the horizon. Venus' orbit around the Sun will now confine it to Earth's morning sky until October 2006.
Credit & Copyright: Tunç Tezel -
Astronomy Picture of the Day
2006 February 2
Thor's Helmet in H-Alpha
Explanation: Near picture center, the helmet-shaped structure with wing-like appendages is popularly called Thor's Helmet. Cataloged as NGC 2359, the striking nebula is located about 15,000 light-years away in the constellation Canis Major. The helmet is actually more like a cosmic bubble, blown as the wind from the bright, massive star near the bubble's center sweeps through the surrounding molecular cloud. Known as a Wolf-Rayet star, the energetic star is a blue giant thought to be in a brief, pre-supernova stage of evolution. The remarkable color composite combines broad and narrow band images - including a deep exposure recorded with an H-alpha filter. The H-alpha image traces the light from the region's glowing atomic hydrogen gas. Heroically sized even for a Norse god, this Thor's Helmet is about 30 light-years across.
Credit & Copyright: Don Goldman -
Astronomy Picture of the Day
2006 February 3
Cosmic Tornado HH49/50
Explanation: Light-years in length, this cosmic tornado is actually a powerful jet cataloged as HH (Herbig-Haro) 49/50 blasting down from the top of a Spitzer Space Telescope view. Though such energetic outflows are well known to be associated with the formation of young stars, the exact cause of the spiraling structures apparent in this case is still mysterious. The embryonic star responsible for the 100-kilometer per second jet is located just off the top of the picture, while the bright star seen near the tip of the jet may just by chance lie along the line of sight. In the false-color infrared image, the tornado glows with infrared light generated as the outflow heats surrounding dust clouds. The color coding shows a trend from red to blue hues at the tornado's tip indicating a systematic increase in emission at shorter wavelengths. The trend is thought to indicate an increase in molecular excitation closer to where the head of the jet is impacting interstellar gas. HH49/50 is about 450 light-years distant, located in the Chamaeleon I molecular cloud.
Credit: J. Bally (Univ. of Colo.) et al., JPL-Caltech, NASA -
Astronomy Picture of the Day
2006 February 4
Shadow Set
Explanation: A nearly full Moon and planet Earth's shadow set together in this scene captured on January 13th from snowy Mt. Jelm, home of the Wyoming Infrared Observatory. For early morning risers (and late to bed astronomers), shadow set in the western sky is a daily apparition whose subtle beauty is often overlooked in favor of the more colorful eastern horizon. Extending through the dense atmosphere, Earth's setting shadow is seen in this picture as a dark blue band along the distant horizon, bounded above by a pinkish glow or antitwilight arch. Known as the Belt of Venus, the arch's lovely color is due to backscattering of reddened light from the rising Sun. The setting Moon's light is also reddened by the long sight-line through the atmosphere.
Credit: J. Bonnell, D. Macomb, R. Canterna, WIRO -
Astronomy Picture of the Day
2006 February 5
A Sun Pillar in Red and Violet
Explanation: Sometimes the unknown is beautiful. In 2000 February near Lake Tahoe, Nevada, two amateur photographers noticed an unusual red column of light rise mysteriously from a setting sun. During the next few minutes, they were able to capture the pillar and a photogenic sunset on film. Pictured above, the red column is seen above a serene Lake Tahoe and snow-capped mountains across from Lake Tahoe-Nevada State Park. The mysterious column, they learned later, is a Sun Pillar, a phenomenon where sunlight reflects off of distant falling ice crystals.
Credit & Copyright: Jim Kirkpatrick & Brigitte Heiter-Kirkpatrick -
Astronomy Picture of the Day
2006 February 6
The N44 Superbubble
Explanation: What created this gigantic hole? The vast emission nebula N44 in our neighboring galaxy the Large Magellanic Cloud has a large, 250 light-year hole and astronomers are trying to figure out why. One possibility is particle winds expelled by massive stars in the bubble's interior that are pushing out the glowing gas. This answer has been recently found to be inconsistent with measured wind velocities, however. Another possibility is that the expanding shells of old supernovas have sculpted the unusual space cavern. An unexpected clue of hot X-ray emitting gas was recently been detected escaping the N44 superbubble. The above image, here digitally sharpened, was taken in three very specific colors by the huge 8-meter Gemini South Telescope on Cerro Pachon in Chile.
Credit & Copyright: Gemini Obs., AURA, NSF -
Astronomy Picture of the Day
2006 February 7
UB 313: Larger than Pluto
Explanation: What do you call an outer Solar System object that is larger than Pluto? Nobody is yet sure. The question arose recently when 2003 UB313, an object currently twice as far out as Pluto and not in the plane with the rest of the planets, was verified recently to be 30 percent wider than Pluto. UB313's size was measured by a noting its distance from the Sun and how much infrared light it emits. Previous size estimates were based only on visible light and greatly affected by how reflective the object is. Whether 2003 UB313 is officially declared a planet will be answered shortly by the International Astronomical Union. In the above picture, a scientific artist has imagined UB313 in its distant orbit around the Sun coupled with a hypothetical moon.
Illustration Credit & Copyright: Thierry Lombry -
Astronomy Picture of the Day
2006 February 8
The Great Basin on Tethys
Explanation: Some moons wouldn't survive the collision. Tethys, one of Saturn's larger moons at about 1,000 kilometers in diameter, survived the collision, but sports today the expansive impact crater Odysseus. Sometimes called the Great Basin, Odysseus occurs on the leading hemisphere of Tethys and shows its great age by the relative amount of smaller craters that occur inside its towering walls. The density of Tethys is similar to water-ice. The above digitally enhanced image was captured late last year by the robot Cassini spacecraft in orbit around Saturn as it swooped past the giant ice ball.
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA -
Astronomy Picture of the Day
2006 February 9
NGC 1309 and Friends
Explanation: A gorgeous spiral galaxy some 100 million light-years distant, NGC 1309 lies on the banks of the constellation Eridanus. NGC 1309 spans about 30,000 light-years, one third the size of our larger Milky Way galaxy. Bluish clusters of young stars and dust lanes are seen to trace out NGC 1309's spiral arms as they wind around an older yellowish star population at its core. Not just another pretty face-on spiral galaxy, observations of NGC 1309's recent supernova and cepheid stars contribute to the calibration of the expansion of the Universe. Still, after you get over this beautiful galaxy's grand design, check out the array of more distant background galaxies also recorded in the sharp Hubble Space Telescope view.
Credit: NASA, ESA, The Hubble Heritage Team, (STScI / AURA) and A. Riess (STScI) -
Astronomy Picture of the Day
2006 February 10
M8: The Lagoon Nebula
Explanation: This beautiful cosmic cloud is a popular stop on telescopic tours of the constellation Sagittarius. Eighteenth century cosmic tourist Charles Messier cataloged the bright nebula as M8, while modern day astronomers recognize the Lagoon Nebula as an active stellar nursery about 5,000 light-years distant, in the direction of the center of our Milky Way Galaxy. Striking details can be traced through this remarkable picture, processed to reveal the Lagoon's range of filaments of glowing hydrogen gas and dark dust clouds along with the brighter, turbulent hourglass region at the upper right. The view is a color composite of narrow and broad band images recorded under dark skies in northwestern Arizona. At the Lagoon's estimated distance, the picture spans about 30 light-years.
Image Credit & Copyright: Processing: Tom Davis, Acquisition: Jim Misti -
Astronomy Picture of the Day
2006 February 11
Plato and the Lunar Alps
Explanation: The dark-floored, 95 kilometer wide crater Plato (top) and sunlit peaks of the lunar Alps are highlighted in this sharp digital mosaic of the Moon's surface. While the Alps of planet Earth were uplifted over millions of years as continental plates slowly collided, the lunar Alps were likely formed by a sudden collision that created the giant impact basin known as the Mare Imbrium (Sea of Rains). The mare's generally smooth, lava-flooded floor is seen extending to the left. The prominent straight feature cutting through the mountain range (lower right) is the lunar Alpine Valley, about 160 kilometers long and up to 10 kilometers wide. Of course, the large, bright alpine mountain near bottom center is named Mont Blanc and reaches over 3 kilometers above the lunar surface. Lacking an atmosphere, not to mention snow, the lunar Alps are probably not an ideal site for the Winter Olympic Games. Still, a 150 pound skier would weigh a mere 25 pounds on the Moon.
Credit & Copyright: Alan Friedman -
Astronomy Picture of the Day
2006 February 12
Phoebe: Comet Moon of Saturn
Explanation: Was Saturn's moon Phoebe once a comet? Images from the robotic Cassini spacecraft taken two years ago when entering the neighborhood of Saturn indicate that Phoebe may have originated in the outer Solar System. Phoebe's irregular surface, retrograde orbit, unusually dark surface, assortment of large and small craters, and low average density appear consistent with the hypothesis that Phoebe was once part of the Kuiper belt of icy comets beyond Neptune before being captured by Saturn. Visible in the above image of Phoebe are craters, streaks, and layered deposits of light and dark material. The image was taken from around 30,000 kilometers out from this 200-kilometer diameter moon. Two weeks after taking the above image, Cassini fired its engines to decelerate into orbit around Saturn.
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA -
Astronomy Picture of the Day
2006 February 13
The N44 Emission Nebula
Explanation: N44 is one of the largest and most intricate nebulas in this part of the universe. Located in our galactic neighbor the Large Magellanic Cloud, N44 houses numerous massive bright stars, lengthy lanes of dark dust, and vast clouds of hydrogen gas that glows red. The red color of the N44 emission nebula comes from pervasive hydrogen atoms re-acquiring electrons that were knocked away by energetic light from massive stars. The central stars also appear to have somehow created the huge superbubble visible in the lower left. N44, pictured above, spans about 1,000 light years and lies about 170,000 light years distant.
Credit & Copyright: WFI, MPG/ESO 2.2-m Telescope, La Silla, ESO -
Astronomy Picture of the Day
2006 February 14
Dust and Light in the Rosette Nebula
Explanation: What creates the cosmic dust sculptures in the Rosette Nebula? Noted for the common beauty of its overall shape, parts of the Rosette Nebula, also known as NGC 2244, show beauty even when viewed up close. Visible above are globules of dark dust and gas that are slowly being eroded away by the energetic light and winds by nearby massive stars. Left alone long enough, the molecular-cloud globules would likely form stars and planets. The Rosette Nebula spans about 50 light-years across, lies about 4,500 light-years away, and can be seen with a small telescope towards the constellation of Monoceros.
Credit & Copyright: Nicolas Outters (Observatoire d'Orange)
