Astronomy fanatica

last SG · 2005-02-27T00:18:37+00:00

u'll find it on page 4 of this thread

poon cho tang SG

Astronomy Picture of the Day

2006 January 20

LL Ori and the Orion Nebula

Explanation: This esthetic close-up of cosmic clouds and stellar winds features LL Orionis, interacting with the Orion Nebula flow. Adrift in Orion's stellar nursery and still in its formative years, variable star LL Orionis produces a wind more energetic than the wind from our own middle-aged Sun. As the fast stellar wind runs into slow moving gas a shock front is formed, analogous to the bow wave of a boat moving through water or a plane traveling at supersonic speed. The small, arcing, graceful structure just above and left of center is LL Ori's cosmic bow shock, measuring about half a light-year across. The slower gas is flowing away from the Orion Nebula's hot central star cluster, the Trapezium, located off the upper left corner of the picture. In three dimensions, LL Ori's wrap-around shock front is shaped like a bowl that appears brightest when viewed along the "bottom" edge. The beautiful picture is part of a large mosaic view of the complex stellar nursery in Orion, filled with a myriad of fluid shapes associated with star formation.

Credit: NASA, ESA, and The Hubble Heritage Team

poon cho tang SG

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

poon cho tang SG

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

poon cho tang SG

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

poon cho tang SG

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

poon cho tang SG

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

poon cho tang SG

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

poon cho tang SG

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

poon cho tang SG

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)

poon cho tang SG

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

poon cho tang SG

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

poon cho tang SG

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

poon cho tang SG

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

poon cho tang SG

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

poon cho tang SG

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

poon cho tang SG

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

poon cho tang SG

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

poon cho tang SG

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

poon cho tang SG

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

poon cho tang SG

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

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