Astronomy picture of the day

RaTtY81 SG

2006 February 17

Explanation: A massive star ends life as a supernova, blasting its outer layers back to interstellar space. The spectacular death explosion is initiated by the collapse of what has become an impossibly dense stellar core. Pictured is the expanding supernova remnant Puppis A - one of the brightest sources in the x-ray sky. Now seen to be about 10 light-years in diameter, light from the initial stellar explosion first reached Earth a few thousand years ago. Recorded by the Chandra Observatory's x-ray cameras, the inset view shows striking details of the strong shock wave disrupting an interstellar cloud as the shock sweeps through preexisting material. The larger field ROSAT image also captures a pinpoint source of x-rays near the remnant's center. The source is a young neutron star, the remnant of the collapsed stellar core kicked out by the explosion and moving away at about 1,000 kilometers per second.

Credit: Chandra: NASA / CXC / GSFC, U.Hwang et al.; ROSAT: NASA/GSFC/S.Snowden et al.

LinYu SG

wow nice pic and fine details
Laughing

RaTtY81 SG

yea Mr. Green check out Iapetus on one of the thread i posted.

RaTtY81 SG

2006 February 18

Explanation: This dream-like image of Mir was recorded by astronauts as the space shuttle orbiter Atlantis approached the Russian space station prior to docking during the STS-76 mission in 1996. Sporting spindly appendages and solar panels, Mir resembles a whimsical flying insect hovering about 350 kilometers above New Zealand's South Island and the city of Nelson near Cook Strait. Mir was launched 20 years ago this week, and served as a continuously occupied orbital outpost until August 1999. Mir was visited by over 100 spacefarers from the nations of planet Earth including, Russia, the United States, Great Britain, Germany, France, Japan, Austria, Kazakhstan and Slovakia. The Mir was deorbited in March 2001.

Credit: STS-76 Crew, NASA

RaTtY81 SG

2006 February 19

Explanation: The Whirlpool Galaxy is a classic spiral galaxy. At only 30 million light years distant and fully 60 thousand light years across, M51, also known as NGC 5194, is one of the brightest and most picturesque galaxies on the sky. The above image is a digital combination of a ground-based image from the 0.9-meter telescope at Kitt Peak National Observatory and a space-based image from the Hubble Space Telescope highlighting sharp features normally too red to be seen. Anyone with a good pair of binoculars, however, can see this Whirlpool toward the constellation of Canes Venatici. M51 is a spiral galaxy of type Sc and is the dominant member of a whole group of galaxies. Astronomers speculate that M51's spiral structure is primarily due to its gravitational interaction with a smaller galaxy just off the top of this digitally sharpened image.

Credit: N. Scoville (Caltech), T. Rector (U. Alaska, NOAO) et al., Hubble Heritage Team, NASA

RaTtY81 SG

2006 February 20

Explanation: Who dunnit? Like a scene from a space mystery movie, a spacesuit floated away from the International Space Station earlier this month, but no investigation was needed. It was pushed out by the space station crew. Dubbed Suitsat-1, the unneeded Russian Orlan spacesuit filled mostly with old clothes was fitted with a faint radio transmitter and released to orbit the Earth. Suitsat-1 will orbit once every 90 minutes until it burns up in the Earth's atmosphere within a few weeks. The suit circled the Earth twice before its radio signal became unexpectedly weak. Pictured above, the lifeless spacesuit was photographed as it drifted away from the Earth-orbiting space station earlier this month.

Credit: ISS Expedition 12 Crew, NASA

RaTtY81 SG

2006 February 21

Explanation: The famous Horsehead Nebula in Orion is not alone. A deep exposure shows that the dark familiar shaped indentation, visible just below center, is part of a vast complex of absorbing dust and glowing gas. To bring out details of the Horsehead's pasture, amateur astronomers at the Star Shadow Remote Observatory in New Mexico, USA fixed a small telescope on the region for over seven hours filtering out all but a very specific color of red light emitted by hydrogen. They then added the image to a full color frame taken over three hours. The resulting spectacular picture details an intricate tapestry of gaseous wisps and dust-laden filaments that were created and sculpted over eons by stellar winds and ancient supernovas. The Horsehead Nebula lies 1,500 light years distant towards the constellation of Orion. Two stars from the Orion's Belt can be found in the above image.

Credit & Copyright: Star Shadows Remote Observatory

RaTtY81 SG

2006 February 22

Explanation: Why is Saturn's small moon Telesto so smooth? Possibly Telesto is covered with a type of granular icy material similar to that suspected of covering Pandora, another of Saturn's small moons. If so, Telesto might be more like a pile of rubble than a solid body. This recently uncovered Solar System mystery is currently a topic of research, however. The unexpected finding originated last October when the robot Cassini spacecraft, currently orbiting Saturn, swooped past the 24-kilometer moon and captured the first ever image of Telesto's surface. Telesto orbits Saturn always just ahead of the much larger moon Tethys. Pictured above, Telesto's unusually smooth surface was found to show some large craters and boulders, but not the high density of craters found on nearby Tethys or most other Saturnian moons.

Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

ndmmxiaomayi SG

Based on data from Cassini spacecraft instruments, researchers are now arguing that liquid water reservoirs exist only tens of meters below the surface of Saturn's small (500 kilometer diameter) but active moon Enceladus. The exciting new results center around towering jets and plumes of material erupting from the moon's surface. The plumes originate in the long tiger stripe fractures of the south polar region pictured here. Detailed models suport conclusions that the plumes arise from near-surface pockets of liquid water at temperatures of 273 kelvins (0 degrees Celsius), even though Enceladus has a surface temperature of about 73 kelvins (-200 degrees Celsius). Clearly an important step in the search for water and the potential for the origin of life beyond planet Earth, such near-surface reservoirs of water would be far more accessible than, for example, the internal ocean detected on the Jovian moon Europa.

Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

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