CDer:000024255 楼主: jadiyd

[视图资料] Astronomy Picture of the Day 2010-每日天文一图第四季

 楼主| 发表于 2010-02-09 15:20 | 显示全部楼层
本帖最后由 jadiyd 于 2010-2-9 16:22 编辑

2010 February 9

Night Launch of the Space Shuttle Endeavour
Credit: NASA
Explanation: Sometimes, the space shuttle launches at night. Pictured above, the space shuttle Endeavour lifted off in yesterday's early morning hours from Launch Pad 39A in Kennedy Space Center, Florida, USA, bound for the International Space Station (ISS). A night launch, useful for reaching the space station easily during some times of the year, frequently creates vivid launch imagery. The shuttle, as pictured above, is framed by an enormous but typical exhaust plume ejected as the shuttle's powerful rockets began lifting the two million kilogram space bus into Earth orbit. Endeavour's mission, labeled STS-130, includes the delivery of the Tranquility module to the space station. Tranquility will provide extra room for space station astronauts and includes a large circular set of windows designed to bestow vastly improved views of the Earth, the night sky, and the space station itself.


 楼主| 发表于 2010-02-10 15:57 | 显示全部楼层
2010 February 9

Sakurajima Volcano with Lightning
Credit & Copyright: Martin Rietze (Alien Landscapes on Planet Earth)
Explanation: Why does a volcanic eruption sometimes create lightning? Pictured above, the Sakurajima volcano in southern Japan was caught erupting early last month. Magma bubbles so hot they glow shoot away as liquid rock bursts through the Earth's surface from below. The above image is particularly notable, however, for the lightning bolts caught near the volcano's summit. Why lightning occurs even in common thunderstorms remains a topic of research, and the cause of volcanic lightning is even less clear. Surely, lightning bolts help quench areas of opposite but separated electric charges. One hypothesis holds that catapulting magma bubbles or volcanic ash are themselves electrically charged, and by their motion create these separated areas. Other volcanic lightning episodes may be facilitated by charge-inducing collisions in volcanic dust. Lightning is usually occurring somewhere on Earth, typically over 40 times each second.
 楼主| 发表于 2010-02-11 13:36 | 显示全部楼层
2010 February 11

Star Cluster M34
Credit & Copyright: Bob Franke
Explanation: This pretty open cluster of stars, M34, is about the size of the Full Moon on the sky. Easy to appreciate in small telescopes, it lies some 1,800 light-years away in the constellation Perseus. At that distance, M34 physically spans about 15 light-years. Formed at the same time from the same cloud of dust and gas, all the stars of M34 are about 200 million years young. But like any open star cluster orbiting in the plane of our galaxy, M34 will eventually disperse as it experiences gravitational tides and encounters with the Milky Way's interstellar clouds and other stars. Over four billion years ago, our own Sun was likely formed in a similar open star cluster.
 楼主| 发表于 2010-02-12 15:22 | 显示全部楼层
2010 February 12

Teide Sky Trails
Credit & Copyright: Daniel López
Explanation: The snow capped Teide volcano is reflected in a pool of water in this nearly symmetric night sky view from the Canary Island Tenerife. Bright north star Polaris stands above the peak in an exposure that also captures the brilliant trail of a polar orbiting Iridium satellite. Of course, with the camera fixed to a tripod, the stars themselves produce concentric trails in long exposures, a reflection of the Earth's rotation around its axis. In fact, you can add about 4.5 hours of exposure time to this image by just sliding your cursor over the picture. Large astronomical observatories also take advantage of the calm Canary Island sky.
 楼主| 发表于 2010-02-13 13:56 | 显示全部楼层
2010 February 13

Waterway to Orbit
Credit & Copyright: James Vernacotola
Explanation: The 32nd shuttle mission to the International Space Station, STS-130, left planet Earth on February 8. Its early morning launch to orbit from Kennedy Space Center's pad 39A followed the long, graceful, eastward arc seen in this 2 minute time exposure. Well composed, the dramatic picture also shows the arc's watery reflection from the Intracoastal Waterway Bridge, in Ponte Vedra, Florida, about 115 miles north of the launch site. In the celestial background a waning crescent Moon and stars left their own short trails against the still dark sky. The brightest star trail near the moon was made by red supergiant Antares, alpha star of the constellation Scorpius.
 楼主| 发表于 2010-02-14 15:45 | 显示全部楼层
2010 February 14

Field of Rosette
Credit & Copyright: Rogelio Bernal Andreo (Deep Sky Colors)
Explanation: What surrounds the florid Rosette nebula? To better picture this area of the sky, the famous flowery emission nebula on the far right has been captured recently in a deep and dramatic wide field image that features several other sky highlights. Designated NGC 2237, the center of the Rosette nebula is populated by the bright blue stars of open cluster NGC 2244, whose winds and energetic light are evacuating the nebula's center. Below the famous flower, a symbol of Valentine's Day, is a column of dust and gas that appears like a rose's stem but extends hundreds of light years. Across the above image, the bright blue star just left and below the center is called S Monocerotis. The star is part of the open cluster of stars labelled NGC 2264 and known as the Snowflake cluster. To the right of S Mon is a dark pointy featured called the Cone nebula, a nebula likely shaped by winds flowing out a massive star obscured by dust. To the left of S Mon is the Fox Fur nebula, a tumultuous region created by the rapidly evolving Snowflake cluster. The Rosette region, at about 5,000 light years distant, is about twice as far away as the region surrounding S Mon. The entire field can be seen with a small telescope toward the constellation of the Unicorn (Monoceros).
 楼主| 发表于 2010-02-15 19:52 | 显示全部楼层
2010 February 15

Cassini Spacecraft Crosses Saturn's Ring Plane
Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA
Explanation: If this is Saturn, where are the rings? When Saturn's "appendages" disappeared in 1612, Galileo did not understand why. Later that century, it became understood that Saturn's unusual protrusions were rings and that when the Earth crosses the ring plane, the edge-on rings will appear to disappear. This is because Saturn's rings are confined to a plane many times thinner, in proportion, than a razor blade. In modern times, the robot Cassini spacecraft orbiting Saturn now also crosses Saturn's ring plane. A series of plane crossing images from late February was dug out of the vast online Cassini raw image archive by interested Spanish amateur Fernando Garcia Navarro. Pictured above, digitally cropped and set in representative colors, is the striking result. Saturn's upper atmosphere appear in gold. Since Saturn just passed its equinox, today the ring plane is pointed close to the Sun and the rings could not cast the high dark shadows seen across the top of this image, taken back in 2005. Moons appear as bumps in the rings.
 楼主| 发表于 2010-02-16 23:25 | 显示全部楼层
2010 February 16

Dark Shuttle Approaching
Credit: Expedition 22 Crew, NASA
Explanation: What's that approaching? Astronauts on board the International Space Station first saw it far in the distance. Soon it enlarged to become a dark silhouette. As it came even closer, the silhouette appeared to be a spaceship. Finally, at just past 11 pm (CST) last Tuesday, the object, revealed to be the Space Shuttle Endeavor, docked as expected with the Earth-orbiting space station. Pictured above, Endeavor was imaged near Earth's horizon as it approached, where several layers of the Earth's atmosphere were visible. Directly behind the shuttle is the mesosphere, which appears blue. The atmospheric layer that appears white is the stratosphere, while the orange layer is Earth's Troposphere. This shuttle mission, which began with a dramatic night launch and will continue into next week, has many tasks planned. These tasks include the delivery of the Tranquility Module which includes a cupola bay window complex that may allow even better views of spaceships approaching and leaving the space station.
 楼主| 发表于 2010-02-17 17:35 | 显示全部楼层
2010 February 17

An Unusually Smooth Surface on Saturn's Calypso
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
Explanation: Why is this moon of Saturn so smooth? This past weekend, humanity's Saturn-orbiting Cassini spacecraft passed as close to Saturn's small moon Calypso as it ever has, and imaged the small moon in unprecedented detail. Pictured above is an early return, raw, unprocessed image of the 20-km long irregularly shaped moon. Like its sister moon Telesto and the shepherd moon Pandora, Calypso has shown itself to be usually smooth, much smoother than most of Saturn's larger moons. A leading hypothesis for Calypso's smoothness is that much of the moon's surface is actually a relatively loose jumble of rubble -- making Calypso a rubble-pile moon. The loose nature of the small ice pieces allows them to fill in many small craters and other surface features. Calypso orbits Saturn always behind Saturn's much larger moon Tethys, whereas Telesto's orbit always precedes Tethys. Calypso's extremely white surface -- not unlike fresh snow -- may result from the continuous accumulation of fresh ice particles falling in from Saturn's E ring.
 楼主| 发表于 2010-02-18 17:01 | 显示全部楼层
2010 February 18

Vesta Near Opposition
Credit & Copyright: Jimmy Westlake
Explanation: Main belt asteroid 4 Vesta is at its brightest now. The small world is near opposition (opposite the Sun in the sky) and closest to Earth. But even at its brightest, Vesta is just too faint to spot with the naked-eye. Still, over the next few days it will be relatively easy to find in the constellation Leo, sharing a typical binocular field of view with bright star Gamma Leonis (aka Algieba). In fact on February 16 Vesta passed between Gamma Leonis and close neighbor on the sky 40 Leonis. Gamma Leonis is the brightest star in these two panels, while the second brightest star, 40 Leonis, is directy to its right. As marked, Vesta is the third brightest "star" in the field. Vesta shifts position between the two panels from well below 40 Leonis on Feb. 14 to near the top of the frame from Feb. 16, shooting the gap between the close Gamma/40 Leonis pair. Of course, premier close-up views of the asteroid will be possible after the ion-powered Dawn spacecraft arrives at Vesta in August of 2011.
 楼主| 发表于 2010-02-19 14:41 | 显示全部楼层
2010 February 19

WISE Infrared Andromeda
Credit: NASA / JPL-Caltech / UCLA
Explanation: This sharp, wide-field view features infrared light from the spiral Andromeda Galaxy (M31). Dust heated by Andromeda's young stars is shown in yellow and red, while its older population of stars appears as a bluish haze. The false-color skyscape is a mosaic of images from NASA's new Wide-field Infrared Survey Explorer (WISE) satellite. With over twice the diameter of our Milky Way, Andromeda is the largest galaxy in the local group. Andromeda's own satellite galaxies M110 (below) and M32 (above) are also included in the combined fields. Launched in December 2009, WISE began a six month long infrared survey of the entire sky on January 14. Expected to discover near-Earth asteroids as well as explore the distant universe, its sensitive infrared detectors are cooled by frozen hydrogen.
 楼主| 发表于 2010-02-20 13:13 | 显示全部楼层
2010 February 20

Geostationary Highway
Credit & Copyright: Babak Tafreshi (TWAN) Explanation: Put a satellite in a circular orbit about 42,000 kilometers from the center of the Earth (36,000 kilometers or so above the surface) and it will orbit once in 24 hours. Because that matches Earth's rotation period, it is known as a geosynchronous orbit. If that orbit is also in the plane of the equator, the satellite will hang in the sky over a fixed location in a geostationary orbit. As predicted in the 1940s by futurist Arthur C. Clark, geostationary orbits are in common use for communication and weather satellites, a scenario now well-known to astroimagers. Deep images of the night sky made with telescopes that follow the stars can also pick up geostationary satellites glinting in sunlight still shining far above the Earth's surface. Because they all move with the Earth's rotation against the background of stars, the satellites leave trails that seem to follow a highway across the celestial landscape. For example, in this wide view of the nearly equatorial Orion region, individual frames were added to create a 10 minute long exposure. It shows Orion's belt stars and well-known nebulae along with many 2.5 degree long geostationary satellite trails. The frames are from an ingenious movie, featuring the geostationary satellite highway.
 楼主| 发表于 2010-02-21 13:25 | 显示全部楼层
本帖最后由 jadiyd 于 2010-2-24 19:14 编辑

2010 February 21

NGC 2440: Cocoon of a New White Dwarf
Credit: H. Bond (STScI), R. Ciardullo (PSU), WFPC2, HST, NASA
Explanation: Like a butterfly, a white dwarf star begins its life by casting off a cocoon that enclosed its former self. In this analogy, however, the Sun would be a caterpillar and the ejected shell of gas would become the prettiest of all! In the above cocoon, the planetary nebula designated NGC 2440, contains one of the hottest white dwarf stars known. The white dwarf can be seen as the bright dot near the photo's center. Our Sun will eventually become a white dwarf butterfly but not for another 5 billion years. The above false color image was post-processed by Forrest Hamilton.

说明:就像一只蝴蝶一样,白矮星抛弃了星茧、结束了原先的生命从而开始了新的旅程。在这个比喻里,然而,太阳将是一只小毛虫,喷射出了气体外壳,形成了一直最美丽的蝴蝶。上面这个星茧是一个行星状星云,它被命名为NGC2440,其中含有迄今为止所知最炽热的白矮星之一。在上面影像的中央附近有一个明亮的点,那就是白矮星。我们太阳再过50亿年,也将最终变成一颗白矮星。上面的这张假色影像Forrest Hamilton后期处理。

 楼主| 发表于 2010-02-22 15:14 | 显示全部楼层
本帖最后由 jadiyd 于 2010-2-24 19:15 编辑

2010 February 22

Galaxy Group Hickson 31
Credit: NASA, ESA, J. English (U. Manitoba), and the Hubble Heritage Team (STScI/AURA);
Acknowledgement: S. Gallagher (U. Western Ontario)
Explanation: Will the result of these galactic collisions be one big elliptical galaxy? Quite possibly, but not for another billion years. Pictured above, several of the dwarf galaxies of in the Hickson Compact Group 31 are seen slowly merging. Two of the brighter galaxies are colliding on the far left, while an elongated galaxy above is connected to them by an unusual bridge of stars. Inspection of the above image further indicates that the bright duo trail a rope of stars pointing to the spiral galaxy on the far right. Most assuredly, the pictured galaxies of Hickson Compact Group 31 will pass through and destroy each other, millions of stars will form and explode, and thousands of nebula will form and dissipate before the dust settles and the final galaxy emerges about one billion years from now. The above image is a composite of images taken in infrared light by the Spitzer Space Telescope, ultraviolet light by the GALEX space telescope, and visible light by the Hubble Space Telescope. Hickson Compact Group 31 spans about 150 thousand light years and lies about 150 million light years away toward the constellation of Eridanus.


 楼主| 发表于 2010-02-23 23:19 | 显示全部楼层
本帖最后由 jadiyd 于 2010-2-24 19:15 编辑

2010 February 23

Exceptional Rocket Waves Destroy Sun Dog
Credit & Copyright: George C. Privon (U. Virginia)
Explanation: What created those rocket waves, and why did they destroy that sun dog? Close inspection of the above image shows not only a rocket rising near the center, but unusual air ripples around it and a colorful sundog to the far right. The rocket, carrying the Solar Dynamics Observatory (SDO), lifted off two weeks ago from Cape Canaveral, Florida, USA into a cold blue sky. The SDO is designed to observe the Sun continuously over the next several years, exploring the Sun's atmosphere at high resolution and fast time scales. The air ripples -- seen about one minute after launch -- were unexpected, as was the sudden disappearance of the sundog after the ripples passed. Noticed and recorded by several onlookers, there has been much speculation about the origin of the ripples. An ongoing discussion about them can be joined here in APOD's discussion board the Asterisk. A leading hypothesis holds that the ripples resulted from a sonic boom created as the rocket broke the sound barrier, which then jumbled a thin layer of ice crystals that were aligned to create the sundog. Lingering questions include why other rocket launches don't produce air ripples as noticeable, and why the ripples appeared more prominent above the rocket. If you know of images of any other aircraft or spacecraft that have produced similar air ripples, please post them to the discussion thread -- they may be help create a better understanding of the effect.


 楼主| 发表于 2010-02-24 19:16 | 显示全部楼层
2010 February 24

Astronaut Installs Panoramic Space Window
Credit: ISS Expedition 22 Crew, Shuttle Endeavour STS-130 Crew, NASA
Explanation: This space job was almost complete. Floating just below the International Space Station, astronaut Nicholas Patrick put some finishing touches on the newly installed cupola space windows last week. Patrick was a mission specialist onboard the recently completed space shuttle Endeavor's STS-130 mission to the ISS. Pictured, Patrick floats near the outermost of seven windows on the new cupola of the just-installed Tranquility module. Patrick hovers about 340 kilometers over the Earth's surface, well in front of the blue sky, blue water, and white clouds pictured far in the background. In the above image, covers on windows three and four were in place and clearly labelled. Images from inside the ISS's new panoramic cupola are now available.

说明:此次太空任务几近完成。上周,漂浮在国际空间站下方的宇航员Nicholas Patrick正在对新安装的圆顶太空窗进行一些收尾工作Patrick是一名任务专家,完成了此次奋进号航天飞机飞往国际空间站代号为STS-130的任务。上面的影像中,Patrick漂浮在拥有7个窗口圆顶的最外侧,这也是新安装在宁静舱上的一个圆顶Patrick漂浮在地球上空大约340万公里的高空,正好位于蓝色天空的前方,蓝色海水,白色的云朵出现在遥远的背景中。在上面这张影像中,可以看到清晰标注的3号,4号窗口。如今已经从国际空间站新安装的全景圆顶内拍摄到影像

 楼主| 发表于 2010-02-25 16:35 | 显示全部楼层
2010 February 25

Edge-on Spiral Galaxy NGC 891
Credit & Copyright: Bob Franke
Explanation: This beautiful cosmic portrait features NGC 891. The spiral galaxy spans about 100 thousand light-years and is seen almost exactly edge-on from our perspective. In fact, about 30 million light-years distant in the constellation Andromeda, NGC 891 looks a lot like our Milky Way. At first glance, it has a flat, thin, galactic disk and a central bulge cut along the middle by regions of dark obscuring dust. Also apparent in NGC 891's ege-on presentation are filaments of dust that extend hundreds of light-years above and below the center line. The dust has likely been blown out of the disk by supernova explosions or intense star formation activity. Faint neighboring galaxies can also been seen near this galaxy's disk.


 楼主| 发表于 2010-02-26 15:30 | 显示全部楼层
2010 February 26

Chasing Carina
Credit & Copyright: Dieter Willasch
Explanation: A jewel of the southern sky, the Great Carina Nebula, aka NGC 3372, spans over 300 light-years. Near the upper right of this expansive skycape, it is much larger than the more northerly Orion Nebula. In fact, the Carina Nebula is one of our galaxy's largest star-forming regions and home to young, extremely massive stars, including the still enigmatic variable Eta Carinae, a star with well over 100 times the mass of the Sun. Nebulae near the center of the 10 degree wide field include NGC 3576 and NGC 3603. Near center at the top of the frame is open star cluster NGC 3532, the Wishing Well Cluster. More compact, NGC 3766, the Pearl Cluster, can be spotted at the left. Anchoring the lower left of the cosmic canvas is another large star-forming region, IC 2948 with embedded star cluster IC 2944. That region is popularly known as the Running Chicken Nebula.


 楼主| 发表于 2010-02-27 13:43 | 显示全部楼层
2010 February 27

Dawn's Endeavour
Credit & Copyright: Malcolm Park
Explanation: On February 21st, the Space Shuttle Endeavour and the International Space Station (ISS) flew through the sky near dawn over Whitby, Ontario, Canada. Along with star trails, both were captured in this single time exposure. Glinting in sunlight 350 kilometers above the Earth, Endeavour slightly preceeded the ISS arcing over the horizon. But the brighter trail and the brighter flare belongs to the space station just visted by Endeavour. Near the completion of the STS-130 mission, hours later Endeavour made a night landing at Kennedy Space Center.
 楼主| 发表于 2010-02-28 21:32 | 显示全部楼层
2010 February 28

Pauli Exclusion Principle: Why You Don't Implode
Credit & Copyright: Andrew Truscott & Randall Hulet (Rice U.)
Explanation: Why doesn't matter just bunch up? The same principle that keeps neutron stars and white dwarf stars from imploding also keeps people from imploding and makes normal matter mostly empty space. The observed reason is known as the Pauli Exclusion Principle. The principle states that identical fermions -- one type of fundamental matter -- cannot be in the same place at the same time and with the same orientation. The other type of matter, bosons, do not have this property, as demonstrated clearly by recently created Bose-Einstein condensates. Earlier this decade, the Pauli Exclusion Principle was demonstrated graphically in the above picture of clouds of two isotopes of lithium -- the left cloud composed of bosons while the right cloud is composed of fermions. As temperature drops, the bosons bunch together, while the fermions better keep their distance. The reason why the Pauli Exclusion Principle is true and the physical limits of the principle are still unknown.
 楼主| 发表于 2010-03-01 18:11 | 显示全部楼层
本帖最后由 jadiyd 于 2010-3-2 16:10 编辑

2010 March 1

Slope Streaks in Acheron Fossae on Mars
Credit: HiRISE, MRO, LPL (U. Arizona), NASA
Explanation: What creates these picturesque dark streaks on Mars? No one knows for sure. A leading hypothesis is that streaks like these are caused by fine grained sand sliding down the banks of troughs and craters. Pictured above, dark sand appears to have flowed hundreds of meters down the slopes of Acheron Fossae. The sand appears to flow like a liquid around boulders, and, for some reason, lightens significantly over time. This sand flow process is one of several which can rapidly change the surface of Mars, with other processes including dust devils, dust storms, and the freezing and melting of areas of ice. The above image was taken by the HiRise camera on board the Mars Reconnaissance Orbiter which has been orbiting Mars since 2006. Acheron Fossae is a 700 kilometer long trough in the Diacria quadrangle of Mars.

说明:是什么造成了火星上这些独特的条纹?没有人确切的知道。目前一种主要的假说就是,这些条纹是由细微的沙粒从山谷或者环形山滑落而成。上面的影像里,黑暗的沙子看上去就像从Acheron Fossae的斜坡上向下蔓延了数百米远。沙子看上去像液体一样在大石旁流淌一样,基于某些原因随着时间的流逝,特征也在显著的变淡。这种沙瀑是能迅速改变火星表面的方式之一,其它的过程包括沙尘暴沙暴,以及冰区的冻结以及融化过程。上面的影像是由安装在火星资源卫星上HiRise相机拍摄,从2006年开始它就已经绕火星飞行了。Acheron Fossae位于火星Diacria quadrangle区域内,是一条长达700公里长的沟槽

 楼主| 发表于 2010-03-02 16:08 | 显示全部楼层
2010 March 2

M78 and Reflecting Dust Clouds in Orion
Credit & Copyright: Ignacio de la Cueva Torregrosa
Explanation: An eerie blue glow and ominous columns of dark dust highlight M78 and other bright reflection nebula in the constellation of Orion. The dark filamentary dust not only absorbs light, but also reflects the light of several bright blue stars that formed recently in the nebula. Of the two reflection nebulas pictured above, the more famous nebula is M78, in the image center, while NGC 2071 can be seen to its lower left. The same type of scattering that colors the daytime sky further enhances the blue color. M78 is about five light-years across and visible through a small telescope. M78 appears above only as it was 1600 years ago, however, because that is how long it takes light to go from there to here. M78 belongs to the larger Orion Molecular Cloud Complex that contains the Great Nebula in Orion and the Horsehead Nebula.


 楼主| 发表于 2010-03-04 18:22 | 显示全部楼层
2010 March 3

The International Space Station from Above
Credit: STS-130 Crew, NASA
Explanation: The International Space Station (ISS) is the largest human-made object ever to orbit the Earth. The ISS is so large that it can be seen drifting overhead with the unaided eye, and is frequently imaged from the ground in picturesque fashion. Last month, the station was visited again by space shuttle, which resupplied the station and added a new module. The ISS is currently operated by the Expedition 22 crew, now consisting five astronauts including two supplied by USA's NASA, two by Russia's RKA, and one by Japan's JAXA. After departing the ISS, the crew of the space shuttle Endeavour captured the above spectacular vista of the orbiting space city high above the clouds, waters, and lands of Earth. Visible components include modules, trusses, and expansive solar arrays that gather sunlight that is turned into needed electricity.
 楼主| 发表于 2010-03-04 18:23 | 显示全部楼层
2010 March 4

NGC 4565: Galaxy on Edge
Image Credit & Copyright: Acquisition - Torsten Grossmann, Processing - Dietmar Hager
Explanation: Magnificent spiral galaxy NGC 4565 is viewed edge-on from planet Earth. Also known as the Needle Galaxy for its narrow profile, bright NGC 4565 is a stop on many telescopic tours of the northern sky, in the faint but well-groomed constellation Coma Berenices. This sharp, colorful image reveals the galaxy's bulging central core cut by obscuring dust lanes that lace NGC 4565's thin galactic plane. An assortment of other galaxies are included in the pretty field of view. Neighboring galaxy NGC 4562 is at the upper right. NGC 4565 itself lies about 40 million light-years distant, spanning some 100,000 light-years. Easily spotted with small telescopes, sky enthusiasts consider NGC 4565 to be a prominent celestial masterpiece Messier missed.


 楼主| 发表于 2010-03-05 19:36 | 显示全部楼层
2010 March 5

Deep Auriga
Image Credit & Copyright: Tunç Tezel (TWAN)
Explanation: The plane of our Milky Way Galaxy runs right through Auriga, the Charioteer. A good part of the ancient northern constellation's rich collection of nebulae and star clusters is featured in this expansive, 10 degree wide skyscape. Bright star Elnath lies near the bottom right, linking Auriga to another constellation, Taurus, the Bull. Three open star clusters, Charles Messier's M36, M37, and M38 line up in the dense star field above and left of Elnath, familiar to many binocular-equiped skygazers. But the deep exposure also brings out the reddish emission nebulae of star-forming regions IC 405, IC 410, and IC 417. E. E. Barnard's dark nebulae B34 and B226 just stand out against a brighter background. For help identifying even more of Auriga's deep sky highlights, put your cursor over the image.


 楼主| 发表于 2010-03-06 18:29 | 显示全部楼层
本帖最后由 jadiyd 于 2010-3-9 16:58 编辑

2010 March 6

Pillar at Sunset
Image Credit & Copyright: David Alquist
Explanation: Reddened light from the setting Sun illuminates the cloud banks hugging this snowy, rugged terrain. Inspiring a moment of quiet contemplation, the sunset scene included a remarkable pillar of light that seemed to connect the clouds in the sky with the mountains below. Known as a Sun pillar, the luminous column was produced by sunlight reflecting from flat, six-sided ice crystals formed high in the cold atmosphere and fluttering toward the ground. Last Monday, astronomers watched this Sun pillar slowly fade, as the twilight deepened and clearing, dark skies came to Mt. Jelm and the Wyoming Infrared Observatory.


 楼主| 发表于 2010-03-07 17:33 | 显示全部楼层
本帖最后由 jadiyd 于 2010-3-9 16:56 编辑

2010 March 7

Spirit Rover at Engineering Flats on Mars
Credit: Mars Exploration Rover Mission, JPL, NASA
Explanation: Is it art? If so, the paintbrush was the Spirit robotic rover, the canvas was the soil on Mars, and the artists were the scientists and engineers of the Mars Exploration Rover Mission. This panoramic picture, created in 2004 and shown above compressed horizontally, was mostly unintentional -- the MERS team was primarily instructing Spirit to investigate rocks in and around Hank's Hollow in a location called Engineering Flats on Mars. After creating the ground display with its treads, the Spirit rover was instructed to photograph the area along with itself in shadow. In 2010 as winter approaches in northern Mars, Spirit, still mired in sand, has been placed in an energy saving "hibernating" mode until spring arrives and more direct sunlight might be used to power the robotic explorer.

说明:这是艺术?如果是这样的话,画笔就是勇气号探测器,画布就是火星土壤,而艺术家就是火星探测器使命的科学家和工程师们。这张全景影像拍摄于2004年,显示了水平压缩了的影像,照片的产生几乎是无意识的,火星探测使命小组主要是指导勇气号探测汉克低洼地区的岩石,该地区被称为火星上的工程台地。在火星表面产生轮痕后,勇气号也为周围拍摄了照片,同时也拍到它自已的黑色剪影 2010年,当冬季来到火星北半球时,勇气号依旧陷在泥沙中,并处于节能状态“冬眠”中,直到春天来临,到时候将有更多的直射阳光被探测器用来产生电力。

 楼主| 发表于 2010-03-08 16:43 | 显示全部楼层
本帖最后由 jadiyd 于 2010-3-9 16:55 编辑

2010 March 8

Mars Over the Allalinhorn
Credit & Copright: Till Credner (AlltheSky.com)
Explanation: What's that bright object in the sky? A common question with answers that vary by time and season, the quick answer just after sunset in middle of last month, from the norther hemisphere, was Mars. The above picturesque panorama, taken during a ski trip from the Alps in Switzerland, shows not only Mars, but much more. Pine trees line the foreground, while numerous slopes leading up to the snow covered Allalinhorn mountain are visible in the distance. Stars dot the background, with the Beehive star cluster (M44) visible just below and to the left of Mars, while stars Castor and Pollux peak through the tree tops to the Mars' upper right. Mars will remain bright and in the constellation of the Crab (Cancer) until mid-May.
 楼主| 发表于 2010-03-09 16:54 | 显示全部楼层
2010 March 9

Galaxies Beyond the Heart: Maffei 1 and 2
Credit: NASA, JPL-Caltech, WISE Team
Explanation: The two galaxies on the far left were unknown until 1968. Although they would have appeared as two of the brighter galaxies on the night sky, the opaque dust of the central band of our Milky Way Galaxy had obscured them from being seen in visible light. The above image in infrared light taken by the recently launched Wide-Field Infrared Survey Explorer (WISE), however, finds these galaxies in great detail far behind -- but seemingly next to -- the photogenic Heart nebula (IC 1805). The spiral galaxy near the top is the easiest to spot and is known as Maffei 2. Just below and to its right is fuzzy-looking Maffei 1, the closest giant elliptical galaxy to Earth. The above false-colored image spans three full moons from top to bottom. The Maffei galaxies each span about 15,000 light years across and lie about 10 million light years away toward the constellation of the Queen of Ethiopia (Cassiopeia). On the image right, stars, gaseous filaments, and warm dust highlight a detailed infrared view of the Heart nebula.


 楼主| 发表于 2010-03-10 15:35 | 显示全部楼层
本帖最后由 jadiyd 于 2010-3-11 13:16 编辑

2010 March 10

Saturn's Moon Helene from Cassini
Explanation: What's happening on the surface of Saturn's moon Helene? The moon was imaged in unprecedented detail last week as the robotic Cassini spacecraft orbiting Saturn swooped to within two Earth diameters of the diminutive moon. Although conventional craters and hills appear, the above raw and unprocessed image also shows terrain that appears unusually smooth and streaked. Planetary astronomers will be inspecting these detailed images of Helene to glean clues about the origin and evolution of the 30-km across floating iceberg. Helene is also unusual because it circles Saturn just ahead of the large moon Dione, making it one of only four known moons to occupy a gravitational well known as a stable Lagrange point.


 楼主| 发表于 2010-03-11 13:16 | 显示全部楼层
本帖最后由 jadiyd 于 2010-3-12 20:03 编辑

2010 March 11

Yukon Aurora with Star Trails
Image Credit & Copyright: Yuichi Takasaka / TWAN / www.blue-moon.ca
Explanation: Fixed to a tripod, a camera can record graceful trails traced by stars as planet Earth rotates on its axis. But at high latitudes during March and April, it can also capture an aurora shimmering in the night. In fact, the weeks surrounding the equinox, in both spring and fall, offer a favorable season for aurora hunters. The possibilities are demonstrated in this beautiful moonlit vista from northwestern Canadian territory the Yukon. It was taken during the early morning of March 1, off the Klondike Highway about 60 kilometers south of Dawson City. To compose the picture, many short exposures were digitally combined to follow the concentric star trail arcs while including the greenish auroral curtains also known as the northern lights.


 楼主| 发表于 2010-03-12 20:02 | 显示全部楼层
2010 March 12

JWST: Mirrors and Masked Men
Image Courtesy: Ball Aerospace
Explanation: Who are these masked men? Technicians from Ball Aerospace and NASA at Marshall Space Flight Center's X-ray and Cryogenic Facility, of course, testing primary mirror segments of the James Webb Space Telescope (JWST). Scheduled for launch in 2014, JWST will be optimized for the infrared exploration of the early Universe, utilizing a primary mirror 21.3 feet across, composed of 18 hexagonal segments. Here, a group of JWST mirror segments are being prepared for tests to assure they meet the exacting mission requirements. The technicians' suits and masks help prevent contamination of the mirror surfaces. At the Marshall X-ray and Cryogenic Facility, the mirrors are tested in the large circular chamber after evacuating the air and cooling the chamber to -400 degrees Fahrenheit (only 60 degrees above absolute zero). The extremely low pressure and temperature simulate the JWST mirror operating environment in space. JWST mirror segment testing will continue for the next 18 months.


 楼主| 发表于 2010-03-13 17:54 | 显示全部楼层
2010 March 13

Centaurus A
Image Credit & Copyright: Tim Carruthers
Explanation: Only 11 million light-years away, Centaurus A is the closest active galaxy to planet Earth. Spanning over 60,000 light-years, the peculiar elliptical galaxy, also known as NGC 5128, is featured in this sharp color image. Centaurus A is apparently the result of a collision of two otherwise normal galaxies resulting in a fantastic jumble of star clusters and imposing dark dust lanes. Near the galaxy's center, left over cosmic debris is steadily being consumed by a central black hole with a billion times the mass of the Sun. As in other active galaxies, that process likely generates the radio, X-ray, and gamma-ray energy radiated by Centaurus A.
 楼主| 发表于 2010-03-14 13:06 | 显示全部楼层
2010 March 14

Binary Black Hole in 3C 75
Credit: X-Ray: NASA / CXC / D. Hudson, T. Reiprich et al. (AIfA);
Radio: NRAO / VLA/ NRL
Explanation: What's happening in the middle of this massive galaxy? There, two bright sources at the center of this composite x-ray (blue)/radio (pink) image are thought to be co-orbiting supermassive black holes powering the giant radio source 3C 75. Surrounded by multimillion degree x-ray emitting gas, and blasting out jets of relativistic particles the supermassive black holes are separated by 25,000 light-years. At the cores of two merging galaxies in the Abell 400 galaxy cluster they are some 300 million light-years away. Astronomers conclude that these two supermassive black holes are bound together by gravity in a binary system in part because the jets' consistent swept back appearance is most likely due to their common motion as they speed through the hot cluster gas at 1200 kilometers per second. Such spectacular cosmic mergers are thought to be common in crowded galaxy cluster environments in the distant universe. In their final stages the mergers are expected to be intense sources of gravitational waves.
 楼主| 发表于 2010-03-15 15:58 | 显示全部楼层
本帖最后由 jadiyd 于 2010-3-16 16:02 编辑

2010 March 15

Illuminated Cloud Trails Above Greece
Credit & Copyright: Chris Kotsiopoulos
Explanation: It may appear to be day, but it's night. Those wondrous orange streaks may appear to be rays from the setting Sun, but they're actually thin clouds illuminated by the Moon as they quickly streaked toward the distant horizon. The thick clouds on the far left may appear to have many layers, but actually they are just a few simple clouds captured on numerous separate exposures. What is surely true, though, is that the above time lapse image sequence was taken over two hours, about two weeks ago, in Sounio, Greece. Also, those really are star trails swirling around the north star Polaris on the upper right of the image. But what about the building in the foreground? It may appear to be a famous ancient structure, but it's actually a small deserted church built only last century.
 楼主| 发表于 2010-03-16 16:01 | 显示全部楼层
本帖最后由 jadiyd 于 2010-3-17 19:19 编辑

2010 March 16

Detailed View of a Solar Eclipse Corona
Credit & Copyright: Miloslav Druckmüller (Brno University of Technology), Martin Dietzel, Peter Aniol, Vojtech Rušin
Explanation: Only in the fleeting darkness of a total solar eclipse is the light of the solar corona easily visible. Normally overwhelmed by the bright solar disk, the expansive corona, the sun's outer atmosphere, is an alluring sight. But the subtle details and extreme ranges in the corona's brightness, although discernible to the eye, are notoriously difficult to photograph. Pictured above, however, using multiple images and digital processing, is a detailed image of the Sun's corona taken during the 2008 August total solar eclipse from Mongolia. Clearly visible are intricate layers and glowing caustics of an ever changing mixture of hot gas and magnetic fields. Bright looping prominences appear pink just above the Sun's limb. The next total solar eclipse will be in July but will only be visible in a thin swath of Earth crossing the southern Pacific Ocean and South America.


 楼主| 发表于 2010-03-17 19:18 | 显示全部楼层
2010 March 17

Phobos from Mars Express
Credit: G. Neukum (FU Berlin) et al., Mars Express, DLR, ESA
Explanation: Why is this small object orbiting Mars? The origin of Phobos, the larger of the two moons orbiting Mars, remains unknown. Phobos and Deimos appear very similar to C-type asteroids, yet gravitationally capturing such asteroids, circularizing their orbits, and dragging them into Mars' equatorial plane seems unlikely. Pictured above is Phobos as it appeared during last week's flyby of ESA's Mars Express, a robotic spacecraft that began orbiting Mars in 2003. Visible in great detail is Phobos' irregular shape, strangely dark terrain, numerous unusual grooves, and a spectacular chain of craters crossing the image center. Phobos spans only about 25 kilometers in length and does not having enough gravity to compress it into a ball. Phobos orbits so close to Mars that sometime in the next 20 million years, tidal deceleration will break up the rubble moon into a ring whose pieces will slowly spiral down and crash onto the red planet. The Russian mission Phobos-Grunt is scheduled to launch and land on Phobos next year.


 楼主| 发表于 2010-03-19 18:38 | 显示全部楼层
2010 March 18

Fermi Catalogs the Gamma-ray Sky
Credit: NASA, DOE, International Fermi LAT Collaboration
Explanation: What shines in the gamma-ray sky? The most complete answer yet to that question is offered by the Fermi Gamma-ray Space Telescope's first all-sky catalog. Fermi's sources of cosmic gamma-rays feature nature's most energetic particle accelerators, ultimately producing 100 MeV to 100 GeV photons, photons with more than 50 million to 50 billion times the energy of visible light. Distilled from 11 months of sky survey data using Fermi's Large Area Telescope (LAT), the 1,451 cataloged sources include energetic star burst galaxies and active galactic nuclei (AGN) far beyond the Milky Way. But within our own galaxy are many pulsars (PSR) and pulsar wind nebulae (PWN), supernova remnants (SNR), x-ray binary stars (HXB) and micro-quasars (MQO). Fermi's all sky map is shown centered on the Milky Way with the diffuse gamma-ray emission from the Galactic plane running horizontally through the frame. To locate the cataloged gamma-ray sources, just slide your cursor over the map. For now, 630 of the sources cataloged at gamma-ray energies remain otherwise unidentified, not associated with sources detected at lower energies.


 楼主| 发表于 2010-03-19 18:38 | 显示全部楼层
2010 March 19

The Seagull and the Duck
Image Credit & Copyright: Rogelio Bernal Andreo (Deep Sky Colors)
Explanation: Seen as a seagull and a duck, these nebulae are not the only cosmic clouds to evoke images of flight. But both are winging their way across this broad celestial landscape, spanning almost 7 degrees across planet Earth's night sky toward the constellation Canis Major. The expansive Seagull (upper left) is itself composed of two major cataloged emission nebulae. Brighter NGC 2327 forms the head with the more diffuse IC 2177 as the wings and body. Impressively, the Seagull's wingspan would correspond to about 250 light-years at an estimated distance of 3,800 light-years. At the lower right, the Duck appears much more compact and would span only about 50 light-years given its 15,000 light-year distance estimate. Blown by energetic winds from an extremely massive, hot star near its center, the Duck nebula is cataloged as NGC 2359. Of course, the Duck's thick body and winged appendages also lend it a more dramatic popular moniker -- Thor's Helmet.


 楼主| 发表于 2010-03-21 11:21 | 显示全部楼层
2010 March 20

Zodiacal Light Vs. Milky Way
Image Credit & Copyright: Daniel López
Explanation: Ghostly Zodiacal light, featured near the center of this remarkable panorama, is produced as sunlight is scattered by dust in the Solar System's ecliptic plane. In the weeks surrounding the March equinox (today at 1732 UT) Zodiacal light is more prominent after sunset in the northern hemisphere, and before sunrise in the south, when the ecliptic makes a steep angle with the horizon. In the picture, the narrow triangle of Zodiacal light extends above the western horizon and seems to end at the lovely Pleiades star cluster. Arcing above the Pleiades are stars and nebulae along the plane of our Milky Way Galaxy. Recorded on March 10 from Teide National Park on the island of Tenerife, the vista is composed of 4 separate pictures spanning over 180 degrees.
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