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[视图资料] Astronomy Picture of the Day-2009-每日天文一图第三季(updating)

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 楼主| 发表于 2009-11-25 14:59 | 显示全部楼层
本帖最后由 jadiyd 于 2009-12-30 18:25 编辑

2009 November 25

All-Sky Milky Way Panorama
Credit & Copyright: Axel Mellinger (Central Mich. U)
Explanation: If you could go far away from the Earth and look around the entire sky -- what would you see? Such was the goal of the All-Sky Milky Way Panorama 2.0 project of Axel Mellinger. Presented above is the result: a digital compilation of over 3,000 images comprising the highest resolution digital panorama of the entire night sky yet created. An interactive zoom version, featuring over 500 million pixels, can be found here. Every fixed astronomical object visible to the unaided eye has been imaged, including every constellation, every nebula, and every star cluster. Moreover, millions are individual stars are also visible, all in our Milky Way Galaxy, and many a thousand times fainter than a human can see. Dark filaments of dust lace central band of our Milky Way Galaxy, visible across the image center. The satellite galaxies Large and Small Magellanic Clouds are visible on the lower right. This was not the first time Dr. Mellinger has embarked on such a project: the results of his first All-Sky Milky Way Panorama Project, taken using photographic film, are visible here.

说明:如果你能沿着地球走足够远,你就能够看到整个天空,那么你将会看到什么?这就是Axel Mellinger全天银河系全景2.0版本项目。上面影像中的结果是用超过3,000张影像经过数码合成形成了迄今为止最高清晰的数码全黑夜影像。在这里还可以找到一张交互式放大版本,合成了超过5亿帧影像而得。在影像里可以肉眼看到每一个天体,包括每个星座,每块星云以及每个恒星团。更甚的是,在我们银河系内还可以看到数百万颗单独的恒星,以及许多比人肉眼所及远1,000倍的恒星。黑暗的尘埃带形成了我们银河系的中心带,可以看到尘埃带穿过了影像的中央。银河系的卫星星系大、小麦哲伦星云出现在影像的右下方。这已经不是Mellinger博士第一次从事此项工程了:第一次全天银河系全景影像工程拍摄了数码胶卷,可以在这里找到。

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发表于 2009-11-25 20:11 | 显示全部楼层
楼主辛苦
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 楼主| 发表于 2009-11-26 20:06 | 显示全部楼层
2009 November 26

M78 Wide Field
Credit & Copyright: Thomas V. Davis (tvdavisastropix.com)
Explanation: Interstellar dust clouds and glowing nebulae abound in the fertile constellation of Orion. One of the brightest, M78, is centered in this colorful, wide field view, covering an area north of Orion's belt. At a distance of about 1,500 light-years, the bluish reflection nebula is around 5 light-years across. Its tint is due to dust preferentially reflecting the blue light of hot, young stars. Reflection nebula NGC 2071 is just to the left of M78. To the right of M78 and much more compact in appearance, the intriguing McNeil's Nebula is a recently recognized variable nebula associated with the formation of a sun-like star. The remarkably deep exposure also brings out the region's faint but pervasive reddish glow of atomic hydrogen gas.

说明星际尘埃云以及炽热的星云充满了星云富集的猎户座M78是其中最明亮的一个,它位于这张色彩绚丽,视场宽广的影像中央,影像中还拍摄到了猎户座腰带星蓝色反射星云距离我们大约1,500光年远,大约有5光年宽。由于尘埃优先反射炽热年轻恒星发出的蓝光,从而形成了星云的色彩。反射星云NGC2071就位于M78的左侧。在M78的右侧,看上去更致密的是迷人的麦克尼尔星云,最近它被认为是一个可变星云,与一颗类似太阳一样的恒星诞生有关。这张壮观的深空影像还显现了该区域较为昏暗但又到处弥漫着的由氢原子释放出的泛红色光芒。


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 楼主| 发表于 2009-11-28 19:07 | 显示全部楼层

2009 年 11 月 27 日


NGC1097的喷流

影像提供及版权Robert Gendler

说明:神秘莫测的旋涡星系NGC1097距离我们大约4,500万光年远,位于南方的天炉座内。有一个伴星系出现在影像中央的左下方,看上去它好像被包裹在星系的旋臂中一样,但这还不是NGC1097最特殊的特征。反而,在这张深空曝光影像里显示了昏暗而又神秘喷流的线索,很容易从影像中看到从明亮的旋臂向右下方喷出。事实上,在这张NGC1097光学影像中可以辨认4道喷流。喷流痕迹以星系核为中心呈现出一个X字样,但也可能是这个巨大旋涡星系在过去捕捉到一个较小的星系的陈旧痕迹。作为一个塞弗特星系NGC1097星系核附近也拥有一个大质量黑洞

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 楼主| 发表于 2009-11-28 19:07 | 显示全部楼层
本帖最后由 jadiyd 于 2009-12-30 18:25 编辑

2009 November 28

Annapurna Star Trails
Credit & Copyright: Wang Jinglei, Jia Hao
Explanation: In myth, Atlas holds up the heavens. But in this moonlit mountainscape, peaks of the Himalayan Annapurna Range appear to prop up the sky as seen from Ghandruk, Nepal. From left to right the three main peaks are Annapurna South (7,219 meters), Hiunchuli (6,441 metes), and Machapuchare (6,995 meters). Of course the mountains are moving not the stars, the Earth's rotation about its axis causing the concentric star trails recorded in the time exposure. Positioned above Annapurna South, the North Celestial Pole is easily identified as the point at the center of all the star trail arcs. The star Polaris, also known as the North Star, made the very short and bright arc closest to the North Celestial Pole.
说明:神话里阿特拉斯支撑着天空。但是在这片月光照亮了的山脉景色里,从尼泊尔的Ghandruk看去,喜马拉雅山脉的安娜普纳群峰也像支撑着天空一样。从左至右,三座主峰分别是安娜普纳南峰(7,219),Hiunchuli (6,441 ),以及鱼尾峰 (6,995 )。当然,山峰在移动而不是天上的星星,在这张长时间曝光拍摄到的影像里,地球以轴自转形成了同心圆的星象迹线。安娜普纳南峰上空所指的方向就是北天极,很容易在星象迹线的中央圆点找到。北极星就是那颗距离北天极最近、最亮并且形成最短弧的恒星。
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 楼主| 发表于 2009-11-29 22:06 | 显示全部楼层
本帖最后由 jadiyd 于 2009-12-30 18:24 编辑

2009 November 29

Ancient Layered Hills on Mars
Credit: Malin Space Science Systems, MOC, MGS, JPL, NASA
Explanation: Is this a picture of Mars or Earth? Oddly enough, it is a picture of Mars. What may appear to some as a terrestrial coastline is in fact a formation of ancient layered hills and wind-blown sand on Mars. The above-pictured region spans about three kilometers in Schiaparelli Crater. What created the layers of sediment is still a topic of research. Viable hypotheses include ancient epochs of deposit either from running water or wind-blown sand. Winds and sandstorms have smoothed and eroded the structures more recently. The "water" that appears near the bottom is actually dark colored sand. The image was taken with the Mars Global Surveyor spacecraft that operated around Mars from 1996-2006 and returned over 200,000 images.

说明:这张照片拍摄的是火星还是地球上?令人奇怪的是,这是一张火星照片.表面看上去就像是崎岖的海岸线,实际上这是火星古代形成的层状山丘以及被风吹出的沙子所组成的地貌.上面的影像拍摄的区域位于Schiaparelli 陨石坑内,宽约3公里.是什么造成了沉积物的层状结构仍然是研究的一个课题.可以预见的假设源自古代沉淀地貌,或者是水流形成或者是风沙.最近火星上的风暴侵蚀了它们并且让其外观变得平滑.这里所看到的"水"实际上是位于底部颜色较深的沙土.影像是由火星全球勘测飞船拍摄,从1996-2006年间绕火星飞行的飞船拍摄并发回了20多万张影像

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 楼主| 发表于 2009-11-30 13:18 | 显示全部楼层
本帖最后由 jadiyd 于 2009-12-30 18:24 编辑

2009 November 30

Bright Sun and Crescent Earth from the Space Station
Credit: STS-129 Crew, NASA
Explanation: This was just one more breathtaking view from the International Space Station. The Sun, a crescent Earth, and the long arm of a solar panel were all visible outside a window when the Space Shuttle Atlantis visited the orbiting outpost last week. Reflections from the window and hexagonal lens flares from the camera are superposed. The space shuttle landed Friday after a successful 10 day mission to expand and resupply the ISS. Numbered STS-129, the space shuttle mission returned astronaut Nicole Stott to Earth from her stay on the ISS as a Flight Engineer in the Expedition 20 and21 crews.

说明:这仅仅是从国际空间站上看到的又一幅惊人画面而已。太阳,地球以及长长的太阳能电池板都出现亚特兰蒂斯号航天飞机的窗外,上周航天飞机访问了这个地球的前哨站。窗户的反射光和六边形镜头眩光相互叠加。航天飞机在上周五安全着陆,成功地完成了为期10天对ISS的扩展与补给使命。此次使命被命名为STS-129,将宇航员Nicole Stott接回地球,她作为随机工程师成为了ISS2021远征队队员。

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 楼主| 发表于 2009-12-01 20:07 | 显示全部楼层
2009 December 1

NGC 6992: Filaments of the Veil Nebula
Credit & Copyright: Daniel Lopez (Observatorio del Teide)
Explanation: Wisps like this are all that remain visible of a Milky Way star. About 7,500 years ago that star exploded in a supernova leaving the Veil Nebula, also known as the Cygnus Loop. At the time, the expanding cloud was likely as bright as a crescent Moon, remaining visible for weeks to people living at the dawn of recorded history. Today, the resulting supernova remnant has faded and is now visible only through a small telescope directed toward the constellation of the Swan (Cygnus). The remaining Veil Nebula is physically huge, however, and even though it lies about 1,400 light-years distant, it covers over five times the size of the full Moon. In images of the complete Veil Nebula, studious readers should be able to identify the above filaments on the lower left. The above image is a mosaic from the 2.5-meter Isaac Newton Telescope at Roque de los Muchachos Observatory in the Canary Islands.

说明:这些细丝就是一颗银河系恒星所留下的可见遗迹。大约在7,500年前,一颗恒星发生超新星爆炸从而留下了面纱星云,也被称为天鹅圈。在当时,扩张的星云如同新一样明亮,历史上有记载,对于那时候的人们来说该星云在黎明前持续数周可见。如今,超新星遗迹已经暗淡下来,只能通过小望远镜朝天鹅座方向看去才能看到它。遗留下来的面纱星云实际上非常巨大,即使距离我们大约1,400光年远,它在天空中覆盖的大小仍然是满月大小的5倍还多。在这张完整面纱星云的影像中,认真细致的读者将能确定影像左下方的丝状物质。上面的影像是由直径为2.5艾萨克.牛顿望远镜拍摄,该望远镜位于加那利群岛上的Roque de los Muchachos 天文台内。

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 楼主| 发表于 2009-12-02 21:31 | 显示全部楼层
2009 December 2

Dust Sculptures in the Rosette Nebula
Credit & Copyright: John Ebersole
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 2237, 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 above image was taken in very specific colors of Sulfur (shaded red), Hydrogen (green), and Oxygen (blue). 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 the Unicorn (Monoceros).

说明:是什么形成了玫瑰星云内的宇宙尘埃?它以其美丽的整体外观而闻名,玫瑰星云还被称为NGC2237, 其部分星云即使在足够近的特写镜头下也一样美丽.可以看到上面影像里,由黑暗尘埃气体组成的球状体正在慢慢地被附近大质量恒星放射出的光和恒星风所侵蚀.只要经过足够长的时间,分子气体云组成的球状体将会形成恒星和行星.上面的影像是透过特殊颜色拍摄的,这些色彩分别由(红色),(绿色),(蓝色)放射出.玫瑰星云内覆盖大约50光年,距离我们大约4,500光年远,用小望远镜朝麒麟座方向看就能找到它.

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 楼主| 发表于 2009-12-03 19:53 | 显示全部楼层
2009 December 3

Polar Ring Galaxy NGC 660
Credit & Copyright: Immo Gerber and Dietmar Hager (TAO)
Explanation: NGC 660 lies near the center of this intriguing field of galaxies swimming within the boundaries of the constellation Pisces. Over 20 million light-years away, its peculiar appearance marks it as a polar ring galaxy. A rare galaxy type, polar ring galaxies have a substantial population of stars, gas, and dust orbiting in rings nearly perpendicular to the plane of a flat galactic disk. The bizarre configuration could have been caused by the chance capture of material from a passing galaxy by the disk galaxy, with the captured debris strung out in a rotating ring. Polar Ring galaxies can be used to explore the shape of the galaxy's otherwise unseen dark matter halo by calculating the dark matter's gravitational influence on the rotation of the ring and disk. Broader than the disk, NGC 660's ring spans about 40,000 light-years.

说明:NGC660位于这片迷人场景的中央,位于双鱼座.该星系距离我们2,000多万光年,其特殊的外观说明了它是一个极环星系.作为一个相对罕见的类型,极环星系内具有相对数目较多的恒星,气体以及尘埃围绕在垂直于星系盘面的环面上运动.奇异的星系构造可能是偶然情况下从附近通过的星系盘面上捕捉物质而成,捕捉到的碎片延展成一个旋转的环.极环星系被利用来探索星系的形状,同时还有暗物质引力作用在环状的光环和盘面上计算出来的不可见暗物质晕.NGC660的光环比星系盘面更宽,大约覆盖了4万光年.

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 楼主| 发表于 2009-12-04 17:40 | 显示全部楼层
2009 December 4

The Double Cluster
Credit & Copyright: Neil Fleming
Explanation: A lovely starfield in the heroic northern constellation Perseus holds this famous pair of open or galactic star clusters, h and Chi Perseii. Also cataloged as NGC 869 (right) and NGC 884, both clusters are about 7,000 light-years away and contain stars much younger and hotter than the Sun. Separated by only a few hundred light-years, the clusters' ages based on their individual stars are similar - evidence that they were likely a product of the same star-forming region. Always a rewarding sight in binoculars, the Double Cluster is even visible to the unaided eye from dark locations. Star colors (and spikes) are enhanced in this beautiful, wide field, telescopic image.

说明:在北方英仙座内的一片可爱星场里拥有着一对著名的疏散星团, 英仙座h和χ.双星团还被命名为NGC869(右侧)NGC884,它们距离我们大约7,000光年远,其所包含的恒星比我们太阳更年轻,更为炽热.两个星团相距仅仅数百光年远,星团的年龄基于所含的个体恒星,恒星个体间比较类似,因为它们是同一恒星形成区域内的共同产物.通常利用双筒望远镜才能看到该双星团,但是在黑暗地区也能看到它.在这张美丽的广域望远镜影像里,恒星的色彩(以及铆钉状的效果)被加强.

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 楼主| 发表于 2009-12-06 16:01 | 显示全部楼层
本帖最后由 jadiyd 于 2009-12-30 18:23 编辑

2009 December 6

The Magnificent Tail of Comet McNaught
Credit & Copyright: Robert H. McNaught
Explanation: Comet McNaught, the Great Comet of 2007, was the brightest comet of the last 40 years. Its spectacular tail spread across the sky and was breathtaking to behold from dark locations for many Southern Hemisphere observers. The head of the comet remained quite bright and was easily visible to even city observers without any optical aide. Part of the spectacular tail was visible just above the horizon after sunset for many northern observers as well. Comet C/2006 P1 (McNaught), which reached an estimated peak brightness of magnitude -6 (minus six), was caught by the comet's discoverer in the above image soon after sunset in 2007 January from Siding Spring Observatory in Australia. The robotic Ulysses spacecraft fortuitously flew through Comet McNaught's tail and found, unexpectedly, that the speed of the solar wind dropped significantly.
说明:麦克诺特彗星--2007年最为壮观的彗星,它也是过去40年里最亮的彗星。它壮观的彗尾划过了天空,此景对于许多处于黑暗地区的南半球天文观测者来说异常壮观。彗星的头部明亮可见,甚至城市里的观测者在没有任何光学辅助设备的帮助下仍很容易看到。日落之后,在地平线的上方还能看到部分壮观的彗尾C/2006 P1彗星(麦克诺特)的亮度,据估计达到了最高值-6上面这张影像彗星的发现者拍摄的,在20071月日落时分影像拍摄于澳大利亚赛丁泉天文台尤利西斯飞船幸运地飞过了麦克诺特彗星的彗尾,意外地发现了太阳风强度显著下降的速率。
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发表于 2009-12-07 00:07 | 显示全部楼层
再顶楼主,我几乎每天必看
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 楼主| 发表于 2009-12-08 18:22 | 显示全部楼层
2009 December 8

Ice Moon Tethys from Saturn-Orbiting Cassini
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
Explanation: What processes formed the unusual surface of Saturn's moon Tethys? To help find out, NASA sent the robotic Cassini spacecraft right past the enigmatic ice moon in 2005. Pictured above is one of the highest resolution images of an entire face of Tethys yet created. The pervasive white color of Tethys is thought to be created by fresh ice particles continually falling onto the moon from Saturn's diffuse E-ring -- particles expelled by Saturn's moon Enceladus. Some of the the unusual cratering patterns on Tethys remain less well understood, however. Close inspection of the above image of Tethys' south pole will reveal a great rift running diagonally down from the middle: Ithaca Chasma. A leading theory for the creation of this great canyon is anchored in the tremendous moon-wide surface cracking that likely occurred when Tethys' internal oceans froze. If so, Tethys may once have harbored internal oceans, possibly similar to the underground oceans some hypothesize to exist under the surface of Enceladus today. Might ancient life be frozen down there?

说明:土卫三经历了什么过程从而形成了如此不寻常的表面呢?为了帮助找到答案,NASA派遣了卡西尼飞船,在2005年飞越了这颗神秘的冰封卫星。上面的影像是迄今为止拍摄土卫三整个表面最高清影像之一。土卫三表面到处弥漫的白色被认为是由新冰晶造成,而这些冰晶持续不断地从土星E掉落到卫星的表面而部分晶体则由土卫二喷发出。然而,土卫三表面上一些异常的陨击形状仍然缺乏很好的解释。仔细检查上面影像土卫三南极附近,就会发现有一道巨大的裂缝,从中央斜对角地向下:它被命名为伊萨卡峡谷。形成这个巨大峡谷的主要原理可能是当土卫三内部海洋结冰时形成了如月表宽的巨大裂缝。如果真是那样,土卫三曾经可能存在内部海洋,可能与今天猜测土卫二表面下存在着地下海洋一样。是否会有远古生命被冻结在下面呢?

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 楼主| 发表于 2009-12-09 19:59 | 显示全部楼层
2009 December 9

HUDF Infrared: Dawn of the Galaxies
Credit: NASA, ESA, G. Illingworth (UCO/Lick & UCSC), R. Bouwens (UCO/Lick & Leiden U.), & the HUDF09 Team
Explanation: When did galaxies form? To help find out, the deepest near-infrared image of the sky ever has been taken of the same field as the optical-light Hubble Ultra Deep Field (HUDF) in 2004. The new image was taken this summer by the newly installed Wide Field Camera 3 on the refurbished Hubble Space Telescope. Faint red smudges identified on the above image likely surpass redshift 8 in distance. These galaxies therefore likely existed when the universe was only a few percent of its present age, and may well be members of the first class of galaxies. Some large modern galaxies make a colorful foreground to the distant galaxies. Analyses by the HUDF09 team indicate that at least some of these early galaxies had very little interstellar dust. This early class of low luminosity galaxies likely contained energetic stars emitting light that transformed much of the remaining normal matter in the universe from a cold gas to a hot ionized plasma.
说明:星系在何时形成?为了帮助寻找答案,天空中最深空近红外影像被拍摄下来,与2004哈勃超深空光学影像相同,拍摄了同一区域。新影像是由今年夏天新安装的广域相机3拍摄,该相机位于今夏经过翻修了的哈勃太空望远镜上。在上面影像中能够辨别的昏暗红色斑点宇宙红移已经超过了数值8。因此这些星系在宇宙刚形成不久时就已经存在,有许多是第一类星系。一些大型近代星系相对应遥远星系来说,它们成为了美丽的前景。通过HUDF09小组的分析表明,至少在一些早期星系内,具有极少的星际尘埃。这类早期低光度星系中可能拥有高能恒星,它们发出的光能将宇宙中遗留下来的普通物质发生变化,能将冷气体激发为电离的炽热等离子体
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 楼主| 发表于 2009-12-10 16:32 | 显示全部楼层
本帖最后由 jadiyd 于 2009-12-30 18:23 编辑

2009 December 10

The Colors of IC 1795
Credit & Copyright: Don Goldman
Explanation: This colorful cosmic portrait features glowing gas and dark dust clouds in IC 1795, a star forming region in the northern constellation Cassiopeia. The nebula's colors were created by adopting the Hubble false-color palette for mapping narrow emission from oxygen, hydrogen, and sulfur atoms to blue, green and red colors, and further blending the data with images of the region recorded through broadband filters. Not far on the sky from the famous Double Star Cluster in Perseus, IC 1795 is itself located next to IC 1805, the Heart Nebula, as part of a complex of star forming regions that lie at the edge of a large molecular cloud. Located just over 6,000 light-years away, the larger star forming complex sprawls along the Perseus spiral arm of our Milky Way Galaxy. At that distance, this picture would span about 70 light-years across IC 1795.

说明:这张彩色宇宙影像突出了IC1795炽热的气体和黑暗尘埃,是北方仙后座内一个恒星形成区域.星云的色彩由哈勃自适应假色调色系统通过窄带滤波器拍摄,从而得到氧原子,氢原子,以及硫原子发射出的蓝色,绿色以及红色辉光,影像中还混合了该区域通过宽带滤波器拍摄到的影像数据.IC1795距离英仙座内的著名双星团不远,紧挨着IC1805(心脏星云),是一片复杂恒星诞生区域的一部分,处于大分子云的边缘.距离我们大约6,000多光年远,较大的恒星形成区域缠绕在我们银河系的英仙旋臂上.在这个距离上估计,这张照片大约在IC1795内覆盖70光年.

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 楼主| 发表于 2009-12-11 21:19 | 显示全部楼层
2009 December 11

Messier Craters in Stereo
Credit Apollo 11, NASA; Stereo Image by Patrick Vantuyne
Explanation: Many bright nebulae and star clusters in planet Earth's sky are associated with the name of astronomer Charles Messier, from his famous 18th century catalog. His name is also given to these two large and remarkable craters on the Moon. Standouts in the dark, smooth lunar Sea of Fertility or Mare Fecunditatis, Messier (left) and Messier A have dimensions of 15 by 8 and 16 by 11 kilometers respectively. Their elongated shapes are explained by an extremely shallow-angle trajectory followed by the impactor, moving left to right, that gouged out the craters. The shallow impact also resulted in two bright rays of material extending along the surface to the right, beyond the picture. Intended to be viewed with red/blue glasses (red for the left eye), this striking stereo picture of the crater pair was recently created from high resolution scans of two images (AS11-42-6304, AS11-42-6305) taken during the Apollo 11 mission to the moon.

说明:在地球夜空中有许多明亮的星云以及恒星团都与著名的天文学家查尔斯.梅西耶的名字有关,都出自于18世纪他编写的著名星云星团表.他的名字还被用来命名了月球上两个巨大而又显著的环形山.在黑暗而又平滑的广阔月海或者是黑暗地区异常显著突出,梅西耶()和梅西耶A相对大小约15公里*8公里,16公里*11公里.它们延伸的形状被解释为发生碰撞发时,冲击物以一个极度倾斜的轨道从左向右撞上月面, ,从而凿出了一个陨石坑.这个较浅的环形山还造成了两道明亮的光线,从月球表面一直延伸到右侧,一直到影像外.红蓝眼镜观看这张影像,这对壮观的陨石坑立体影像是由高清晰影像(AS11-42-6304,AS11-42_6305)扫描而得,影像是阿波罗11号在去往月球的任务期间拍摄。

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 楼主| 发表于 2009-12-12 19:06 | 显示全部楼层
本帖最后由 jadiyd 于 2009-12-30 18:22 编辑

2009 December 12

Geminid Meteor over Monument Valley
Credit & Copyright: Wally Pacholka (AstroPics.com, TWAN) Explanation: The Geminids are expected to put on a good show this year. Created as planet Earth sweeps through dusty debris from extinct comet Phaethon, the annual Geminid meteor shower is predicted to peak on December 14th, around 0510 UT (12:10am EST). With better viewing for northern hemisphere observers, pictures of Geminids streaking through the night could include wintery landscapes, like this snow-tinged image of a 2007 Geminid meteor over buttes of the Monument Valley region in the southwestern US. The meteor streak points back to the constellation Gemini and the shower's radiant point, just off the upper left edge of the scene. Along with Rigel, the sword and belt stars of Orion are at the upper right. Near the eastern horizon are bright stars Procyon (left) and Sirius. The two buttes at the far left are known as The Mittens - clearly a reminder that if you want to watch a meteor shower on a cold December night, wearing mittens would be a good idea.

说明:今年的双子座流星雨将异常精彩。当地球通过由法尔松彗星留下来的尘埃碎片时就形成了一年一度的双子座流星雨,流星雨的高峰期预计将在1214达到,大约是在世界时间510分左右(美国东部时间1210分)。对于北半球的观测者来说将有较好的观看视野,夜晚拍摄到的双子座流星雨轨迹影像里应包括冬天的美景,就像这张在美国西南部纪念碑山谷上空拍摄到的2007年双子座流星雨影像一样,影像中具有白雪覆盖。流星轨迹向后指向双子座也就是流星雨的辐射点,辐射点就位于影像的左上边缘外侧。与参宿七一起,猎户座宝剑与腰带恒星都位于影像的右上方。接近东方地平线的是明亮恒星南河三(左侧)与天狼星。影像最左侧是两座孤山,被称为连指手套。温馨提示,如果你想在寒冷的12月夜晚观看流星雨,戴上连指手套将会是一个不错的选择。


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 楼主| 发表于 2009-12-13 19:21 | 显示全部楼层
本帖最后由 jadiyd 于 2009-12-30 18:22 编辑

2009 December 13

Crescent Neptune and Triton
Credit: Voyager 2, NASA
Explanation: Gliding silently through the outer Solar System, the Voyager 2 spacecraft camera captured Neptune and Triton together in crescent phase in 1989. The above picture of the gas giant planet and its cloudy moon was taken from behind just after closest approach. It could not have been taken from Earth because Neptune never shows a crescent phase to sunward Earth. The unusual vantage point also robs Neptune of its familiar blue hue, as sunlight seen from here is scattered forward, and so is reddened like the setting Sun. Neptune is smaller but more massive than Uranus, has several dark rings, and emits more light than it receives from the Sun.

说明:随着旅行者2号飞船静静地飞过太阳系的外层空间,在1989年它的相机捕捉到了海王星海卫一共同出现新月相位的影像。上面这张气态巨行星以及云雾笼罩的卫星影像是由飞船在飞过最近点时拍摄。它不可能在地球上拍摄到,因为在面朝太阳的地球上永远也不可能看到具有相位的海王星。在这异常有利的位置上还拍摄到了海王星那有名的蓝色调,从这里所看到的太阳光是被散射过来的,因此看上去有些微微变红就像日落的色彩一样。海王星天王星体积较小,但是质量更大,周围有几道暗光环,它发射出的光线比从太阳光中吸收的光线还多。


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发表于 2009-12-14 16:44 | 显示全部楼层
338楼的陨石坑  高度能到多少?1000米?  据说月球上没有高山,只有深坑?
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 楼主| 发表于 2009-12-15 20:46 | 显示全部楼层
2009 December 15

A Fading Moonset Over Hong Kong
Credit & Copyright: Wah!
Explanation: Do stars appear dimmer when nearer the horizon? Yes -- atmospheric air absorbs and reradiates light, so that the greater the airmass through which one peers, the fainter an object will appear. Pictured above in a multi-frame image, stars, the planet Jupiter, and even the Moon show the horizon-dimming effects of Earth's nearly-transparent atmosphere. The image was taken in the evening about three weeks ago over Hong Kong, China. The brightest streak near the center is the setting Moon, while intermittent thin clouds sometimes dispersed moonlight into a larger halo. Jupiter sets just to the Moon's right. The dim steaks cutting across the image horizontally were caused by passing airplanes. The bright strange multi-pronged streak over the house is a helicopter taking off. An astute observer will also notice faint rays emanating from near the horizon. Their cause is unknown, but may be crepuscular rays caused by the Sun shining through gaps in thick clouds.

说明:星星在接近地平线附近时会变得更暗吗?当然,因为大气层中的空气吸收以及再辐射光线,所以同一星体再穿过较厚气团时就会变暗。在上面这张多帧影像里,恒星,木星甚至是月球在地球近似透明的大气层下显现出了地平线昏暗效应。影像是三周前在中国香港的夜晚拍摄。在影像中央附近出现的最亮条纹就是正在落山的月球,而间歇性飘过的薄云驱散了月光形成了一个大光晕。木星就位于月球的右侧。有昏暗的条纹以水平方向切割了影像,那是通过上空的飞机。而在房子上空出现的明亮而又奇怪的多点条纹是一架正在起飞的直升机。具有洞察敏锐的观众还会发现在地平线附近出现的昏暗射线。原因未知,有可能是太阳光透过厚厚大气层内的空隙形成的曙暮辉

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 楼主| 发表于 2009-12-15 20:48 | 显示全部楼层
回复 341# bjnr

本帖只作每日发图所用~
如需讨论请另行开贴~
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 楼主| 发表于 2009-12-16 22:08 | 显示全部楼层
2009 December 16

Comet Hyakutake Passes the Earth
Credit & Copyright: Doug Zubenel (TWAN)
Explanation: In 1996, an unexpectedly bright comet passed by planet Earth. Discovered less than two months before, Comet C/1996 B2 Hyakutake came within only 1/10th of the Earth-Sun distance from the Earth in late March. At that time, Comet Hyakutake, dubbed the Great Comet of 1996, became the brightest comet to grace the skies of Earth in 20 years. During its previous visit, Comet Hyakutake may well have been seen by the stone age Magdalenian culture, who 17,000 years ago were possibly among the first humans to live in tents as well as caves. Pictured above near closest approach as it appeared on 1996 March 26, the long ion and dust tails of Comet Hyakutake are visible flowing off to the left in front of a distant star field that includes both the Big and Little Dippers. On the far left, the blue ion tail appears to have recently undergone a magnetic disconnection event. On the far right, the comet's green-tinted coma obscures a dense nucleus of melting dirty ice estimated to be about 5 kilometers across. A few months later, Comet Hyakutake began its long trek back to the outer Solar System. Because of being gravitationally deflected by massive planets, Comet Hyakutake is not expected back for about 100,000 years.

说明1996年一颗异常明亮的彗星通过了地球。发现该彗星仅不到两个月的时间,C/1996B2百武彗星3月末距离地球仅仅1/10日地距离。在那时候,百武彗星也为成为1996年大彗星,称为近20年来划过天空最亮的彗星。上一次见到百武彗星可能是在石器时代马达利尼亚人文化,也就是在1.7万年前,第一批人类居住在类似帐篷一样的洞穴内。上面的影像是在1996326拍摄,当时彗星临近近地点,百武彗星长长的离子尾和尘埃尾一直延伸到影像的左侧,那里正是遥远星场的前方,其中还包括大小北斗星。影像最左侧,蓝色的离子尾看上去正在经历一次磁性断尾事件。位于影像最右侧的是彗星的绿色彗发,它是一团融化了的脏冰所组成的致密模糊彗核,估计直径大约有5公里宽。几个月之后,百武彗星开始返回外太阳系。因为经过大行星引力的偏离作用,百武彗星将在10万多年后才可能返回地球。

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 楼主| 发表于 2009-12-17 20:42 | 显示全部楼层
2009 December 17

Mojave Desert Fireball
Credit & Copyright: Wally Pacholka (AstroPics.com, TWAN)
Explanation: Monstrously bright, this fireball meteor lit up the Mojave Desert sky Monday morning, part of this year's impressive Geminid meteor shower. Seen toward the southwest over rock formations near Victorville, California, a more familiar celestial background was momentarily washed out by the meteor's flash. The background includes bright star Sirius at the left, and Aldebaran and the Pleaides star cluster at the right side of the image. The meteor itself blazes through the constellation Orion. Its greenish trail begins just left of a yellow-tinted Betelgeuse and points back to the shower's radiant in Gemini, just off the top of the frame. A rewarding catch for photographer Wally Pacholka, the spectacular image is one of over 1500 frames that he reports captured 48, mostly faint, Geminid meteors.

说明:极度明亮的火流星在周一凌晨划过了莫哈韦沙漠上的夜空,这是今年精彩双子座流星雨的一部分。在美国加利福尼亚州Victorville附近的岩层上空,朝西南方向看去,熟悉的天空背景被流星亮闪短暂淹没。背景中的恒星从左到右包括明亮的天狼星毕宿五,以及右边的昴星团。流星划过了猎户座。它那绿色的流星迹尾巴开始从泛黄色的参宿四左侧开始,其反向辐射点正好指向双子座流星雨的辐射点,辐射点就位于影像顶端外。作为摄影师Wally Pacholka的奖赏,这张壮观的影像是他拍摄1500多张影像捕捉到48颗流星中最为壮观的一张,大多数拍摄到的双子座流星都比较昏暗。


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 楼主| 发表于 2009-12-19 15:14 | 显示全部楼层
本帖最后由 jadiyd 于 2009-12-30 18:22 编辑

2009 December 19

Aurora Shimmer, Meteor Flash
Credit & Copyright: Bjørnar G. Hansen,
Explanation: Northern Lights, or aurora borealis, haunted skies over the island of Kvaløya, near Tromsø Norway on December 13. This 30 second long exposure records their shimmering glow gently lighting the wintery coastal scene. A study in contrasts, it also captures the sudden flash of a fireball meteor from December's excellent Geminid meteor shower. Streaking past familiar stars in the handle of the Big Dipper, the trail points back toward the constellation Gemini, off the top of the view. Both aurora and meteors occur in Earth's upper atmosphere at altitudes of 100 kilometers or so, but aurora are caused by energetic charged particles from the magnetosphere, while meteors are trails of cosmic dust.

说明:如果你在每天的同一时间走到户外,拍摄一张照片,其中要有太阳,那么太阳的运动会是怎么样?需要伟大的计划和努力才能得到如此的一系列影像。太阳的8字形路径说明了太阳全年所走过的路线,这也被称为地球仪8字曲线。这周二也就是北半球的冬至日,太阳将会出现在8字曲线的最底层。地球仪8字曲线在不同的纬度下所形成的曲线会略有不同,同样不同日子形成的8字曲线也会不同。然而需要更伟大的计划与努力才能得到一系列日全食影像。上面的影像就是这样一张日全食8字形曲线图,或者说被称为Tutulemma,这是一个专业术语,由拍摄者利用土耳其语言里关于日食的文字组成。合成影像是2005年在土耳其开始拍摄的。这一系列影像的底版来自于2006329,在土耳其赛德拍摄的日全食影像。影像中还拍摄到了日全食期间的金星,就位于影像的左下方。

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发表于 2009-12-20 12:54 | 显示全部楼层
这么美の图,还配字说明,楼主辛苦了[:a15:]
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 楼主| 发表于 2009-12-20 17:50 | 显示全部楼层
本帖最后由 jadiyd 于 2009-12-30 18:21 编辑

2009 December 20

Tutulemma: Solar Eclipse Analemma
Credit & Copyright: Cenk E. Tezel and Tunç Tezel (TWAN)
Explanation: If you went outside at exactly the same time every day and took a picture that included the Sun, how would the Sun appear to move? With great planning and effort, such a series of images can be taken. The figure-8 path the Sun follows over the course of a year is called an analemma. This coming Tuesday, the Winter Solstice day in Earth's northern hemisphere, the Sun will be at the bottom of the analemma. Analemmas created from different latitudes would appear at least slightly different, as well as analemmas created at a different time each day. With even greater planning and effort, the series can include a total eclipse of the Sun as one of the images. Pictured is such a total solar eclipse analemma or Tutulemma - a term coined by the photographers based on the Turkish word for eclipse. The composite image sequence was recorded from Turkey starting in 2005. The base image for the sequence is from the total phase of a solar eclipse as viewed from Side, Turkey on 2006 March 29. Venus was also visible during totality, toward the lower right.

说明:如果你在每天的同一时间走到户外,拍摄一张照片,其中要有太阳,那么太阳的运动会是怎么样?需要伟大的计划和努力才能得到如此的一系列影像。太阳的8字形路径说明了太阳全年所走过的路线,这也被称为地球仪8字曲线。这周二也就是北半球的冬至日,太阳将会出现在8字曲线的最底层。地球仪8字曲线在不同的纬度下所形成的曲线会略有不同,同样不同日子形成的8字曲线也会不同。然而需要更伟大的计划与努力才能得到一系列日全食影像。上面的影像就是这样一张日全食8字形曲线图,或者说被称为Tutulemma,这是一个专业术语,由拍摄者利用土耳其语言里关于日食的文字组成。合成影像是2005年在土耳其开始拍摄的。这一系列影像的底版来自于2006329,在土耳其赛德拍摄的日全食影像。影像中还拍摄到了日全食期间的金星,就位于影像的左下方。

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 楼主| 发表于 2009-12-22 16:15 | 显示全部楼层
本帖最后由 jadiyd 于 2009-12-30 18:21 编辑

2009 December 22

Planetary Systems Now Forming in Orion
Credit: NASA, ESA, M. Robberto (STScI/ESA), the HST Orion Treasury Project Team, & L. Ricci (ESO) Explanation: How do planets form? To help find out, the Hubble Space Telescope was tasked to take a detailed look at one of the more interesting of all astronomical nebulae, the Great Nebula in Orion. The Orion nebula, visible with the unaided eye near the belt in the constellation of Orion, is an immense nearby starbirth region and probably the most famous of all astronomical nebulas. Insets to the above mosaic show numerous proplyds, many of which are stellar nurseries likely harboring planetary systems in formation. Some proplyds glow as close disks surrounding bright stars light up, while other proplyds contain disks further from their host star, contain cooler dust, and hence appear as dark silhouettes against brighter gas. Studying this dust, in particular, is giving insight for how planets are forming. Many proplyd images also show arcs that are shock waves - fronts where fast moving material encounters slow moving gas. The Orion Nebula lies about 1,500 light years distant and is located in the same spiral arm of our Galaxy as our Sun.

说明:行星如何形成?为了找到答案,哈勃太空望远镜对准了一个目标进行了仔细的观察,那就是较为有趣的星云之一:猎户座大星云。在猎户座腰带附近用肉眼就能看到猎户座星云,它是临近的广阔恒星诞生区域,或许也是所有天体星云内最为有名的。在上面这张影像中出现的插图显示的是许多原行星盘,许多恒星孕育场都隐藏着正在成形的行星系统。一些原行星盘也发光,因为其盘面被周围明亮恒星照亮的缘故,而其它原行星盘所拥有的盘面比它们的主宿恒星还大,有些含有较冷的尘埃,因此在明亮的气体背景下显示出黑暗的轮廓。特别的是,研究这些尘埃能让人类了解行星如何形成的线索。许多远行星盘影像还显示了状特征,那是冲击波,由于较快运行的物质遇到了运行较慢的气体而造成。猎户座星云距离我们大约1,500光年远,同我们太阳一样位于银河系相同的旋臂上。

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 楼主| 发表于 2009-12-23 13:03 | 显示全部楼层
本帖最后由 jadiyd 于 2009-12-30 18:19 编辑

2009 December 23

December Sunrise, Cape Sounion
Credit & Copyright: Anthony Ayiomamitis (TWAN)
Explanation: The Sun is a moving target. Its annual motion through planet Earth's sky tracks north and south, from solstice to solstice, as the seasons change. On December 21st, the solstice marking the first day of winter in the northern hemisphere and summer in the south, the Sun rose at its southernmost point along the eastern horizon. Earlier this month, looking toward the Aegean Sea from a well-chosen vantage point at Cape Sounion, Greece, it also rose in this dramatic scene. In the foreground lies the twenty-four hundred year old Temple of Poseidon.

说明:太阳是一个移动的目标每年周而复始的运动,使得太阳在地球的南北天空中移动,从至日到至日,产生了季节变换。在1221,冬至日成为北半球冬季和南半球夏季的第一天,太阳在东方地平线上空的最南端升起。本月初,在希腊苏尼翁海角某处经细选了的有利位置上朝爱琴海看去,太阳在一片生动的画面下升起。位于前景中的是2,400年前建造的海神庙


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发表于 2009-12-23 18:53 | 显示全部楼层
学习,谢谢
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 楼主| 发表于 2009-12-24 13:39 | 显示全部楼层
2009 December 24

Gamma Cas and Friends
Credit & Copyright: Processing - Noel Carboni, Imaging - Greg Parker, New Forest Observatory
Explanation: Gamma Cassiopeiae shines high in northern autumn evening skies. The brightest spiky star in this rich and colorful Milky Way starfield, bluish Gamma Cas marks the central peak in the W-shaped constellation Cassiopeia. A hot, variable, and rapidly rotating star about 600 light-years distant, Gamma Cas also ionizes surrounding interstellar material, including the wispy IC 63 (left) and IC 59 emission and reflection nebulae. The two faint nebulae are physically close to Gamma Cas, separated from the star by only a few light-years. This well-composed, wide-field view of the region spans almost 2 degrees on the sky.

说明仙后座γ闪烁在北方秋季星空中。在这片丰富多彩的银河系星场中,最亮的铆钉状恒星就是泛蓝色仙后座γ星,它出现在这张W型仙后座的中央尖峰处。作为一颗距离我们大约600光年远,炽热而又高速自转的变星仙后座γ电离了周围的星际物质,包括纤细的IC63(左)和IC59发射与反射星云。两个昏暗的星云在物理距离上与仙后座γ很近,仅仅距离数光年远。这张合成效果较好的广域影像里,该区域在天空中覆盖约2度。

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 楼主| 发表于 2009-12-25 20:05 | 显示全部楼层
2009 December 25

A Graceful Arc
Credit & Copyright: Tony Hallas
Explanation: The graceful arc of the Milky Way begins and ends at two mountain peaks in this solemn night sky panorama. Created from a 24 frame mosaic, exposures tracking Earth and sky were made separately, with northern California's Mount Lassen at the left and Mount Shasta at the far right, just below the star and dust clouds of the galactic center. Lassen and Shasta are volcanoes in the Cascade Mountain Range of North America, an arc of the volcanic Pacific Ring of Fire. In the dim, snow-capped peaks, planet Earth seems to echo the subtle glow of the Milky Way's own faint, unresolved starlight.

说明:在这张萧肃的天空全景影像中,银河系优美的弧线首尾起止都位于两座山峰的峰顶处。这张影像由24帧合成,地球和天空的影像拍摄是独立的,左侧是北半球加利福尼亚州拉孙峰,最右侧是沙斯塔峰,就位于银河系中心恒星与尘埃云的下方。拉孙峰和沙斯塔峰是北美洲卡斯克德山脉上的火山,那也是太平洋火山环上的一段。在暗处,白雪覆盖的山尖,地球似乎也反射着银河系发出的昏暗光芒,以及不曾分辨的星光

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 楼主| 发表于 2009-12-26 13:39 | 显示全部楼层
本帖最后由 jadiyd 于 2009-12-30 18:20 编辑

2009 December 26

M51 Hubble Remix
S. Beckwith (STScI), Hubble Heritage Team, (STScI/AURA), ESA, NASA
Additional Processing: Robert Gendler
Explanation: The 51st entry in Charles Messier's famous catalog is perhaps the original spiral nebula - a large galaxy with a well defined spiral structure also cataloged as NGC 5194. Over 60,000 light-years across, M51's spiral arms and dust lanes clearly sweep in front of its companion galaxy (right), NGC 5195. Image data from the Hubble's Advanced Camera for Surveys has been reprocessed to produce this alternative portrait of the well-known interacting galaxy pair. The processing has further sharpened details and enhanced color and contrast in otherwise faint areas, bringing out dust lanes and extended streams that cross the small companion, along with features in the surroundings and core of M51 itself. The pair are about 31 million light-years distant. Not far on the sky from the handle of the Big Dipper, they officially lie within the boundaries of the small constellation Canes Venatici.

说明51位进入查尔斯梅西耶著名星云星团表的天体可能是这个原始的旋涡星云一个具有较好旋涡结构的巨大星系,被编录为NGC5194M51大约覆盖6万光年大小,其旋臂和尘埃带清晰地扫过它的伴星系(右侧)--NGC5195。哈勃的先进巡天相机拍摄到的影像数据经过处理后形成了这张著名交互星系对独一无二的影像。经过处理后进一步锐化了细节,加强了色彩以及对其它昏暗区域的对比,还显示了尘埃带及其延伸流穿过了伴星系,另外M51本身的星核以及周围的特征也出现在影像中。这对星系距离我们大约3,100万光年远。在天空中的距离北斗七星的勺柄不远,位于猎犬座内。


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 楼主| 发表于 2009-12-27 17:28 | 显示全部楼层
本帖最后由 jadiyd 于 2009-12-30 18:19 编辑

2009 December 27

The Cat's Eye Nebula
Credit: J. P. Harrington (U. Maryland) & K. J. Borkowski (NCSU) HST, NASA
Explanation: Three thousand light-years away, a dying star throws off shells of glowing gas. This image from the Hubble Space Telescope reveals the Cat's Eye Nebula to be one of the most complex planetary nebulae known. In fact, the features seen in the Cat's Eye are so complex that astronomers suspect the bright [url=]central object[/url] may actually be a binary star system. The term planetary nebula, used to describe this general class of objects, is misleading. Although these objects may appear round and planet-like in small telescopes, high resolution images reveal them to be stars surrounded by cocoons of gas blown off in the late stages of stellar evolution.

说明:距离我们大约3千光年远,有一颗濒临死亡的恒星正抛射出炽热的气体壳。这张哈勃太空望远镜拍摄的影像,揭示了猫眼星云是迄今为止所知最为复杂行星状星云之一。事实上猫眼星云内的特征如此复杂,天文学家们猜测位于其中央的明亮天体可能是一个双星系统行星状星云这个术语被用来描述这样一类天体,其实是一个误导。尽管在小型望远镜下这些天体看上去圆圆的、类似行星一样,但是在高分辨率影像下能看出,它们中心具有恒星,周围被恒星风吹出的气体包裹成茧状,并且该恒星处于恒星演变的最后阶段。

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 楼主| 发表于 2009-12-28 16:54 | 显示全部楼层
2009 December 28

Barred Spiral Galaxy NGC 6217
Credit: NASA, ESA, and the Hubble SM4 ERO Team
Explanation: Many spiral galaxies have bars across their centers. Even our own Milky Way Galaxy is thought to have a modest central bar. Prominently barred spiral galaxy NGC 6217, pictured above, was captured in spectacular detail in this recently released image taken by the newly repaired Advanced Camera for Surveys on the orbiting Hubble Space Telescope. Visible are dark filamentary dust lanes, young clusters of bright blue stars, red emission nebulas of glowing hydrogen gas, a long bright bar of stars across the center, and a bright active nucleus that likely houses a supermassive black hole. Light takes about 60 million years to reach us from NGC 6217, which spans about 30,000 light years across and can be found toward the constellation of the Little Bear (Ursa Minor).

说明:许多旋涡星系的中心棒都穿过星系的中央。甚至我们银河系也被认为拥有一个合适的中心棒。外表显著的棒旋星系NGC6217就如上面照片中所拍摄到的一样,是哈勃太空望远镜上最近修复的先进巡天相机拍摄,影像中显示了壮观的细节。可以看到影像中有黑暗的丝状尘埃带,明亮蓝色恒星所组成的年轻星团,以及炽热氢气形成的红色发射星云,以及由恒星组成的一条长长的明亮星系棒,穿过了星系的中央,在明亮的活跃星核内可能存在着一个质量超大的黑洞。从NGC6217发出的光需要经过6,000万年才能到达地球,该星系大约覆盖3光年,可以在小熊座内找到它。

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 楼主| 发表于 2009-12-29 19:49 | 显示全部楼层
2009 December 29

Rigel and the Witch Head Nebula
Credit & Copyright: Rogelio Bernal Andreo (Deep Sky Colors)
Explanation: Double, double toil and trouble; Fire burn, and cauldron bubble -- maybe Macbeth should have consulted the Witch Head Nebula. This suggestively shaped reflection nebula on the lower left is associated with the bright star Rigel, to its right, in the constellation Orion. More formally known as IC 2118, the Witch Head Nebula glows primarily by light reflected from Rigel. Fine dust in the nebula reflects the light. Pictured above, the blue color of the Witch Head Nebula and of the dust surrounding Rigel is caused not only by Rigel's blue color but because the dust grains reflect blue light more efficiently than red. The same physical process causes Earth's daytime sky to appear blue, although the scatterers in Earth's atmosphere are molecules of nitrogen and oxygen. Rigel, the Witch Head Nebula, and gas and dust that surrounds them lie about 800 light-years away.

说明:努力吧!忙碌吧!猛烈的柴火烧煮着沸腾的大锅这时候麦克白应该去祈求女巫头星云。影像左下方这个具有形状暗示性的反射星云明亮的参宿七(右侧)一起都位于猎户座内。女巫头星云更多地是被正式称为IC2118,其发出的光主要是反射参宿七的星光。星云内的尘埃起到了反射星光的作用。在上面影像中,蓝色的女巫头星云以及尘埃围绕的参宿七不仅仅是由蓝色的参宿七造成,而是尘埃微粒反射蓝色星光的效应比反射红光强烈的缘故。相同的物理过程还造成了地球白天的天空看上去是蓝色的,尽管地球大气层散射物质是氮气氧气。参宿七,女巫头星云,以及围绕在它们身边的气体与尘埃距离我们大约800光年远。

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 楼主| 发表于 2009-12-30 18:15 | 显示全部楼层
2009 December 30

Spitzer's M101
NASA, JPL-Caltech, K. Gordon (STScI) et al.
Explanation: Big, beautiful spiral galaxy M101 is one of the last entries in Charles Messier's famous catalog, but definitely not one of the least. About 170,000 light-years across, this galaxy is enormous, almost twice the size of our own Milky Way Galaxy. M101 was also one of the original spiral nebulae observed by Lord Rosse's large 19th century telescope, the Leviathan of Parsontown. Recorded at infrared wavelengths by the Spitzer Space telescope, this 21st century view shows starlight in blue hues while the galaxy's dust clouds are in red. Examining the dust features in the outer rim of the galaxy, astronomers have found that organic molecules present throughout the rest of M101 are lacking. The organic molecules tracked by Spitzer's instruments are called polycyclic aromatic hydrocarbons (PAHs). Of course, PAHs are common components of dust in the Milky Way and on planet Earth are found in soot. PAHs are likely destroyed near the outer edges of M101 by energetic radiation in intense star forming regions. Also known as the Pinwheel Galaxy, M101 lies within the boundaries of the northern constellation Ursa Major, about 25 million light-years away.

说明:巨大而又美丽的旋涡星系M101是最后进入查尔斯梅西耶著名星云星团表的天体之一,但也绝不是最不起眼的一个。这个星云异常巨大,覆盖约17万光年,大小是我们银河系的两倍。M101还是原始旋涡星云之一,由罗斯伯爵的19世纪大望远镜(列维亚森)拍到。这张21世纪拍摄的影像是由斯皮策空间望远镜在红外波段下拍摄的,显示了泛蓝色的星光以及红色的星系尘埃云。仔细检查星系外边缘的尘埃特征之后,天文学家们发现,贯穿M101其余区域的有机分子在这里却很少。被斯皮策设备追踪的有机分子被称为多环芳香烃(PAHs)。当然,PAHs银河系内尘埃的普通组成成分,还能在地球上的煤烟中找到。位于M101外层边缘的PAHs似乎是被致密恒星形成区域发出的高能射线侵蚀掉了。M101还被称为风车星系,位于北方的大熊座内,距离我们大约2,500万光年远。

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 楼主| 发表于 2009-12-31 18:17 | 显示全部楼层
本帖最后由 jadiyd 于 2009-12-31 18:19 编辑

2009 December 31
Dust and the Helix Nebula
NASA, JPL-Caltech, Kate Su (Steward Obs, U. Arizona) et al.
Explanation: Dust makes this cosmic eye look red. The eerie Spitzer Space Telescope image shows infrared radiation from the well-studied Helix Nebula (NGC 7293) a mere 700 light-years away in the constellation Aquarius. The two light-year diameter shroud of dust and gas around a central white dwarf has long been considered an excellent example of a planetary nebula, representing the final stages in the evolution of a sun-like star. But the Spitzer data show the nebula's central star itself is immersed in a surprisingly bright infrared glow. Models suggest the glow is produced by a dust debris disk. Even though the nebular material was ejected from the star many thousands of years ago, the close-in dust could be generated by collisions in a reservoir of objects analogous to our own solar system's Kuiper Belt or cometary Oort cloud. Formed in the distant planetary system, the comet-like bodies would have otherwise survived even the dramatic late stages of the star's evolution. 说明:尘埃让这只宇宙之眼看起来是红色的。这张奇异的斯皮策太空望远镜影像显示了螺旋星云(NGC7293)发出的红外射线,星云距离我们大约700光年远,位于宝瓶座内。直径为2光年的尘埃与气体外壳围绕在中央白矮星的周围,它一直以来都被认为是一个极佳的行星状星云实例,这代表了一颗类似太阳一样的恒星进入了演变的最后阶段。但是,斯皮策数据显示,星云的中央恒星本身就陷于极亮的红外光线下。通过模拟显示发光发热是由尘埃碎片盘产生。星云内的物质也是由恒星在数千年前喷出的,距离中心较近的尘埃是由内部物质碰撞产生,这与我们太阳系内的柯伊伯带或者类似彗星状的奥尔特云类似。形成于遥远行星状系统内、类似彗星状的天体甚至可能会在恒星演变的最后阶段存活下来。
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