本帖最后由 人与自然 于 2012-4-3 11:01 编辑
首先解释一下什么叫做“Advent Calendar”
更多内容参阅维基百科：[url=http://en.wikipedia.org/wiki/Advent_calendar]http://en.wikipedia.org/wiki/Advent_calendar[/url]
“Advent Calendar”有点类似中国人进入腊月就开始做过年的准备的这一段时间。西方人过圣诞，也提前一个月。圣诞节前的四个星期是Christmas Advent。advent是降临来临的意思，这个节也称为“降临节”。从倒数第四个周日起，人们就正式进入了兴奋的等待。
Advent Calendar是这一段时间极具代表性的一部分。这是一种可以吃的日历。盒子封面是圣诞老人，共有24个小格子，标了数字，里面有一块巧克力,有的做成圣诞老人，有的做成袜子，有的做成雪撬，有的做的驯鹿，还有蝴蝶节，礼物包，圣诞树等各种不同的形状。小孩子每天打开一格，吃掉一块巧克力，全部吃完了以后，就是圣诞了，大包小包的巧克力糖果接踵而来。
从每年距11月30日最近的一个星期日开始，一直到12月24日圣诞节之前，这大约4周的时间都是“降临节”。这段时间是基督徒们准备和等待基督复活的日子。可能是德国的路德宗教徒最晚于19世纪初首先引入了Advent Calendar的概念，而他们的具体做法，就是发明了Advent Calendar，即“降临节日历”。为此，19世纪初就有人开始想法倒数圣诞节前的日子，比如用粉笔画线，每天挂一小幅跟耶稣有关的图画，或者每天点一根蜡烛等。第一个手工制作的Advent Calendar产生于1851年，20世纪初，开始印刷Advent Calendar，现在，Advent Calendar已经成为圣诞的传统之一。制作和相互寄送贺卡，也成为这一时间的商家赚钱和和人们表达祝福的主要内容。
由于西方圣诞节的类似于中国人过年，居于这样的认识，哈伯望远镜的“Advent Calendar”，其实相当于中国人的“年画”，是著名的“The Big Picture”精选出来的哈伯望远镜照片集合而成，送给全世界的天文爱好者和哈伯迷的圣诞大礼，共25张，极具观赏和科学价值。本贴先贴出2008年度的，2009-2011年度将逐步推出！（原网站图片更大一些，大家可进入愿网站欣赏）
鉴于本人的天文学专业翻译水平不足，对这些熟悉的照片也就不再一一翻译；对一些不太熟悉的照片，有兴趣的坛友可以看看英文解释，基本内容应该是可以清晰理解的。
Hubble Space Telescope Advent Calendar 2008
http://www.boston.com/bigpicture/2008/12/hubble_space_telescope_advent.html
As we head into the traditional western Holiday Season, I'd like to present this Hubble Space Telescope imagery Advent Calendar. Every day, for the next 25 days, a new photo will be revealed here from the amazing Hubble Space Telescope. As I take this chance to share these images of our amazing Universe with you, I wish for a Happy Holiday to all those who will celebrate, and for Peace on Earth to everyone. - Alan (25 photos total - eventually)
麒麟座V838，红巨星的产生的耀发照亮了其以前抛出的气壳
In January 2002, a dull star in an obscure constellation suddenly became 600,000 times more luminous than our Sun, temporarily making it the brightest star in our galaxy. The star, called V838 Monocerotis, has long since faded back to obscurity, but observations of a phenomenon called a "light echo" around the star have uncovered remarkable new features over the following years (this animation covers two years' time). The light echo is light from the earlier explosion echoing off dust surrounding the star. Light from the outburst traveled to the dust and then was reflected to Earth. Because of this indirect path, the light arrived at Earth months after light from the star that traveled directly from the star. (NASA, ESA) More (see this on Google Sky)
引力透镜星系团 Abell 2218，位于天龙座，离我们约20亿光年
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In early January of 2000, Hubble took this image of Galaxy Cluster Abell 2218, and its massive amount of "gravitational lensing". Abell 2218 lies some 2 billion light-years away in the Draco constellation and is so massive that its enormous gravitational field deflects light rays passing through it, much as an optical lens bends light to form an image. These magnifying powers provides a powerful "zoom lens" for viewing distant galaxies that could not normally be observed with the largest telescopes. The visible "arcs" are the distorted images of very distant galaxies, which lie 5 to 10 times farther away than the lensing cluster itself. (NASA, Andrew Fruchter and the ERO Team, STScI) More (see this on Google Sky) #
室女座星系团的成员——NGC 4526中的1a超新星 SN 1994D，哈勃拍摄此图是为了进行宇宙学红移研究。该漩涡星系离我们约5500万光年。
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About 55 million years ago, a star near the dusty lenticular galaxy NGC 4526 exploded into a supernova, seen as a bright spot at lower left. In 1994, the Hubble Space telescope caught the weeks-long explosion as the light from it finally reached the Earth, and we called it Supernova 1994D, a fairly typical stellar explosion. The host galaxy also known as the Lost Galaxy lies in the background and is part of the Virgo Cluster. (NASA, ESA) More (see this on Google Sky) #
著名的碰撞星系 NGC 4038/4039，位于乌鸦座，离我们约5500万光年。
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Also around 55 million light-years distant, we see here the colliding Antennae Galaxies (NGC 4038/NGC 4039) - a pair of interacting galaxies that lie in the constellation Corvus. The two spiral galaxies started to fuse together a few hundred million years ago making the Antenna galaxies the nearest and youngest example of a pair of colliding galaxies. Nearly half of the faint objects in the Antennae are young clusters containing tens of thousands of stars. (NASA, ESA, and the Hubble Heritage Team) More (see this on Google Sky) #
哈勃熏天相机拍摄的猎户座大星云，距离1500光年，可见M43
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This image, taken by the Advanced Camera for Surveys (ACS), represents a small section of a larger mosaic - the sharpest view ever taken of the Orion Nebula - a picture book of star formation with massive young stars that are shaping the nebula and pillars of dense gas that may be the homes of budding stars. The bright glow at left is from M43, a small region being shaped by ultraviolet light from a massive young star. Astronomers call the region a miniature Orion Nebula because only one star is sculpting the landscape. The Orion Nebula has four such stars. The Orion Nebula is 1,500 light-years away, the nearest star-forming region to Earth. (NASA, ESA, M. Robberto - STScI) More (see this on Google Sky) #
这张星系环照片是哈勃太空望远镜拍摄的，照片上显示的是一奇特的星系，它名为“Hoag's Object”，它位于离开地球约6亿光年的巨蛇星座。该星系是由位于黄色核心周围一些炽热浅蓝色恒星组成的正圆环，这星系环的直径约为12万光年，比我们的银河系稍大些。在星系环的外缘浅蓝色调占优势，这是年轻的巨大恒星，而核心主要是更古老的恒星。或许，在“Hoag's Object”核心与外缘之间的暗区拥有某些星团，但是它们非常黯淡，因此看不见它们。
该星系是天文学家Art Hoag在1950年发现的，最初他认为环是一个行星状星云，它是类似我们的太阳的恒星爆炸后的残余，但是他很快放弃了这一假设，并认为这个神秘天体是一星系。1970年对这天体的观察证实了它的星系本质，但是它的许多特性仍是一个谜，例如迄今为止不完全清楚它究竟是如何形成的。
总之，环状星系可以由不同方法形成，其中之一就是两个星系的碰撞。偶尔在碰撞时当一个星系穿过另一个星系时会留下形成新恒星源的“溅斑”。但是在“Hoag's Object”结构中，天文学家没有找到任何碰撞痕迹，有可能，浅蓝色恒星环是从星系旁边飞过的某个星系留下的。天文学家认为，两个星系这样的相遇大约发生在20-30亿年前。
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A nearly perfect ring of hot, blue stars pinwheels about the yellow nucleus of an unusual galaxy known as Hoag's Object. This image captures a face-on view of the galaxy's ring of stars, revealing more detail than any existing photo of this object. The entire galaxy is about 120,000 light-years wide, which is slightly larger than our Milky Way Galaxy. The blue ring, which is dominated by clusters of young, massive stars, contrasts sharply with the yellow nucleus of mostly older stars. What appears to be a gap separating the two stellar populations may actually contain some star clusters that are almost too faint to see. Curiously, an object that bears an uncanny resemblance to Hoag's Object can be seen in the gap at the one o'clock position. The object is probably a background ring galaxy. (NASA/ESA and The Hubble Heritage Team, STScI/AURA) More (see this on Google Sky) #
这个星系多老了？左边的星系是 I Zwicky 18，由它的亮星，推测出它的年龄大约是 5 亿年，因而一度被认为是目前所发现最年轻的星系。这个星系有着复杂的结构，因为它像早期宇宙中的星系一样，正在生成的阶段，但奇怪的是，它离我们非常近 -- 距离大约 5,900 万光年远 -- 而且周围的星系年龄却明显地大很多。由哈伯太空望远镜所拍摄的 I Zwicky 18 的最新影像已帮助我们解开这个谜，在明亮的年轻恒星之中看到混杂着昏暗的年老恒星。因此，现在人们认为 I Zwicky 18 与它的邻居们一样老，年龄大约是 100 亿年，只不过它有新的恒星形成罢了。造成最近这次恒星生成事件的原因，可能是来自于图中右上方 I Zwicky 18 的卫星星系重力改变的影响。
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Called I Zwicky 18, this galaxy - some 59 million light-years distant - has a youthful appearance that resembles galaxies typically found only in the early universe. Hubble has now found faint, older stars within this galaxy, suggesting that the galaxy may have formed at the same time as most other galaxies. I Zwicky 18 is classified as a dwarf irregular galaxy and is much smaller than our Milky Way Galaxy. The concentrated bluish-white knots embedded in the heart of the galaxy are two major starburst regions where stars are forming at a furious rate. The wispy blue filaments surrounding the central starburst regions are bubbles of gas that have been blown away by stellar winds and supernovae explosions from a previous generation of hot, young stars. A companion galaxy lies just above and to the left and may be interacting with I Zwicky 18. (NASA, ESA, and A. Aloisi STScI) More #
在名为猎户座大星云的大型恒星形成区之南，有个编录号为NGC 1999的蓝色反射星云。NGC 1999受到它内部变星猎户座V380星的照亮，它与我们的距离和猎户座大星云相当，大约有一千五百光年远，而且二者都在猎户座分子云团的边缘。在这张跨幅超过十光年的大视野影像里，NGC 1999内有个黝黑横置的T型。在过去，这个暗色天体曾被认为是个尘埃星云，因为遮掩了后方明亮反射星云的光，而以剪影的形式现踪。但最近的红外光观测影像显示，这个T型可能是年轻活跃恒星所造成的一个缺口，是个由活跃年轻恒星喷流和物质流所击穿的空洞。支持这种想法的证据在于，这个区域有许多年轻恒星喷流和物质流所造成的弓形激震亮区；这些激震亮区称为HH天体 (Herbig-Haro objects)，因天文学家George Herbig和Guillermo Haro而得名。在上面影像中，位在NGC 1999下方的亮红色弓形天体是HH1和HH2。这些恒星喷流和物质流，以每秒数百公里的速度冲撞周遭的云气物质。
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Just weeks after NASA astronauts repaired the Hubble Space Telescope in December 1999, the Hubble Heritage Project snapped this picture of NGC 1999, a nebula some 1,500 light-years away from Earth, in the constellation Orion. The Hubble Heritage astronomers, in collaboration with scientists in Texas and Ireland, used Hubble's Wide Field Planetary Camera 2 (WFPC2) to obtain this colour image. (NASA/ESA and the Hubble Heritage Team - STScI) More (see this on Google Sky) #
NGC 6791是我们所知最老和最大的疏散星团之一，但它为什么会含有如此大量的杂质，则仍然是悬案。 典型的疏散星团，通常是由数百颗恒星所组成，而且，恒星的年龄少于十亿年。 NGC 6791很不寻常地含有数千颗恒星，有些恒星的年龄更高达80亿年！更令人不解地是，NGC 6791相当地脏 ； 亦即，它内部金属 (或是说比氦重元素) 的含量，比大多数的星团 都来得高。 以我们的银河系为例，金属含量累积的速率很缓慢。所以，我们预期年老的恒星，金属的含量应该相当低。这些难解的谜团，让上图的NGC 6791，成为天文学家最常研究的疏散星团之一。经由研究NGC 6791这类的星团，天文学家希望能够了解星系核心的恒星如何演化。
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This image of the ancient open star cluster NGC 6791 was taken in early 2008. Studying the dimmest stars in the cluster, astronomers uncovered three different age groups of stars. Two of the populations are burned-out stars called white dwarfs. One group of these low-wattage stellar remnants appears to be 6 billion years old, another appears to be 4 billion years old. The ages are problematically out of sync with those of the cluster's normal stars, which are 8 billion years old. Located 13,300 light-years away in the constellation Lyra, NGC 6791 is one of the oldest and largest open clusters known, containing roughly 10,000 stars. Also interesting to note are the numerous distant galaxies far beyond our Milky Way Galaxy that are visible between the crowded mass of stars. (NASA, ESA, and L. Bedin, STScI) More (see this on Google Sky) #
年轻星团M16包覆在称为是老鹰星云的云气、尘埃和辉光气体里。 这张这个恒星形成区的美丽清晰影像，呈现了因哈伯太空望远镜特写影像而声名大噪的精彩云柱。 这些被称为是大象鼻子或创生之柱的致密尘埃柱，在影像的中心延伸了数光年，而且在重力挤压下不断形成恒星。 来自星团恒星的强烈辐射，浸蚀了云柱顶端的物质，让内部的新生恒星曝露了出来。 从星云左上角伸出的尘埃柱，称为是老鹰星云之仙女，它也是根恒星形成柱。 M16和老鹰星云离我们约有七千光年远，位在长蛇座尾部星云集结的区域，是双筒望远镜或小型望远镜就能轻易看见的天体。
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This object is a billowing tower of cold gas and dust rising from a stellar nursery called the Eagle Nebula. 7,000 light-years distant from us, the soaring tower is 9.5 light-years or about 90 trillion kilometers tall. Stars in the Eagle Nebula are born in clouds of cold hydrogen gas that reside in chaotic neighbourhoods, where energy from young stars sculpts fantasy-like landscapes in the gas. The tower may be a giant incubator for those newborn stars. A torrent of ultraviolet light from a band of massive, hot, young stars [off the top of the image] is eroding the pillar. The column is silhouetted against the background glow of more distant gas. The bumps and fingers of material in the center of the tower are examples of stellar birthing areas. These regions may look small but they are roughly the size of our solar system. The blue colour at the top is from glowing oxygen, the red color in the lower region is from glowing hydrogen. This image was taken in November 2004 with the Advanced Camera for Surveys (NASA, ESA, and The Hubble Heritage Team STScI/AURA) More (see this on Google Sky) #
在大熊座，有一个著名的美丽的旋涡星系，它叫M81，又名波德星系，以正面对着我们。M81是非本星系团的离我们最近的星系。
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This is the sharpest image ever made of the large "grand design" spiral galaxy M81, or Bode's Galaxy made with Hubble data acquired over a two-year period. A spiral-shaped system of stars, dust, and gas clouds, the galaxy's arms wind all the way down into the nucleus. Though the galaxy is located 11.6 million light-years away, the Hubble Space Telescope's view is so sharp that it can resolve individual stars, along with open star clusters, globular star clusters, and even glowing regions of fluorescent gas. Bode's galaxy is about 70,000 light-years across - slightly smaller than our own Milky Way, estimated to be 100,000 light-years in diameter. (NASA, ESA and the Hubble Heritage Team STScI/AURA) More (see this on Google Sky) #
IC 4406是一个位于豺狼座西边的行星状星云，又称为视网膜星云（Retina Nebula），形状类似环面与视网膜，并有拥有黑暗的星尘。证据指出IC 4406可能是个中空的圆柱。
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The "Retina Nebula" is in fact, a dying star named IC 4406. The left and right halves of the Hubble image are nearly mirror images of the other. If we could fly around IC 4406 in a starship, we would see that the gas and dust form a vast donut of material streaming outward from the dying star. From Earth, we are viewing the donut from the side. This side view allows us to see the intricate tendrils of dust that have been compared to the eye's retina. Gas on the inside of the donut is ionized by light from the central star and glows brightly. Light from oxygen atoms is rendered blue in this image; hydrogen is shown as green, and nitrogen as red. One of the most interesting features here is the irregular lattice of dark lanes that criss-cross the center of the nebula. These lanes are about 24 billion kilometers wide, and are like an open mesh veil that has been wrapped around the bright donut. (NASA and The Hubble Heritage Team - STScI/AURA) More (see this on Google Sky) #
它是 本银河系最明亮区域里的一个星云，也是许多宇宙奇事发生的地区。 NGC 3372又叫做 船底座大星云，它是许多大质量恒星和变幻多端云气的家。 船底座海山二星 (Eta Carina)是星云里的最活跃的恒星，它也是1830年代，天空最明亮的恒星之一，不过现在的亮度已经大不如前。 照片中央的锁匙孔星云 (Keyhole Nebula)里，有数个现知最大质量的恒星，而星云的外观也受这些恒星的影响而改变。 船底座大星云 (Carina Nebula)位在船底座，距离我们约7500光年。 上面这张照片是由位在南美洲、智利 (Chile)的Curtis-Schmidt望远镜 (CTIO) 所拍摄。 在接下来的数几千年里，海山二星可能会发生壮观的 超新星爆炸，而甚至在 过去的二年里，它的亮度已经增加一些。
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This image shows a handful of Bok globules (dark clouds of dense dust and gas) within a larger mosaic image of the Carina Nebula assembled in April of 2007. The clumps of dark clouds are nodules of dust and gas that have resisted being completely photoionized by the strong ultraviolet radiation of nearby young, bright stars. The globule at right is nicknamed "the caterpillar" - its glowing edge indicating that it is in the process of photoionization by the hottest stars in the cluster. the Carina nebula lies some 7,500 light-years away from Earth. (NASA, ESA, N. Smith - UC Berkeley, and The Hubble Heritage Team STScI/AURA) More (see this on Google Sky) #
臭蛋星云又名为葫芦星云 (Calabash Nebula)或OH231.8+4.2，在未来的1000年中，它很可能会发展成对称的双瓣形行星状星云。 上面影像中的臭蛋星云，位在南天的船尾座 (Puppis内，距离地球有5000光年远，大小约有1.4光年。
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Resembling a rippling pool illuminated by underwater lights, the Egg Nebula offers astronomers a special look at the normally invisible dust shells swaddling an aging star. These dust layers, extending over one-tenth of a light-year from the star, have an onionskin structure that forms concentric rings around the star. A thicker dust belt, running almost vertically through the image, blocks off light from the central star. Twin beams of light radiate from the hidden star and illuminate the pitch-black dust, like a shining flashlight in a smoky room. The Egg Nebula is located 3,000 light-years away in the constellation Cygnus. This image was taken with Hubble's Advanced Camera for Surveys in September and October 2002. (NASA/ESA and The Hubble Heritage Team STScI/AURA) More (see this on Google Sky) #
土星环
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The gas giant Saturn, seen at full-tilt in November of 1999. Saturn's orbit lies some 1.2 billion kilometers (about 67 light-minutes) away from earth. The planet itself is roughly 9.5 times wider than Earth and its rings - composed of 93 percent water ice - extend out to 120,000 km above its equator, averaging approximately 20 meters in thickness. (NASA and The Hubble Heritage Team STScI/AURA) More #
仙后座A是银河系内中已知的最年轻的超新星遗迹，也是天空中除太阳外最强的射电源。仙后座A，简称Cas A；相关编号：G111.7-2.1、3C 461射电源。在天球的位置为赤经23h23m24s，赤纬+58°48'54"（2000.0历元，约在仙后座κ星以北），离地球约11000光年，视直径5角分，亮度为6等但由于太弥散与银河背景影响，未能以肉眼直接看到。仙后座A质量是太阳的20倍，是一颗密度很高的恒星，距今330年前左右地球可以观测到它的爆发。仙后座A的核心密度相当高，直径为12.5英里（约合20公里），美宇航局钱德拉X射线天文望远镜在1999年首次观测到仙后座A核心爆发形成的超新星。
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The tattered remains of a supernova explosion known as Cassiopeia A (Cas A), the youngest known remnant from a supernova explosion in the Milky Way. This composite image shows the Cas A remnant as a broken ring of bright filamentary and clumpy stellar ejecta. These huge swirls of debris glow with the heat generated by the passage of a shockwave from the supernova blast. The various colours of the gaseous shards indicate differences in chemical composition. Bright green filaments are rich in oxygen, red and purple are sulphur, and blue are composed mostly of hydrogen and nitrogen. Cas A is located ten thousand light-years away from Earth in the constellation of Cassiopeia. (NASA, ESA, and the Hubble Heritage Team STScI/AURA) More (see this on Google Sky) #
“蝗虫星系”，是由两个碰撞星系所组成的一个极漂亮的系统。其拥有一个卷曲的尾巴，里面包含了很多引人注目的恒星群。如今这个星系被认为是两个星系在中途通过合并形成，虽然其母星系的核心还很显然的处于分离状态，但是他们的星盘却相互重叠在一起。一颗超新星于1999年在这个系统内发生爆炸并且天文学家相信强有力的爆炸，使得恒星形成刚刚开始。这个特别的天体位于lynx星座，大约距离地球5亿光年。
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"The Grasshopper", or UGC 4881, is a stunning system consisting of two colliding galaxies. It has a bright curly tail containing a remarkable number of star clusters. The galaxies are thought to be halfway through a merger - the cores of the parent galaxies are still clearly separated, but their discs are overlapping. A supernova exploded in this system in 1999 and astronomers believe that a vigorous burst of star formation may have just started. This notable object is located in the constellation of Lynx, some 500 million light-years away from Earth. UGC 4881 is the 55th galaxy in Arp's Atlas of Peculiar Galaxies. This image is part of a large collection of 59 images of merging galaxies taken by the Hubble Space Telescope and released on the occasion of its 18th anniversary on April 24th, 2008. (NASA, ESA, the Hubble Heritage Team STScI/AURA and A. Evans, University of Virginia, Charlottesville/NRAO/Stony Brook University) More #
著名的创造之柱的一部分，大约7000光年远
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Part of the famous "Pillars of Creation" formation in the Eagle Nebula, this eerie, dark structure, resembling an imaginary sea serpent's head, is a column of cool molecular hydrogen gas (two atoms of hydrogen in each molecule) and dust that is an incubator for new stars. The stars are embedded inside finger-like protrusions extending from the top of the nebula. Each 'fingertip' is somewhat larger than our own solar system. The Eagle Nebula is 7,000 light-years distant from Earth. (Jeff Hester and Paul Scowen - ASU, and NASA/ESA) More (see this on Google Sky) #
NGC2787，离地球2400万光年
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Tightly wound, almost concentric, arms of dark dust encircle the bright nucleus of the otherwise nondescript galaxy, NGC 2787, in this image created by the Hubble Heritage team. Astronomer Marcella Carollo (Swiss Federal Institute of Technology, Zurich) and collaborators used Hubble's Wide Field Planetary Camera 2 to collect the data in January 1999. (NASA/ESA and The Hubble Heritage Team) More (see this on Google Sky) #
这是一颗和太阳类似的恒星，目前已经接近了寿命的终点。发现这颗恒星的是智利塞洛-托罗罗国际观测站的天文学家阿托罗-格麦兹，因此科学家们将这颗距离地球6500光年的恒星命名为“格麦兹的汉堡包”(Gomez's Hamburger)。
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This object, nicknamed Gomez's Hamburger, is a sun-like star about 6,500 light-years away that is nearing the end of its life. The "hamburger buns" are light reflecting off dust and the "patty" is actually the shadow of a thick disk around the central star, which is seen edge-on from Earth. The star itself, with a surface temperature of approximately 18,000 degrees Fahrenheit (10,000 degrees Celsius), is hidden within this disk. However, light from the star does emerge in the directions perpendicular to the disk and illuminates dust above and below it. (NASA and The Hubble Heritage Team - STScI/AURA) More (see this on Google Sky) #
幅度为26000光年的我们银河系的一片星空
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Looking across 26,000 light-years of space toward the center of our Galaxy, Hubble captured this dense view of over 150,000 stars in February of 2004 while monitoring for any dips in brightness, or transits of orbiting planets. 16 candidate stars were found for closer scrutiny. (NASA, ESA, K. Sahu - STScI and the SWEEPS science team) More (see this on Google Sky) #
SN 1006的一部分。SN 1006是公元1006年4月30日到5月1日期间观测到的一颗超新星，位于豺狼座，是历史上人们记录到的视亮度最亮的超新星爆发，在中国、日本、埃及、伊朗，以及欧洲的古籍中均有记录。中国古书《宋史·天文志》中写道，它的光芒可以将地面上的物体照出影子。根据古埃及学者阿尔·本·里端（Ali Ibn Ridwan）的记载，它的亮度远远超过了金星，有可能也超过了上弦月，达到了-9等。据推断，SN 1006很可能属于Ia型超新星爆发，距离地球大约5900光年。 目前对SN 1006的研究主要集中在其遗迹上。SN 1006的遗迹属于壳层型超新星遗迹，观测不到其中央的致密天体。20世纪50年代美国帕洛玛天文台的天文学家沃尔特·巴德试图用48英寸施密特望远镜观测它的遗迹，但未获成功。直到1965年，天文学家使用澳大利亚帕克斯天文台的射电望远镜发现，豺狼座β星附近的射电源PKS 1459-41具有30角分的壳层结构，证认其为超新星SN 1006的遗迹[1]。1976年探测到了遗迹的X射线辐射[2]。1995年，日本的ASCA卫星发现了其遗迹具有X射线同步辐射的亮弧[3]。1998年发现了它能量为TeV量级的高能伽玛射线辐射
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Seen here is a very thin section of a supernova remnant caused by a stellar explosion that occurred more than 1,000 years ago. On or around May 1, 1006 A.D., observers around the world witnessed and recorded the arrival of light from what is now called SN 1006, a tremendous supernova explosion caused by the final death throes of a white dwarf star nearly 7,000 light-years away. The supernova was probably the brightest star ever seen by humans, and surpassed Venus as the brightest object in the night time sky, only to be surpassed by the moon. It was visible even during the day for weeks, and remained visible to the naked eye for at least two and a half years before fading away. Today we know that the shockwave of SN 1006 has a diameter of nearly 60 light-years, and it is still expanding at roughly 6 million miles per hour. (NASA, ESA, and the Hubble Heritage Team - STScI/AURA) More #
著名的猫眼星云。GC6543是一颗行星状星云，位于3000光年远的天龙座，绰号“猫眼星云”，哈勃太空望远镜发现它的结构对称的另人惊讶，这个奇 异的星云是由估计在1000年前，一颗垂死的恒星发生爆发后，抛射出的气体物质构成的。这个遗迹的前身可能是一个双星系统，这个 彩色图片，是由哈勃的广角行星镜头，从三个不同的波段合成的。从黑白图片上可明显的看到物质尘埃被猛烈抛射出来的景象。猫眼星云特别的地方，在于其结构几乎是所有有记录的星云当中最为复杂的一个。从哈勃太空望远镜拍得的图像显示，猫眼星云拥有绳结、喷柱、弧形等各种形状的结构。 现代的研究揭开不少有关猫眼星云的谜团，有人认为星云结构之所以复杂，是来自其连星系统中主星的喷发物质，但至今尚未有证据指其中心恒星拥有伴星。另外，两个有关星云化学物质量度的结果出现重大差异，其原因目前仍不明。
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The Cat's Eye Nebula (NGC 6543), about 3,300 light-years distant, shows a bull's eye pattern of eleven or even more concentric rings, or shells, around the its center. Each "ring" is actually the edge of a spherical bubble seen projected onto the sky - that's why it appears bright along its outer edge. Observations suggest the star ejected its mass in a series of pulses at 1,500-year intervals. These convulsions created dust shells, each of which contain as much mass as all of the planets in our solar system combined (still only one percent of the Sun's mass). The view from Hubble is like seeing an onion cut in half, where each skin layer is discernible. (NASA, ESA, HEIC, and The Hubble Heritage Team - STScI/AURA) More (see this on Google Sky) #
ESO 593-8 ESO 593-8是一对给人深刻印象的相互影响中的星系，一个羽毛状的星系横跨在伴星系上。两星系未来可能会合并成一个单体星系，距离地球6.5亿光年
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ESO 593-8 is an impressive pair of interacting galaxies with a feather-like galaxy crossing a companion galaxy. The two components will probably merge to form a single galaxy in the future. The pair is adorned with a number of bright blue star clusters. ESO 593-8 is located in the constellation of Sagittarius, the Archer, some 650 million light-years away from Earth. (NASA, ESA, the Hubble Heritage -STScI/AURA, ESA/Hubble Collaboration, and A. Evans, University of Virginia, Charlottesville/NRAO/Stony Brook University) More #
著名的哈勃深空场
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This image is called the Hubble Ultra Deep Field, and it is by far my favorite Hubble image. Starting in late 2003, astronomers pointed Hubble at a tiny, relatively empty part of our sky (only a few stars from the Milky Way visible), and created an exposure nearly 12 days long over a four-month period. The result is this amazing image, looking back through time at thousands of galaxies that range from 1 to 13 billion light-years away from Earth. Some 10,000 galaxies were observed in this tiny patch of sky (a tenth the size of the full moon) - each galaxy a home to billions of stars. Go outside tonight, take a ball-point pen with you, and hold it up in front of the night sky at arm's length. The tip of your pen is about 1 millimeter wide, and at arm's length, it would cover the 10,000 galaxies seen in the Ultra Deep Field image. That's how unbelievably massive the visible universe is. By way of comparison, to really put us Earthlings in our place in the Grand Scheme, please have a look at another famous image, the Pale Blue Dot - a photograph taken of the Earth (the tiny pale speck, top center) by Voyager 1 in 1990 from 4 billion miles away (about 6 light-hours). I will finish with the words of astronomer Carl Sagan about this Pale Blue Dot: "That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar", every "supreme leader", every saint and sinner in the history of our species lived there - on a mote of dust suspended in a sunbeam." (NASA/ESA/S. Beckwith - STScI, and The HUDF Team) -- Best wishes to all, and a Happy New Year - Alan. More (see this on Google Sky) #
More links and information
Hubblesite - official site
Hubble Space Telescope - Wikipedia entry
Google Sky - Fun skygazing tool
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