探索宇宙! 每天发布一张有专业天文学家的简短解释和说明的反映我们迷人宇宙的不同影像或照片。
2008 年 06 月 17 日
Eta Carinae and the Homunculus Nebula
船底座η星和侏儒星云
Credit: N. Smith, J. A. Morse (U. Colorado) et al., NASA
影像提供：N. Smith, J. A. Morse (U. Colorado) et al., NASA
Explanation: How did the star Eta Carinae create this unusual nebula? No one knows for sure. About 165 years ago, the southern star Eta Carinae mysteriously became the second brightest star in the night sky. In 20 years, after ejecting more mass than our Sun, Eta Car unexpectedly faded. This outburst appears to have created the Homunculus Nebula, pictured above in a composite image from the Hubble Space Telescope taken last decade. Visible in the above image center is purple-tinted light reflected from the violent star Eta Carinae itself. Surrounding this star are expanding lobes of gas laced with filaments of dark dust. Jets bisect the lobes emanating from the central star. Surrounding these lobes are red-tinted debris captured only by its glow in a narrow band of red light. This debris is expanding most quickly of all, and includes streaming whiskers and bow shocks caused by collisions with previously existing material. Eta Car still undergoes unexpected outbursts, and its high mass and volatility make it a candidate to explode in a spectacular supernova sometime in the next few million years.
说明：船底座η星是如何形成这个奇怪的星云？没人确切地知道。大约165年前，南方的船底座η星神秘地成为夜空中第二明亮的恒星。在之后20年中，船底座η星抛出了比我们太阳质量还大的物质后，突然间变暗了。这次爆发看上去形成了侏儒星云，上面的合成影像是哈勃太空望远镜在上个十年里拍摄的。可以在上面这张影像中央看到紫色光辉，是船底座η星发出来的光经过反射得到。围绕在这颗恒星周围的是正在膨胀中的气体和黑色尘埃。喷流将从中央恒星抛出的气体瓣切成两半。而围绕在气体瓣周围的是只有在红光窄波段下才能看到的红色碎片。这些碎片以极快的速度膨胀，包括先前存在的物质碰撞后形成的须状流和弓形激波。船底座η星仍然经历着意想不到的爆发，并且大质量和高挥发性让它在数百万年之后成为一颗潜在而壮观的超新星。

探索宇宙! 每天发布一张有专业天文学家的简短解释和说明的反映我们迷人宇宙的不同影像或照片。
2008 年 06 月 18 日
Pyramid Ice Crystal Halos Over Finland
芬兰上空锥状冰晶形成的日晕
Credit & Copyright: Kari Nyman
影像提供及版权：Kari Nyman
Explanation: What if the atmosphere above you became one gigantic lens? This actually happens when a nearly transparent sheet of pyramid shaped ice crystals falls from the sky in a common orientation. These ice-crystals act together like millions of miniature ice mirrors, with external and internal reflections from different faces creating arcs and halos of different radii. An amazing display of pyramid ice crystal halos was captured on June 5 above Tampere, Finland. Visible above are very unusual sun halos of 9, 18, 20, 23, and 24 degrees. In contrast, thin and flat falling ice crystals will produce a halo of 22 degrees only. The high clouds containing the ice crystals are faintly visible, as are some sundogs. The usual Sun image was covered behind a light post, and the above image was significantly digitally sharpened. It is not currently known how large areas of nearly uniform pyramidal ice crystals form.
说明：如果你头顶的大气变成了一个巨大的透镜，那会是什么样子？在天空中同一方位上，有透明的锥状冰晶同时落下时，这样的事情就发生了。这些冰晶结合在一起就像是数百万枚微小的镜子一样，通过不同表面的外部反射和内部反射后形成了不同半径的日弧和日晕。6月5日，在芬兰坦佩雷的上空就拍摄到了一轮令人惊讶的锥状冰晶日晕。可以看到上面影像中的非常普通的日晕视角为：9度，18度，20度，23度和24度。相比较，薄而平坦的冰晶只能产生视角为22度的日晕。含有冰晶的高空云微微可见，类似幻日一样。太阳的影像被灯柱覆盖，并且上面影像被处理后，具有严重的锐化现象。现在还不知道均匀的巨大范围的锥状冰晶是如何形成的。

探索宇宙! 每天发布一张有专业天文学家的简短解释和说明的反映我们迷人宇宙的不同影像或照片。
2008 年 06 月 19 日

The Star Streams of NGC 5907
NGC 5907的恒星流
Image Credit & Copyright: R Jay Gabany (Blackbird Observatory) - collaboration; D.Martínez-Delgado(IAC, MPIA), J.Pe?arrubia (U.Victoria) I.Trujillo (IAC) S.Majewski (U.Virginia), M.Pohlen (Cardiff),
影像提供及版权：R Jay Gabany (Blackbird Observatory) - collaboration; D.Martínez-Delgado(IAC, MPIA), J.Pe?arrubia (U.Victoria) I.Trujillo (IAC) S.Majewski (U.Virginia), M.Pohlen (Cardiff),
Explanation: Grand tidal streams of stars seem to surround galaxy NGC 5907. The arcing structures form tenuous loops extending more than 150,000 light-years from the narrow, edge-on spiral, also known as the Splinter or Knife Edge Galaxy. Recorded only in very deep exposures, the streams likely represent the ghostly trail of a dwarf galaxy -- debris left along the orbit of a smaller satellite galaxy that was gradually torn apart and merged with NGC 5907 over four billion years ago. Ultimately this remarkable discovery image, from a small robotic observatory in New Mexico, supports the cosmological scenario in which large spiral galaxies, including our own Milky Way, were formed by the accretion of smaller ones. NGC 5907 lies about 40 million light-years distant in the northern constellation Draco.
说明：巨大的恒星潮汐流围绕着NGC5907星系。这弧状结构形成了纤细的环，从狭窄的侧向直延伸了15万光年远，NGC5907被称为木刺星系或刀锋星系的。记录在这张深空曝光影像中的这道潮汐流，可能是一个矮星系的轨迹，在过去40亿年里，较小的卫星星系被NGC5907撕裂并融合之后，现在只剩下散落在轨道上的碎片了。最终这张显著的影像是新墨西哥州的小口径程控望远镜拍摄，并证实了这样的宇宙假设，就是在包括我们银河系在内的巨大旋涡星系，可以吞噬小星系。NGC5907位于天龙座内，距离我们4,000万光年远。

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2008 June 20

Solstice Moonrise, Cape Sounion
苏尼恩岬，夏至月出
Credit & Copyright: Anthony Ayiomamitis (TWAN)
影像提供及版权：Anthony Ayiomamitis (TWAN)
Explanation: Today's solstice marks the northernmost point of the Sun's annual motion through planet Earth's sky and the astronomical beginning of the northern hemisphere's summer. But only two days ago, the Full Moon nearest the solstice rose close to the ecliptic plane opposite the Sun, near its southernmost point for the year. Astronomer Anthony Ayiomamitis recorded this dramatic picture of the solstice Full Moon rising above Cape Sounion, Greece. The twenty-four hundred year old Temple of Poseidon lies in the foreground, also visible to sailors on the Aegean Sea. In this well-planned single exposure, a telescopic lens makes the Moon loom large, but even without optical aid casual skygazers often find the Full Moon looking astonishingly large when seen near the horizon. That powerful visual effect is known as the Moon Illusion.
说明：今天的夏至标志着太阳周期运动的最北端出现在地球的天空中，并且这一天文事件表明北半球进入了夏天。但仅仅两天前，距离夏至最近的满月，面对太阳在黄道面附近升起，它也位于今年轨道的最南端附近。天文学家Anthony Ayiomamitis拍摄下了这张惊人的影像，夏至满月正从希腊苏尼恩岬上空升起。有2400年之久的海神庙位于影像前景中，爱琴海上的水手也能看到它。在这张设计完美的单张曝光影像中，远视透镜让月球看上去更大，但在没有光学仪器的帮助下，天空观测者肉眼看到位于地平线附近的满月时，还是会觉得变大了很多。那种强大的视觉效应被称为月径幻觉。

翻译：咖啡君
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2008 June 22

Barred Spiral Galaxy NGC 1300
带状螺旋星系NGC1300
Credit: Hubble Heritage Team, ESA, NASA
影像提供：Hubble Heritage Team, ESA, NASA
Explanation: Big, beautiful, barred spiral galaxy NGC 1300 lies some 70 million light-years away on the banks of the constellation Eridanus. This Hubble Space Telescope composite view of the gorgeous island universe is one of the largest Hubble images ever made of a complete galaxy. NGC 1300 spans over 100,000 light-years and the Hubble image reveals striking details of the galaxy's dominant central bar and majestic spiral arms. In fact, on close inspection the nucleus of this classic barred spiral itself shows a remarkable region of spiral structure about 3,000 light-years across. Unlike other spiral galaxies, including our own Milky Way, NGC 1300 is not presently known to have a massive central black hole.
说明：巨大，美丽的带状螺旋星系NGC1300位于大约七千万光年外的波江星座。这张灿烂的岛宇宙的哈勃望远镜的合成图像是哈勃影像所做的完整星系图景中最大的图像。NGC1300大达100,000光年，而哈勃影像发现了这个星系的主要中心棒和宏伟的螺旋臂等引人瞩目的细节。事实上，对这个经典带状螺旋自身的核心的严格检查显示了一个显著的约3,000光年宽的螺旋区域。不像其他螺旋星系，包括我们自己的银河，NGC1300目前并不被认为有一个巨大的中心黑洞。

翻译：咖啡君
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2008 June 23

The International Space Station Expands Again
国际空间站再次扩张
Credit: STS-124 Shuttle Crew, NASA
影像提供：STS-124 Shuttle Crew, NASA
Explanation: The developing International Space Station (ISS) has changed its appearance again. Earlier this month, the Space Shuttle orbiter Discovery visited the ISS and added components that included Japan's Kibo Science Laboratory. The entire array of expansive solar panels is visible in this picture taken by the Discovery Crew after leaving the ISS to return to Earth. The world's foremost space outpost can be seen developing over the past several years by comparing the above image to past images. Also visible above are many different types of modules, a robotic arm, another impressive set of solar panels, and a supply ship. Construction began on the ISS in 1998.
说明：正在发展的国际空间站（ISS）再次改变了它的外貌。这个月的早期，发现号航天飞机轨道飞行器造访了ISS并添加了包括日本的Kibo科学实验室在内的组件。在这张发现号组员离开ISS返回地球时拍摄的照片中可以看到整个豪华的太阳能电板组。通过与之前的照片对比，可以看到全世界最初的空间基地在过去的这些年里的发展。在上面还可以看到许多不同类型的模型，一个机器臂，另一组令人叹为观止的太阳能板，还有供给船。国际空间站始建于1998年。

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2008 年 06 月 24 日
Ithaca Chasma: The Great Rift on Saturn's Tethys
Ithaca Chasma：土卫三上巨大的裂缝
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
影像提供：Cassini Imaging Team, SSI, JPL, ESA, NASA
Explanation: What created the Great Rift on Saturn's moon Tethys? No one is sure. More formally named Ithaca Chasma, the long canyon running across the right of the above image extends about 2,000 kilometers long and spreads as much as 100 kilometers wide. The above image was captured by the Saturn-orbiting robotic Cassini spacecraft as it zoomed by the icy moon last month. Hypotheses for the formation of Ithaca Chasma include cracking of Tethy's outer crust as the moon cooled long ago, and that somehow the rift is related to the huge Great Basin impact crater named Odysseus, visible elsewhere on the unusual moon. Cassini has now been orbiting Saturn for about four years and is scheduled to continue to probe and photograph Saturn for at least two more years.
说明：土卫三上巨大的裂缝由什么造成？没有人能知道。这条正式被称为Ithaca Chasma的狭长峡谷，穿越了上面影像的右侧，一直延伸了2,000公里，足有100公里宽。上面这张影像是由绕土星飞行的卡西尼飞船拍摄，上个月飞船飞越了这颗被冰封了的卫星。关于Ithaca Chasma如何形成的假说包括在很久以前土卫三慢慢变冷的过程中，其外表地壳裂开，以及那条裂缝可能与在别处一个叫奥德修斯的巨大陨石坑有关。卡西尼飞船现在已经绕土星飞行了4年之久，至少在未来的两年多时间里，它还将继续探测并拍摄土星。

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2008 June 25

What is Hanny's Voorwerp?
Hanny's Voorwerp是什么？
Credit: Galaxy Zoo Project, ING
影像提供：Galaxy Zoo Project, ING
Explanation: What is that green thing? A volunteer sky enthusiast surfing through online Galaxy Zoo images has discovered something really strange. The mystery object is unusually green, not of any clear galaxy type, and situated below relatively normal looking spiral galaxy IC 2497. Dutch schoolteacher Hanny van Arkel, discovered the strange green "voorwerp" (Dutch for "object") last year. The Galaxy Zoo project encourages sky enthusiasts to browse through SDSS images and classify galaxy types. Now known popularly as Hanny's Voorwerp, subsequent observations have shown that the mysterious green blob has the same distance as neighboring galaxy IC 2497. Research is ongoing, but one leading hypothesis holds that Hanny's Voorwerp is a small galaxy that acts like a large reflection nebula, showing the reflected light of a bright quasar event that happened in the center of IC 2497 about 100,000 years ago. Pictured above, Hanny's Voorwerp was imaged recently by the 4.2-meter William Hershel Telescope in the Canary Islands by Matt Jarvis, Kevin Schawinski, and William Keel.
说明：绿色的东西是什么？一位志愿天空爱好者通过浏览在线星际动物园影像时，发现了一些很奇怪的东西。这神秘的物质异常的绿，不像任何一种已知的星系类型，其位于外观相对正常的旋涡星系IC2497的下方。荷兰教师Hanny van Arkel去年发现了这个奇怪的绿色“voorwerp”（在荷兰语中，物质的意思）。星际动物园计划鼓励天空爱好者浏览SDSS影像并对星系类型进行分类。现今被广为熟知的Hanny's Voorwerp，在经过后续观测后显示，该神秘的绿斑与邻近的IC2497星系离我们距离相同。研究正在继续，但是主流假说就是Hanny's Voorwerp是一个小星系，看上去就像是一个巨大的反射星云，反射了10万年前在 IC2497星系中央发生的明亮类星体事件发出的光。上面影像中的Hanny's Voorwerp是加那利群岛上的4.2米威廉赫谢尔望远镜在最近拍摄，拍摄者是Matt Jarvis, Kevin Schawinski和William Keel。

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2008 June 26

M27: Not A Comet
M27：不是一颗彗星
Credit & Copyright: Nik Szymanek, w/Faulkes Telescope North
影像提供及版权：Nik Szymanek, w/Faulkes Telescope North
Explanation: Born on June 26th in 1730, astronomer Charles Messier scanned 18th century French skies for comets. To avoid confusion and aid his comet hunting, he diligently recorded this object as number 27 on his list of things which are definitely not comets. In fact, 21st century astronomers would classify it as a Planetary Nebula, but it's not a planet either, even though it may appear round and planet-like in a small telescope. Messier 27 (M27) is now known to be an excellent example of a gaseous emission nebula created as a sun-like star runs out of nuclear fuel in its core. The nebula forms as the star's outer layers are expelled into space, with a visible glow generated by atoms excited by the dying star's intense but invisible ultraviolet light. Known by the popular name of the Dumbbell Nebula, the beautifully symmetric interstellar gas cloud is over 2.5 light-years across and about 1,200 light-years away in the constellation Vulpecula. This impressive color composite highlights subtle jet features in the nebula. It was recorded with a robotic telescope sited in Hawaii using narrow band filters sensitive to emission from oxygen atoms (shown in green) and hydrogen atoms. The hydrogen emission is seen as red (H-alpha) and fainter bluish hues (H-beta).
说明：出生于1730年6月26日的天文学家查尔斯.梅西耶，为了寻找彗星，搜遍了18世纪法国的天空。为了避免混淆并帮助他的彗星搜寻计划，他将这个天体作为第27颗彗星记录在他的彗星名单上，但是实际上这个天体并不是彗星。事实上，21世纪的天文学家将该天体归类为行星状星云，但是它也不是一颗行星，尽管通过小型望远镜看，它的外观可能呈圆形、类行星状。梅西耶27（M27）被认为是一个气体发射星云的极好样板，由中央类似太阳的恒星在消耗完核燃料造成。星云的形成是恒星的外层大气被喷射到太空中，受到濒临死亡恒星发出的不可见紫外光的激发后，原子发出一种可见的光芒。它常被称为哑铃星云，是一个美丽的对称星际气体云，大小超过了2.5光年，位于狐狸座内，距离我们大约1,200光年。这张令人影像深刻的彩色合成影像巧妙地突出了星云的喷射特征。这张影像是位于夏威夷上的一架程控望远镜拍摄的，其利用了窄带滤波片只能让氧原子（显示绿色）和氢原子发出的光通过。可以看到氢原子放射出的红色（H-alpha）以及较为昏暗的泛滥色光（H-beta）。

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2008 June 27


M81: Feeding a Black Hole
M81：喂食黑洞
Credit: X-ray: NASA/CXC/Wisconsin/D.Pooley & CfA/A.Zezas;
Optical: NASA/ESA/CfA/A.Zezas; UV: NASA/JPL-Caltech/CfA/J.Huchra et al.; IR: NASA/JPL-Caltech/CfA
影像提供：X-ray: NASA/CXC/Wisconsin/D.Pooley & CfA/A.Zezas;
Optical: NASA/ESA/CfA/A.Zezas; UV: NASA/JPL-Caltech/CfA/J.Huchra et al.; IR: NASA/JPL-Caltech/CfA
Explanation: This impressive color composite shows spiral galaxy M81 across the electromagnetic spectrum. It combines X-ray data (blue) from the Chandra Observatory, infrared data (pink) from the Spitzer Space Telescope, and an ultraviolet image (purple) from the GALEX satellite, with a visible light (green) Hubble image. The inset highlights X-rays from some of M81's black holes, including black holes in binary star systems with about 10 times the mass of the sun, as well as the central, supermassive black hole of over 70 million solar masses. Comparing computer models of the giant black hole's energy output to the multiwavelength data suggests that feeding that monster is relatively simple -- energy and radiation is generated as material in the central region swirls inwards forming an accretion disk. In fact, the process otherwise appears to be just like the accretion process feeding M81's stellar mass black holes, even though the central black hole is millions of times more massive. M81 itself is about 70,000 light-years across and only 12 million light-years away in the northern constellation Ursa Major.
说明：这张令人影像深刻的彩色合成影像显示了通过了电磁波频普拍摄到的旋涡星系M81。它包含了从钱德拉天文台拍摄的X射线数据（蓝色），斯皮策太空望远镜拍摄的红外数据（粉红色），GALEX卫星拍摄到的紫外影像（紫色）以及哈勃拍摄的可见光影像（绿色）。上面的插图突出了M81内黑洞放射出的X射线，包括位于双星系统内的黑洞，质量大约是太阳的10倍，同时还有位于中央的超级黑洞，其质量是太阳的7,000万多倍。对巨大黑洞能量输出进行计算机模拟比较后得到的多波段数据表明，给这头“怪兽”喂食相对较为简单，当中央区域的物质向内旋入，形成一个吸积盘的同时能量和射线就产生了。事实上，这个过程看上去就像给M81内恒星量级的黑洞吸积过程，尽管中央黑洞质量要大上数百万倍。M81本身大小约7万光年，距离我们仅有1,200万光年远，位于大熊座内。

[ 本帖最后由 咖啡君 于 2008-6-27 21:21 编辑 ]

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2008 June 28

翻译：咖啡君
Fireball at Ayers Rock
艾尔斯山的火球
Credit & Copyright: Joseph Brimacombe
影像提供：Joseph Brimacombe
Explanation: A weekend trip for astrophotography in central Australia can result in gorgeous skyscapes. In this example recorded in March of 2006, the center of our Milky Way Galaxy rises over planet Earth's horizon and the large sandstone formation called Uluru, also known as Ayers Rock. After setting up two cameras to automatically image this celestial scene in a series of exposures, one through a wide-angle and the other through a telephoto lens, photographer Joseph Brimacombe briefly turned his back to set up other equipment. To his surprise, the ground around him suddenly lit up with the brilliant flash of a fireball meteor. To his delight, both cameras captured the bright meteor streak. Highlighted in the telephoto view (inset), the fireball trail shines through cloud banks, just left of Ayers Rock.
说明：在澳大利亚中部的一个天体照相的周末旅行带来了灿烂的天空景色。在这个摄于2006年3月的例子中，银河系的中心从地球地平线上升起，而称为乌鲁卢的巨大的沙岩结构，也被叫做艾尔斯山。将两套照相机设定为一个通过广角，另一个通过长焦，自动拍摄一系列天空景色之后，摄影师Joseph Brimacombe短暂地转身设置其他设备。令他惊奇的是，他周围的土地突然被一个火球流星的耀眼的闪光照亮了。他惊喜的发现两个照相机都拍到了这个闪亮的流星划过天空。在长焦视野中非常突出（插图），火球的踪迹在艾尔斯山左侧闪耀着穿过云带。

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2008 June 29

翻译：咖啡君
Shadow of a Martian Robot
火星机器人的影子
Credit: Mars Exploration Rover Mission, JPL, NASA
影像提供：Mars Exploration Rover Mission, JPL, NASA
Explanation: What if you saw your shadow on Mars and it wasn't human? Then you might be the Opportunity rover currently exploring Mars. Opportunity and sister robot Spirit have been probing the red planet since early 2004, finding evidence of ancient water, and sending breathtaking images across the inner Solar System. Pictured above, Opportunity looks opposite the Sun into Endurance Crater and sees its own shadow. Two wheels are visible on the lower left and right, while the floor and walls of the unusual crater are visible in the background. Opportunity and Spirit have now spent over four years exploring the red world, find new clues into the wet ancient past of our Solar System's second most habitable planet.
说明：如果你在火星看到你的影子，而那不是人类，会怎么样呢？可能你是正在火星探险的机遇号火星车。机遇号和他的姐妹机器人勇气号从2004年起就在这个红色的星球上探测了，找到远古水存在的证据，穿过内太阳系发回令人惊叹的影像。上面的图片，机遇号背对着太阳看进“耐力”火山口时看见自己的影子。可以看见左下角和右下角的两个轮子，而这个不寻常的火山口的地板和墙也能在背景中看到。机遇号和勇气号已经在这个红色的世界探险了4年，找到了太阳系第二可居住星球的远古水分的新的线索

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2008 June 30

In the Center of the Trifid Nebula
三裂星云的中心
Credit & Copyright: Daniel Lopez (Observatorio del Teide)
影像提供及版权：Daniel Lopez (Observatorio del Teide)
Explanation: Clouds of glowing gas mingle with dust lanes in the Trifid Nebula, a star forming region toward the constellation of Sagittarius. In the center, the three prominent dust lanes that give the Trifid its name all come together. Mountains of opaque dust appear on the right, while other dark filaments of dust are visible threaded throughout the nebula. A single massive star visible near the center causes much of the Trifid's glow. The Trifid, also known as M20, is only about 300,000 years old, making it among the youngest emission nebulae known. The nebula lies about 9,000 light years away and the part pictured here spans about 10 light years. This image was created with the 0.8-meter IAC80 telescope on the Canary Islands of Spain.
说明：炽热的气体云混杂着黑暗的尘埃带出现在三裂星云内，该星云是人马座内的一个恒星形成区域。在其中央，三道黑暗的尘埃带述说了三裂星云名称的来历。巨大的不透明尘埃出现在影像右侧，而在整个星云中都能看到灯丝状的尘埃。在中央附近可以看到单独的一颗大质量恒星，这也造就了三裂星云部分光芒。三裂星云也被称为M20，年龄只有30万年，这让它成为迄今为止最年轻的发射星云。该星云距离我们9,000光年远，上面的影像只是星云的一部分，只覆盖了10光年。上面影像是由西班牙加那利群岛上的0.8米的IAC80望远镜拍摄。

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2008 July 1

Pickering's Triangle from Kitt Peak
基特峰上拍摄到的皮克林的三角形
Credit & Copyright: T. Rector (U. Alaska Anchorage), H. Schweiker, WIYN, NOAO, AURA, NSF
影像提供及版权：T. Rector (U. Alaska Anchorage), H. Schweiker, WIYN, NOAO, AURA, NSF
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 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 Pickering's Triangle component pictured above, a component named for a famous astronomer and the wisp's approximate shape. The above image is a mosaic from the 4-meter Mayall telescope at the Kitt Peak National Observatory located in Arizona, USA.
说明：银河系内的一颗恒星如今能看到的只是这样的一团亮丝。大约7,500年前，一颗恒星发生超新星爆炸，并形成了面纱星云，又被称为天鹅圈。在那时，膨胀的星云看起来与新月一样亮，对于生活在有史记载初期阶段的人类来说，星云的光辉数周可见。如今，形成的超新星遗迹已经慢慢退去，只有通过小型望远镜朝天鹅座方向看去才能看到。而仍然存在的面纱星云异常的巨大，尽管它距离我们大约1,400光年远的地方，但在天空中，它覆盖的天区是满月5倍多。在这张完整的面纱星云影像中，细心的读者应该能辨认出上图中皮克林的三角形，这是以一位著名的天文学家再加上它大致的形状而命名。上面的影像是由位于美国亚利桑那州基特峰国家天文台上直径为4米的梅奥尔望远镜拍摄的。

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2008 July 2

Night Shinings
闪耀之夜
Credit & Copyright: Laurent Laveder (PixHeaven.net / TWAN)
影像提供及版权：Laurent Laveder (PixHeaven.net / TWAN)
Explanation: In the early morning hours of June 30th, ghostly clouds hovered in the east in this view of near dawn skies over western France. The noctilucent or night-shining clouds lie near the edge of space, reflecting sunlight from about 80 kilometers above Earth's surface. Usually spotted above the poles in summer, they are now seen with increasing frequency farther from the poles, in this case extending to the photographer's latitude of about 48 degrees north. The trend could be a telltale sign of global changes in the atmosphere. Another 400,000 kilometers away, the Moon's sunlit crescent shines brightly, its night side illuminated by Earthshine. Of course, as a bonus for early risers June's old crescent Moon was followed closely across the sky by the lovely Pleiades star cluster, surrounded by cosmic dust clouds and shining from a mere 400 light-years away.
说明：6月30日凌晨时分，鬼魅的云层出现在临近黎明的东方天空中，这张影像是在法国西部上空拍摄。夜光云位于地球太空的边缘，在地球表面上空80公里的地方反射太阳光。在夏天通常只能在极点上空才出现，但现在它们频繁出现在距离极点较远的地方，在这张影像中夜光云出现在摄影师朝向的北纬48度的地方。这种趋势云也是大气层全球变化的一个信号。而在另一边，距离我们大约40万公里远的月球在太阳的照射下闪闪发亮，其夜晚面被地照光照亮。当然，作为对早起的人的一种奖励，六月的古老新月总是会紧密地伴随着可爱的昴星团划过天空，月亮周围都是宇宙尘埃云，闪烁在距离我们近40万公里的地方。

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2008 July 3

Hoodoo Sky
石林和天空
Credit & Copyright: Wally Pacholka (Astropics.com / TWAN)
影像提供及版权：Wally Pacholka (Astropics.com / TWAN)
Explanation: The strange-looking rock formations in the foreground of this skyscape are called hoodoos. Towers of weathered, eroded sedimentary rock, hoodoos are found in arid regions of planet Earth and are particularly abundant in an area known as Bryce Canyon National Park in southern Utah, USA. The more familiar night sky pictured here was recorded early Monday morning and includes bright star Capella, alpha star of the constellation Auriga, left of center. On the far right, a very over exposed crescent Moon dominates the sky in close conjunction with the sister stars of the Pleiades cluster. The curious shapes of the two tall, illuminated hoodoos suggest their popular monikers; Thor's Hammer (right) and The Temple of Osiris.
说明：在这张天空影像前景中形状奇怪的岩层被称为石林。被风化、侵蚀了的沉积岩形成了塔状结构，在地球的干旱地区能找到这样的石林，特别是在美国犹他州南部布赖斯峡谷国家公园内其数量异常丰富。这里影像中较为熟悉的夜晚天空是在周一凌晨拍摄的，其中包括中央左侧的明亮恒星五车二-御夫座α星。在最右方，一轮过曝了的新月主宰着天空，同时与昴星团姐妹星形成“合”。两座高大且被照亮了的石林形状怪异，被分别称为：托尔的铁锤（右）和奥西里斯神殿。

这里有太多太多漂亮美丽而又令人震撼的照片了，那张：太空站的飓风Ivan 给我的印象很深刻，有一种无尽的可怕的感觉

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2008 July 4


SN 1006 Supernova Remnant
SN 1006超新星遗迹
Image Credit: NASA, ESA, Zolt Levay (STScI)
影像提供：NASA, ESA, Zolt Levay (STScI)
Explanation: A new star, likely the brightest supernova in recorded human history, lit up planet Earth's sky in the year 1006 AD. The expanding debris cloud from the stellar explosion, found in the southerly constellation of Lupus, still puts on a cosmic light show across the electromagnetic spectrum. In fact, this composite view includes X-ray data in blue from the Chandra Observatory, optical data in yellowish hues, and radio image data in red. Now known as the SN 1006 supernova remnant, the debris cloud appears to be about 60 light-years across and is understood to represent the remains of a white dwarf star. Part of a binary star system, the compact white dwarf gradually captured material from its companion star. The buildup in mass finally triggered a thermonuclear explosion that destroyed the dwarf star. Because the distance to the supernova remnant is about 7,000 light-years, that explosion actually happened 7,000 years before the light reached Earth in 1006. Shockwaves in the remnant accelerate particles to extreme energies and are thought to be a source of the mysterious cosmic rays.
说明：在公元1006年，一颗新星照亮了地球的夜空，这可能是人类历史上记录下的最亮超新星。在南方豺狼座方向上能找到恒星爆炸后产生的扩散碎片云，通过电磁波频谱显示，它仍在发出宇宙光。事实上，这张合成影像包含了钱德拉天文台拍摄到的蓝色X射线数据，黄色的光学数据，红色的射电影像数据。现在被称为SN1006的超新星遗迹，其碎片云看上去大约有60光年宽，这就表示其内存在一颗白矮星。作为一个双星系统的一部分，这颗致密的白矮星慢慢地从它的伴星上吸积物质。而其累计的质量最终触发了热核爆炸。因为超新星遗迹距离我们大约7,000光年远，所以在1006年到达地球的光实际上是由7,000年前发生的爆炸发出的。遗迹中的冲击波激发了粒子产生了极高的能量，这被认为是一种神秘宇宙射线源。

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2008 July 5
翻译：咖啡君
Comet Between Fireworks and Lightning
烟火和灯光之间的彗星
Credit & Copyright: Antti Kemppainen
影像提供：Antti Kemppainen
Explanation: Sometimes the sky itself is the best show in town. In January 2007, people from Perth, Australia gathered on a local beach to watch a sky light up with delights near and far. Nearby, fireworks exploded as part of Australia Day celebrations. On the far right, lightning from a thunderstorm flashed in the distance. Near the image center, though, seen through clouds, was the most unusual sight of all: Comet McNaught. The photogenic comet was so bright that it even remained visible though the din of Earthly flashes. Comet McNaught has now returned to the outer Solar System and is now only visible with a large telescope. The above image is actually a three photograph panorama digitally processed to reduce red reflections from the exploding firework.
说明：有时，城市里的天空本身就是最好的舞台。在2007年1月，澳大利亚人聚集在当地海滩愉快地观看远近被照亮的天空。近处，澳大利亚国庆日庆典的烟火绽放。而在右方，远处的天空被雷暴的闪电照亮。然而，在图片中心附近，透过云层看到的是最罕见的景象：彗星McNaught。这颗上相的彗星如此明亮，即使在地球上闪电的干扰下也仍然可见。彗星McNaught现在已经回到了外太阳系，只能在大望远镜上才能看到了。上图实际上是三张照片经数字处理以降低正在爆炸的烟火引起的红色反光的全景图。

[ 本帖最后由 咖啡君 于 2008-7-16 20:53 编辑 ]