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 8
[url=http://antwrp.gsfc.nasa.gov/image/0807/virgo_kerschhuber_big.jpg][img]http://antwrp.gsfc.nasa.gov/image/0807/virgo_kerschhuber.jpg[/img][/url]
[b]In the Heart of the Virgo Cluster [/b]
[b]室女座星系团的中心[/b]
[b]Credit & Copyright: [/b]Günter Kerschhuber (Gahberg Observatory)
[b]影像提供及版权：[/b]Günter Kerschhuber (Gahberg Observatory)
[b]Explanation: [/b]The Virgo Cluster of Galaxies is the closest cluster of galaxies to our Milky Way Galaxy. The Virgo Cluster is so close that it spans more than 5 degrees on the sky - about 10 times the angle made by a full Moon. With its heart lying about 70 million light years distant, the Virgo Cluster is the nearest cluster of galaxies, contains over 2,000 galaxies, and has a noticeable gravitational pull on the galaxies of the Local Group of Galaxies surrounding our Milky Way Galaxy. The cluster contains not only galaxies filled with stars but also gas so hot it glows in X-rays. Motions of galaxies in and around clusters indicate that they contain more dark matter than any visible matter we can see. Pictured above, the heart of the Virgo Cluster includes bright Messier galaxies such as Markarian's Eyes on the upper left, M86 just to the upper right of center, M84 on the far right, as well as spiral galaxy NGC 4388 at the bottom right.
[b]说明：[/b]室女座星系团是距离我们银河系最近的星系团。室女座星系团距离我们如此之近，以至于它在天空中覆盖了5度多的天区――大小约是满月的10倍。而它的中心位于距离我们大约7,000万光年的地方，作为距离我们最近的星系团，室女座星系团内包含超过2,000个星系，而且与我们银河系周围的本地星系团之间产生了显著的引力作用。星系团包含的不仅仅只是富含恒星的星系团，还包括发出x射线的炽热气体。星系团内星系的运动表明那里的暗物质比我们看到的可见物质要多。上面影像拍摄得是室女座星系团的中心，包括明亮的梅西耶星系，比如左上方的马卡林之眼，影像中央右上方的M86，最右边的M84，还有影像右侧底部的旋涡星系NGC4388。
[[i] 本帖最后由 咖啡君 于 2008-7-16 20:56 编辑 [/i]]
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 9
[url=http://antwrp.gsfc.nasa.gov/image/0807/PlanetsMoonFire_zagorodonov.jpg][img]http://antwrp.gsfc.nasa.gov/image/0807/PlanetsMoonFire_zagorodonov_c800.jpg[/img][/url]
[b]Planets and Fire by Moonlight [/b]
[b]月光下的行星和火焰[/b]
[b]Credit & Copyright: [/b]Dmitrii Zagorodnov
[b]影像提供及版权：[/b]Dmitrii Zagorodnov
[b]Explanation: [/b]On July 5th, wandering planets, bright stars, and a young crescent Moon graced western skies after sunset. Arrayed along the solar system's ecliptic plane, the three celestial beacons forming this skyscape's eye-catching line-up with the Moon are Saturn (upper left), then Mars, and finally Regulus, alpha star of the constellation Leo. Of course planet Earth itself lies in the foreground, a scene dominated by the city lights of Santa Barbara, California. The smoky haze hanging over the city is from threatening wild fires still burning along the hill at the right. On Thursday evening, Saturn and Mars can be seen in a much closer pairing or conjunction, separated by only about 3/4 degree on the sky.
[b]说明：[/b]7月5日，迷离的行星，明亮的恒星，以及一轮新月优美地出现在日落后的西方天空中。沿着太阳系的黄道盘面排列，这三个天体形成了这张影像中引人注目的风景，与月球排列在一起的是土星（左上），然后是火星，最后是轩辕十四－狮子座α星。当然地球本身位于影像前景中，这就是加利福尼亚州、圣芭芭拉城市灯光的美景。而影像右侧的黑烟弥漫在城市的上空，这是由仍在燃烧中的森林大火造成。在星期四晚上，能看到土星与火星靠得很紧，形成了合，在天空中相互间距离仅仅3/4度。
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 10
[url=http://antwrp.gsfc.nasa.gov/image/0807/caloris_messenger_falsecolor.jpg][img]http://antwrp.gsfc.nasa.gov/image/0807/caloris_messenger_c800.jpg[/img][/url]
[b]Enhanced Color Caloris [/b]
[b]色彩增强了的[/b][b]Caloris[/b][b]盆地[/b]
[b]Image Credit: [/b]Courtesy of Science/AAAS
[b]影像提供：[/b]Courtesy of Science/AAAS
[b]Explanation: [/b]The sprawling Caloris basin on Mercury is one of the solar system's largest impact basins. Created during the early history of the solar system by the impact of a large asteroid-sized body, the basin spans about 1,500 kilometers and is seen in yellowish hues in this enhanced color mosaic. The image data is from the January 14th flyby of the MESSENGER spacecraft, captured with the MDIS instrument. Orange splotches around the basin's perimeter are now thought to be volcanic vents, new evidence that Mercury's smooth plains are indeed lava flows. Other discoveries at Mercury by NASA's MESSENGER mission include evidence that Mercury, like planet Earth, has a global magnetic field generated by a dynamo process in its large core, and that Mercury's surface has contracted significantly as its core cooled.
[b]说明：[/b]水星上的Caloris盆地是太阳系内最大的撞击盆地之一。在太阳系形成早期，由一颗巨大的小行星状天体碰撞而成，这个盆地大小约1,500公里，在这张色彩增强的影像中显黄色。这张影像数据是由1月14日，信使号飞船飞越水星时利用MDIS设备拍摄的。盆地边缘的桔红色斑点被认为是火山口，新的证据表明，水星的平原实际上是熔岩流区域。NASA的信使号使命还有其他发现，包括水星像地球一样具有全球性磁场，从巨大的核心中由一个类似发电机效应产生，当它的核心冷却下来后，水星表面有明显的收缩。
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 11
[url=http://antwrp.gsfc.nasa.gov/image/0807/MWspitzer_lab_2048.jpg][img]http://antwrp.gsfc.nasa.gov/image/0807/far3kpcarm_adjusted.jpg[/img][/url]
[b]The Far 3kpc Arm [/b]
[b]远三千秒差臂[/b]
[b]Illustration Credit: [/b]R. Hurt (SSC), JPL-Caltech, NASA
[b]图像提供：[/b]R. Hurt (SSC), JPL-Caltech, NASA
[b]Explanation: [/b]A major discovery was lurking in the data. By accident, while preparing a talk on the Galaxy's spiral arms for a meeting of the American Astronomical Society, Tom Dame (Harvard-Smithsonian CfA) found it - a new spiral arm in the Milky Way. The arm is labeled in this illustration as the Far 3kpc Arm, located at a distance of 3 kpc (kiloparsecs) or about 10,000 light-years from the galactic center, on the opposite side from the Sun. Along with the Near 3kpc Arm whose presence was known since the mid 1950s, the counterpart inner arms now establish that the galaxy has a simple symmetry. The arms are defined by shocked interstellar gas flowing along both sides of the Milky Way's central bar. Dame and his collaborator Patrick Thaddeus recorded the presence of both inner spiral arms in their radio data tracking emission from carbon monoxide molecules along the galactic plane. How much star formation goes on in the counterpart arms? Despite this depiction of stars and star forming regions along the arms, the last attempt to search for star formation in the Near 3kpc Arm was in 1980 and didn't turn up any. The discovery of the Far 3kpc Arm has renewed interest in this and other questions about the center of the Milky Way.
[b]说明：[/b]主要的发现都在影像数据里。正为美国天文协会的一次关于星系旋臂的会议上准备一次会谈时，Tom Dame偶然间（哈佛-史密松恩天文物理中心）发现了它--银河系内新出现的一条旋臂。这条旋臂在这张插图里被标为远三千秒差臂，位于距离星系中央大约三千秒差距，或者1万光年远的地方，与我们太阳相对。沿着自20世纪50年代中期就已经了解其存在的近三千秒差臂看去，在其对应位置上的内旋臂已经形成，星系已经是一个较为简单的对称形状。旋臂是由银河系中心棒两边的星际激冷气体形成。Dame和他的搭档Patrick Thaddeus在沿着银河系盘面方向上，利用一氧化碳分子放射出的射电数据跟踪，同时纪录下了两道内部旋臂。在这对内部旋臂上有多少恒星正在形成呢？尽管这里有旋臂上恒星和恒星形成区域的描述，但是最后一次在近三千秒差臂上寻找恒星形成的最后一次尝试是在1980年，但是没有找到任何结果。远三千秒差臂的发现再一次引起人们的兴趣，并且提出了另外的一些关于银河系中心的问题。
[[i] 本帖最后由 咖啡君 于 2008-7-16 21:36 编辑 [/i]]
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 12
[url=http://antwrp.gsfc.nasa.gov/image/0807/NGC7331Web4_goldman.jpg][img]http://antwrp.gsfc.nasa.gov/image/0807/NGC7331Web4_goldman_c800.jpg[/img][/url]
[b][size=4][color=#ff00ff]翻译：咖啡君[/color][/size][/b]
[b]NGC 7331 and Beyond [/b]
[b]NGC 7331及更远处[/b]
[b]Credit & Copyright: [/b]Don Goldman, Sierra Remote Observatories
[b]影像和版权提供：[/b]Don Goldman, Sierra Remote Observatories
[b]Explanation: [/b]Big, beautiful spiral galaxy NGC 7331 is often touted as an analog to our own Milky Way. About 50 million light-years distant in the northern constellation Pegasus, NGC 7331 was recognized early on as a spiral nebula and is actually one of the brighter galaxies not included in Charles Messier's famous 18th century catalog. Since the galaxy's disk is inclined to our line-of-sight, long telescopic exposures often result in an image that evokes a strong sense of depth. The effect is further enhanced in this well-framed view by the galaxies that lie beyond this gorgeous island universe. The background galaxies are about one tenth the apparent size of NGC 7331 and so lie roughly ten times farther away. Their strikingly close alignment on the sky with NGC 7331 occurs just by chance. The visual grouping of galaxies is also known as the Deer Lick Group.
[b]说明：[/b]巨大美丽的螺旋星系NGC 7331经常被认为与我们自己的银河类似。在北部大约5千万光年的距离的飞马座，NGC 7331早些时候被认定为一个螺旋星云，而且是未包括在18世纪的查尔斯梅西耶星团星云列表里面的最亮的星系之一。由于这个星系的圆盘倾向我们的直视线，长的望远镜曝光得到的往往是引起强烈深度感效果的图片。这个效果进一步被存在于这个灿烂的岛宇宙之外的星系的充分限定的视野加强。背景星系是NGC 7331视觉大小的十分之一，大约在十倍远之外。它们偶尔会出现在天空中明显的与NGC7331接近形成队列。这组视觉上的星系也被称为Deer Lick Group。
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 13
[url=http://antwrp.gsfc.nasa.gov/image/0705/deathvalleysky_nps_big.jpg][img=1000,323]http://antwrp.gsfc.nasa.gov/image/0705/deathvalleysky_nps.jpg[/img][/url] [b][size=4][color=#ff00ff][/color][/size][/b]
[b][size=4][color=#ff00ff]翻译：咖啡君[/color][/size][/b]
[b]A Dark Sky Over Death Valley [/b]
[b]死谷上的黑暗天空[/b]
[b]Credit: [/b]Dan Duriscoe, U.S. National Park Service
[b]影像提供：[/b]Dan Duriscoe, U.S. National Park Service
[b]Explanation: [/b]This eerie glow over Death Valley is in danger. Scrolling right will show a spectacular view from one of the darkest places left in the continental USA: Death Valley, California. The above 360-degree full-sky panorama is a composite of 30 images taken two years ago in Racetrack Playa. The image has been digitally processed and increasingly stretched at high altitudes to make it rectangular. In the foreground on the image right is an unusually placed rock that was pushed by high winds onto Racetrack Playa after a slick rain. In the background is a majestic night sky, featuring thousands of stars and many constellations. The arch across the middle is the central band of our Milky Way Galaxy. Light pollution is threatening dark skies like this all across the US and the world, and therefore the International Dark-Sky Association and the US National Parks Service are suggesting methods that can protect them.
[b]说明：[/b]死谷上方奇异的光芒陷入危险了。向右移动能看到美国大陆剩下的最暗的地方的壮观的景象：死谷，加利福尼亚。上方360度整个天空的全景是由两年前在Racetrack Playa拍的30张照片合成的。这张图像经数字处理，渐增地延伸到高纬度使它成为一个矩形。在图像右侧最显眼的位置，是一个在一场雨后被大风毫不费力地推至Racetrack Playa的不寻常的石头。背景是一个宏伟的夜空，展示了数千的星星和许多星座。穿过中部的拱形是银河系的中央光带。这样的光污染威胁着美国和这个世界的夜空，于是国籍黑暗天空协会和美国国家公园管理局在提出能够保护它们的办法。
[[i] 本帖最后由 咖啡君 于 2008-7-16 22:05 编辑 [/i]]
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 14
[url=http://antwrp.gsfc.nasa.gov/image/0807/mars0708_bosman_big.jpg][img]http://antwrp.gsfc.nasa.gov/image/0807/mars0708_bosman.jpg[/img][/url]
[b]Changes in Angular Mars [/b]
[b]火星视角的变化[/b]
[b]Credit & Copyright: [/b]Richard Bosman
[b]影像提供及版权：[/b]Richard Bosman
[b]Explanation: [/b]Does Mars always appear the same? No. As both Earth and Mars orbit the Sun, the apparent angular size of Mars changes as viewed from the Earth. Pictured above from Enschede, Holland, Mars was captured in 2007 and 2008 with 30 separate images, all taken with the same magnification. When Earth and Mars are on opposite sides of the Sun, Mars appears relatively small. Conversely, when Earth and Mars are near each other, Mars looms large and bright. The largest Mars has appeared in recent history was the opposition of August 2003. Since Mars is always more distant from the Sun than the Earth, Mars never shows a crescent phase to Earthlings. Visible also in the above images are the north polar cap of Mars, dark and light soil, clouds, and, in the early images, a global dust storm. The next opposition, when Earth again passes near to Mars, will occur in early 2010.
[b]说明：[/b]火星始终看起来都一样吗？不是。地球和火星都绕太阳旋转，火星外观视角从地球上看在不断变化。上面的影像是在荷兰恩斯赫德拍摄，分别捕捉到了2007年和2008年火星的30张影像，并且都是以同样的放大倍数拍摄。当地球和火星在太阳的不同面时，火星看上去相对较小。相反地，当地球和火星距离较近，火星看上去就显得很大很明亮。在近期，最大时候的火星出现在2003年8月发生冲的时候。因为火星距离太阳始终比地球远，因此火星不会出现盈亏现象。在上面的影像中还可以看到火星的北极冰帽，色彩深浅不一的土壤，云层，以及在早期相片中的出现的全球性沙尘暴。下一次冲将发生在2010年初，到时候地球将再一次近距离距离通过火星。
[[i] 本帖最后由 咖啡君 于 2008-7-16 22:10 编辑 [/i]]
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 15
[url=http://antwrp.gsfc.nasa.gov/image/0807/m8_vanderhaven_big.jpg][img]http://antwrp.gsfc.nasa.gov/image/0807/m8_vanderhaven.jpg[/img][/url]
[b]Gas and Dust of the Lagoon Nebula [/b]
[b]礁湖星云内的气体和尘埃[/b]
[b]Credit & Copyright: [/b]Fred Vanderhaven
[b]影像提供及版权：[/b]Fred Vanderhaven
[b]Explanation: [/b]This beautiful cosmic cloud is a popular stop on telescopic tours of the constellation Sagittarius. Eighteenth century cosmic tourist Charles Messier cataloged the bright nebula as M8, while modern day astronomers recognize the Lagoon Nebula as an active stellar nursery about 5,000 light-years distant, in the direction of the center of our Milky Way Galaxy. Striking details can be traced through this remarkable picture, processed to remove stars and hence better reveal the Lagoon's range of filaments of glowing hydrogen gas, dark dust clouds, and the bright, turbulent hourglass region near the image center. This color composite view was recorded under dark skies near Sydney, Australia. At the Lagoon's estimated distance, the picture spans about 50 light-years.
[b]说明：[/b]当望远镜扫过人马座天空时，这块美丽的宇宙云将会成为一道美丽的风景。18世纪天文学家查尔斯.梅西耶将这个明亮的星云编录为M8，而如今的天文学家将礁湖星云认为是一个活跃的恒星孕育场，距离我们大约5,000光年远，处于我们银河系中心方向上。在这张显著的影像中还可以看到详尽的细节，影像经过处理后去掉了恒星，这样就能更好地显示礁湖星云中炽热氢气发出的灯丝状物质的范围，黑暗的尘埃云，以及影像中央附近明亮而喧闹的沙漏状区域。这张彩色合成影像是在澳大利亚悉尼附近的黑夜下拍摄的。据礁湖星云的估计距离，这张影像大约覆盖50光年。
膜拜。。。。。学习。。。:(:
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 16
[img]http://www.bjp.org.cn/images/2008-07/16/xin_d1be175ead4e4e08b31cb123a1cf1ee1_makemake_nasa.jpg[/img]
[b]Makemake of the Outer Solar System [/b]
[b][font=宋体][size=12pt]外太阳系的[/size][/font][/b][b][size=12pt][font=Times New Roman]Makemake[/font][/size][/b]
[size=12pt][font=Times New Roman]Credit: R. Hurt (SSC-Caltech), JPL-Caltech, NASA
影像提供：R. Hurt (SSC-Caltech), JPL-Caltech, NASA
Explanation: Recently discovered Makemake is one of the largest objects known in the outer Solar System. Pronounced MAH-kay MAH-kay, this Kuiper belt object is only slightly smaller than Pluto, orbits the Sun only slightly further out than Pluto, and appears only slightly dimmer than Pluto. Makemake, however, has an orbit much more tilted to the ecliptic plane of the planets than Pluto. Designated 2005 FY9soon after its discovery by a team led by Mike Brown(Caltech) in 2005, the outer Solar System orb was recently renamed Makemake for the creator of humanity in the Rapa Nui mythology of Easter Island. Additionally, Makemake has been recently classified as a dwarf planetunder the new subcategory plutoid, making Makemake the third cataloged plutoid after Pluto and Eris. Makemake is known to be a world somewhat red in appearance, with spectra indicating it is likely covered with frozen methane. Since no images of Makemake's surface yet exist, an artist's illustration originally meant to depict Sedna has been boldly co-opted above to now illustrate Makemake. A hypothetical moon is visualized above nearly in the direction of our distant Sun.
说明：最近发现的Makemake是迄今未止所知外太阳系最大的天体之一。发音为MAH-kay MAH-kay的这颗柯伊伯带天体只比冥王星略小，其绕太阳的轨道比冥王星轨道略远，而且看上去比冥王星略暗。然而，Makemake轨道面对于黄道的倾斜角度比冥王星还大。Mike Brown (Caltech)带领的小组在2005年发现了它之后，就把它命名为2005FY9，最近这颗外太阳系天体才以复活岛的神话中人类的创造神Makemake名字来重新命名。另外，Makemake最近也被归类为类冥矮行星下的一颗矮行星，这也使得Makemake成为冥王星和闹神星之后第三颗类冥矮行星。Makemake外观偏红色，光谱分析显示它很可能被冰冻的甲烷覆盖。现在还没有关于Makemak的表面影像，上面这张影像是艺术家原本用来描述赛德娜的照片被用来描绘Makemake了。在其附近朝向遥远太阳的方向上还有一颗假想的卫星。
[/font][/size][size=12pt][font=Times New Roman][size=12pt][/size][/font][/size]
[[i] 本帖最后由 qazwsxedcrfv 于 2008-7-21 16:33 编辑 [/i]]
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 17
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/NGC3718_hagerN.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/NGC3718_hager_c800.jpg[/img][/url]
[b]Extra Galaxies [/b]
[font=宋体][size=12pt][b]星系大观[/b][/size][/font]
[font=宋体][size=12pt][b][color=black]Credit & [/color][/b][b][color=black]Copyright[/color][/b][b][color=black]: [/color][/b][color=black]Dietmar Hager[/color][/size][/font]
[font=宋体][size=12pt][font=宋体][size=12pt][color=black]影像提供及版权：Dietmar Hager[/color][/size][/font][/size][/font]
[font=宋体][size=12pt][size=12pt][font=Times New Roman]Explanation: (xxxedit and linkxxx) A careful look at the full field of view for this sharp image reveals a surprising number of galaxies both near and far toward the constellation Ursa Major. The most striking is clearly NGC 3718, the warped spiral galaxy right of center. NGC 3718's faint spiral arms look twisted and extended, its bright central region crossed by obscuring dust lanes. A mere 150 thousand light-years to the left is another large spiral galaxy, NGC 3729. The two are likely interacting gravitationally, accounting for the peculiar appearance of NGC 3718. While this galaxy pair lies about 52 million light-years away, the remarkable Hickson Group 56 can also be seen clustered just below NGC 3718. Hickson Group 56 consists of five interacting galaxies and lies over 400 million light-years away.[/font]
[font=仿宋_GB2312][size=4][size=12pt]说明：仔细观看这张清晰的全景影像，就会发现在大熊座方向上从远及近有大量的星系存在。其中最显著的是清晰的星系NGC3718，这个绕曲的旋涡星系位于影像中央右侧。NGC3718昏暗的旋臂看起来弯曲而且向两边延伸，它明亮的中央区域被模糊的尘埃带贯穿。而距离其左侧15万光年远的地方是另一个旋涡大星系NGC3729。这两个星系间好像存在着相互间的引力作用，因为NGC3718有着奇怪的外观。这对星系距离我们大约5,200万光年远，在影像中还可以看到显著的辛克森56星系群就位于NGC3718的下方。辛克森56星系群包含了5个相互间作用的星系，距离我们超过了4亿光年远。
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[[i] 本帖最后由 qazwsxedcrfv 于 2008-7-22 08:45 编辑 [/i]]
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 18
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/EphesusHadrianus_pan.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/EphesusHadrianus_center.jpg[/img][/url]
[b]Jupiter over Ephesus [/b]
[b][font=宋体][size=12pt]艾菲索斯上空的木星[/size][/font][/b]
[b][size=12pt]Credit & Copyright: Tunç Tezel (TWAN) [/size][/b]
[b][size=12pt]影像提供及版权：Tun? Tezel (TWAN)[/size][/b]
[size=12pt][b]Explanation: A brilliant Jupiter shares the sky with the Full Moon tonight. Since Jupiter is near opposition, literally opposite the Sun in planet Earth's sky, Jupiter will rise near sunset just like the Full Moon. Of course, opposition is also the point of closest approach, with Jupiter shining at its brightest and offering the best views for skygazers. Recorded late last month, this moving skyscape features Jupiter above the southeastern horizon and the marbled streets of the ancient port city of Ephesus, located in modern day Turkey. At the left is a temple dedicated to the Roman emperor Hadrian. The beautiful night sky also includes the arc of the northern summer Milky Way. Lights on the horizon are from the nearby town of Selçuk. Clicking on the image will download the scene as a panorama.[/b][/size]
[size=1][font=仿宋_GB2312][size=12pt]说明：今晚，明亮的木星将与满月一同闪耀在天空中。因为木星正靠近冲，也就是在地球天空中木星的位置与太阳相对，当日落时木星就会升起，就像一轮满月一样。当然，冲是木星与地球最近的点，此时天空中的木星最亮，对于地球上的观测者来是最佳的观测时机。这张影像是上个月末拍摄的，其中拍摄到东南方地平线上空的木星以及古代港口城市艾菲索斯（位于现在的土耳其）大理石铺设的道路。影像左侧的一座寺庙是为了纪念罗马皇帝Hadrian。美丽的夜空还有一段北半球夏季银河。地平线上的光线来自附近城镇塞尔柱。点击上面这张影像可以下载全景影像。[/size]
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[[i] 本帖最后由 qazwsxedcrfv 于 2008-7-22 16:55 编辑 [/i]]
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 July21
[img]http://www.bjp.org.cn/images/2008-07/21/xin_1a8eeea9065144d1a0a0ce3361144073_ngc5426_gemini.jpg[/img]
[size=2][color=black]The Colliding Spiral Galaxies of Arp 271[/color][/size]
[b][size=12pt][font=Helvetica][size=2]Arp 271内碰撞中的旋涡星系[/size][/font][/size][/b]
[b][size=12pt][size=2]Credit & Copyright: Gemini Observatory, GMOS-South, NSF[/size] [/size][/b]
[b][size=12pt][size=2]影像提供及版权：Gemini Observatory, GMOS-South, NSF[/size][/size][/b]
[b][size=12pt][color=navy]Explanation: What will become of these galaxies? Spiral galaxies NGC 5426 and NGC 5427 are passing dangerously close to each other, but each is likely to survive this collision. Most frequently when galaxies collide, a large galaxy eats a much smaller galaxy. In this case, however, the two galaxies are quite similar, each being a sprawling spiral with expansive arms and a compact core. As the galaxies advance over the next tens of millions of years, their component stars are unlikely to collide, although new stars will form in the bunching of gas caused by gravitational tides. Close inspection of the above image taken by the 8-meter Gemini-South Telescope in Chile shows a bridge of material momentarily connecting the two giants. Known collectively as Arp 271, the interacting pair spans about 130,000 light years and lies about 90 million light-years away toward the constellation of Virgo. Quite possibly, our Milky Way Galaxy will undergo a similar collision with the neighboring Andromeda Galaxy in about five billion years. [/color][/size][/b]
[b][size=12pt]说明：这两个星系将会变成什么样？旋涡星系NGC5426和NGC5427以异常危险的距离通过对方，但双方似乎又幸免遇难。当星系发生碰撞时通常发生的是一个较大的星系吞并了较小的星系。在这张影像中，两个星系大小非常相似，都是具有广阔旋臂和致密星系核的旋涡星系。当星系再经历数千万年的演变之后，尽管在潮汐引力造成的气团内会形成新星，但它们的子星不太可能发生碰撞。仔细检查上面的影像，可以发现在两个巨大的星系之间有一条由物质暂时连接的桥梁，这张影像由位于智利，直径为8米的双子南方望远镜拍摄。二者被合称为Arp271，这对相互间作用的星系对覆盖大约13万光年，距离我们大约9,000光年远，位于室女座内。在今后的50亿年里，我们银河系很可能会与邻近的仙女座星系经历一次类似的碰撞。[/size][/b]
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[[i] 本帖最后由 qazwsxedcrfv 于 2008-7-25 09:09 编辑 [/i]]
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 23
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/echuschasma_marsexpress_big.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/echuschasma_marsexpress.jpg[/img][/url]
[color=magenta]High Cliffs Surrounding Echus Chasma on Mars
[/color][color=royalblue]火星Echus裂谷周围陡峭的悬崖[/color]
[color=darkorchid]Credit: G. Neukum (FU Berlin) et al., Mars Express, DLR, ESA[/color]
[size=2][color=darkorange]影像提供：G. Neukum (FU Berlin) et al., Mars Express, DLR, ESA[/color][/size]
[b][color=royalblue]Explanation: What created this great cliff on Mars? Did giant waterfalls once plummet through its grooves? With a four-kilometer drop, this high cliff surrounding Echus Chasma, near an impressive impact crater, was carved by either water or lava. A leading hypothesis is that Echus Chasma, at 100-kilometers long and 10-kilometers wide, was once one of the largest water sources on Mars. If true, water once held in Echus Chasma likely ran over the Martian surface to carve the impressive Kasei Valles, which extends over 3,000 kilometers to the north. Even if initially carved by water, lava appears to have later flowed in the valley, leaving an extraordinarily smooth floor. Echus Chasma lies north of tremendous Valles Marineris, the largest canyon in the Solar System. The above image was taken by the robotic Mars Express spacecraft currently orbiting Mars. [/color][/b]
[b][font=宋体][size=12pt][size=2][color=lime]说明：什么造成了火星上如此陡峭的悬崖？曾经有巨大的瀑布从这里倾泻而下？陡峭的悬崖围绕着Echus深谷，落差有4,000公里，而深谷就位于撞击坑附近，由流水或熔岩侵蚀而成。有一种主要假说认为，这长达100公里，宽为10公里的Echus裂谷曾经是火星上最大的水源之一。如果假设成立，曾经Echus裂谷内的水在火星表面流淌，从而侵蚀出了卡塞峡谷，这条峡谷向北一直延伸了3,000多公里。即使先前被水流侵蚀，但看上去后来熔岩还是流过峡谷，让峡谷底部变得异常地平坦。Echus深谷位于巨大的水手峡谷的北部，水手峡谷是太阳系内最大的峡谷。上面的影像是由火星快车飞船最近绕火星飞行时拍摄的。[/color][/size][/size][/font][/b]
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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 24
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/3spots_hst.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/3spots_hst_c800.jpg[/img][/url]
[size=2][color=orange]When Storms Collide[/color] [/size]
[font=宋体][size=12pt][b][size=2][color=darkolivegreen]当风暴相遇[/color][/size][/b][/size][/font]
[font=宋体][size=12pt][color=magenta]Credit: NASA, ESA, Amy Simon-Miller (Goddard Space Flight Center), N. Chanover (NMSU), G. Orton (JPL)
[/color][color=darkorange]影像提供：NASA, ESA, Amy Simon-Miller (Goddard Space Flight Center),N. Chanover (NMSU), G. Orton (JPL)[/color][/size][/font]
[font=宋体][size=12pt][color=#00ff00][b][size=2][font=Trebuchet MS][color=deepskyblue]Explanation: These detailed Hubble Space Telescope close-ups feature Jupiter's ancient swirling storm system known as the Great Red Spot. They also follow the progress of two newer storm systems that have grown to take on a similar reddish hue: the smaller "Red Spot Jr." (bottom), and smaller still, a "baby red spot". Red Spot Jr. was seen to form in 2006, while the smaller spot was just identified earlier this year. For scale, the Great Red Spot has almost twice the diameter of planet Earth. Moving horizontally from left to right past the Great Red Spot, Red Spot Jr. clearly went below the larger storm, but the smaller spot was pulled in. Emerging on the right, the baby spot's stretched and now paler shape is indicated by the arrow in the frame from July 8. It is expected that the baby red spot will be pulled back and merge, becoming part of the giant storm system.[/color]
[/font][/size][/b][/color][b][size=2][color=lime]说明：这些清晰的哈勃太空特写影像，突出了木星古老的旋涡风暴系统—也被称为大红斑。影像同时还记录下了两个新生风暴系统的演化过程，它们成型之后也有类似的红颜色：较小的“小红斑”（位于底部），还有更小的“幼红斑”。小红斑是在2006年形成的，而幼红斑是在今年年初刚发现。就大小看来，大红斑的直径是地球的两倍。小红斑从左到右在水平方向上运动，在大红斑下通过，而幼红斑被大红斑拉了进去。在7月8日拍摄到的影像中，用箭头所指的就是颜色泛白、形状扭曲了的幼红斑，它位于影像的右侧。科学家们预期幼红斑将再次被大红斑拉回，并最终融合，成为巨大风暴系统的一部分。[/color]
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[[i] 本帖最后由 qazwsxedcrfv 于 2008-7-25 19:43 编辑 [/i]]
[color=magenta]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.
[/color][color=cyan]2008 July 25[/color]
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/m101_spitzer.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/m101_spitzer_c800.jpg[/img][/url]
[color=gray][b]Spitzer's M101 [/b]
[b][font=宋体][size=12pt]斯皮策望远镜下的[/size][/font][/b][b][size=12pt][font=Times New Roman] M101[/font][/size][/b][/color]
[b][size=12pt][font=Times New Roman][color=red]Credit: NASA, JPL-Caltech, K. Gordon (STScI) et al.[/color][/font][/size][/b]
[size=12pt][font=Arial][size=4][color=red][font=宋体][size=12pt][b]影像提供：NASA, JPL-Caltech, K. Gordon (STScI) et al.[/b][/size][/font][/color][/size][/font][/size]
[size=12pt][font=Trebuchet MS][size=2][color=indigo][font=宋体][size=12pt][b]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.[/b][/size][/font][/color][/size][/font][/size]
[size=12pt][font=Times New Roman][font=宋体][size=12pt] [font=黑体][size=4][color=green]说明：美丽而又巨大的旋涡星系M101是最后几个进入查尔斯.梅西耶著名星云星团表的星系之一，但可以确定它不是最小的一个。该星系大小约17万光年，几乎是我们银河系的两倍。M101也是19世纪罗斯爵士的大型望远镜最初发现的旋涡星云之一，该望远镜曾是帕森镇的巨兽。在这张由21世纪斯皮策太空望远镜用红外波段拍摄的影像中，蓝色辉光是恒星光，而红色表示是星系尘埃云。仔细检查星系外围轮廓的尘埃特征后，天文学家发现在M101其它地方出现的有机分子在这里却很少出现。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是银河系尘埃中很普通的组成成分，在地球的烟灰缸中就能找到。很可能是致密恒星形成区域内放射出的高能射线将M101外围边缘附近的PAHs给摧毁了。M101也被称为风车星系，位于北半球大熊座边界，距离我们大约2,500万光年远。[/color][/size][/font][/size][/font][/font][/size]
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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 26
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/IC1805_kbqVersion4.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/IC1805_kbqVersion4_c800.jpg[/img][/url]
[color=magenta]Central IC 1805[/color]
[color=magenta]射电星云IC 1805的中心[/color]
[color=green]Credit & Copyright: Keith Quattrocchi[/color]
[color=green]影像版权提供: Keith Quattrocchi[/color]
[size=3][color=darkorchid][b]Explanation: Cosmic clouds seem to form fantastic shapes in the central regions of emission nebula IC 1805. Of course, the clouds are sculpted by stellar winds and radiation from massive hot stars in the nebula's newborn star cluster (aka Melotte 15). About 1.5 million years young, the cluster stars appear on the right in this colorful skyscape, along with dark dust clouds silhouetted against glowing atomic gas. A composite of narrow and broad band telescopic images, the view spans about 15 light-years and includes emission from hydrogen in green, sulfur in red, and oxygen in blue hues. Wider field images reveal that IC 1805's simpler, overall outline suggests its popular name - The Heart Nebula. IC 1805 is located about 7,500 light years away toward the constellation Cassiopeia. [/b][/color][/size]
[font=Arial][size=3][color=darkolivegreen][b]说明:发射星云IC 434中心区的宇宙云气，拥有各种非常奇特的形状。当然，它们是由星云内的新恒星星团(Melotte 15)之恒星风和辐射所雕塑出的。这群年龄只有一百五十万年的星团，位在这张彩色星野影像的右方，在辉光原子云气的衬托下，它的内部还有许黝黑的尘埃云。这张照片是由望远镜窄波段和宽波段影像组合出来的，视野横跨15光年的区域，并记录了来自氢(绿色)、硫(红色)和氧(蓝色)的辐射。更大视野的IC 1805照片，更可看出为何它被叫做心脏星云。心脏星云位于仙后座内，离我们约有七千五百光年远。[/b][/color][/size][/font]
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 27
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/ic4406_hst_big.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/ic4406_hst.jpg[/img][/url]
[color=purple]IC 4406: A Seemingly Square Nebula [/color]
[color=purple]IC 4406:近乎四方形的星云[/color]
[color=navy]Credit: C. R. O'Dell (Vanderbilt U.) et al., Hubble Heritage Team, NASA
[size=2]影像提供: C. R. O'Dell (Vanderbilt U.) et al., Hubble Heritage Team, NASA[/size][/color]
[b][font=微软雅黑][color=lime][size=3]Explanation: How can a round star make a square nebula? This conundrum comes to light when studying planetary nebulae like IC 4406. Evidence indicates that IC 4406 is likely a hollow cylinder, with its square appearance the result of our vantage point in viewing the cylinder from the side. Were IC 4406 viewed from the top, it would likely look similar to the Ring Nebula. This representative-color picture is a composite made by combining images taken by the Hubble Space Telescope in 2001 and 2002. Hot gas flows out the ends of the cylinder, while filaments of dark dust and molecular gas lace the bounding walls. The star primarily responsible for this interstellar sculpture can be found in the planetary nebula's center. In a few million years, the only thing left visible in IC 4406 will be a fading white dwarf star.[/size] [/color][/font][/b]
[b][color=blue]说明:一颗圆形的恒星怎么会形成一个方形的星云呢?在探索行星状星云IC 4406C 4406时，这样的疑惑不禁显现出来。证据指出IC 4406可能是个中空的圆柱，只是从我们所在的角度看去，看到的是这个圆柱的侧面，所以就看到了方形的模样。若是从IC 4406的上方往下看，看起来就可能跟环状星云差不多。这张代表色照片，是张结合了哈伯太空望远镜在2001年及2002年所拍的影像。热气体自圆柱两端涌出，由黝西尘埃与分子气体组成的黑色细丝则镶嵌在周围壁上。至于造成这座星际雕塑品的始作俑者，我们可以在行星状星云的中心看到此恒星的尊容。再过几百万年，IC 4406将只剩下一颗凋零的白矮星供世人凭吊。[/color][/b]
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 28
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/j1430lens_sdss_big.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/j1430lens_sdss.jpg[/img][/url]
[color=magenta][b][size=3]SDSSJ1430: A Galaxy Einstein Ring[/size][/b]
[b][size=3][font=Times New Roman]SDSSJ1430[/font]：星系的爱因斯坦环[/size][/b][/color]
[b][color=lime]Credit: A. Bolton (UH/IfA) for SLACS and NASA/ESA [/color][/b]
[b][color=lime]影像提供：A. Bolton (UH/IfA) for SLACS and NASA/ESA[/color][/b]
[b][font=Arial][size=3][color=olive][color=green]Explanation: What's large and blue and can wrap itself around an entire galaxy? A gravitational lens mirage. Pictured above on the left, the gravity of a normal white galaxy has gravitationally distorted the light from a much more distant blue galaxy. More normally, such light bending results in two discernable images of the distant galaxy, but here the lens alignment is so precise that the background galaxy is distorted into a nearly complete ring. Since such a lensing effect was generally predicted in some detail by Albert Einstein over 70 years ago, such rings like SDSSJ1430 are now know as Einstein Rings. SDSSJ1430 was discovered during the Sloan Lens Advanced Camera for Surveys (SLACS) campaign, an observation program that inspected lens candidates found by the Sloan Digital Sky Survey (SDSS) with the Hubble Space Telescope's ACS. Strong gravitational lenses like SDSSJ1440 are more than oddities -- their multiple properties allow astronomers to determine the mass and dark matter content of the foreground galaxy lenses. Given these determinations, SLACS data has now been used, for example, to show that dark matter fraction increases with overall galaxy mass. The inset images on the right depict, from top to bottom, a computer reconstructed image of what the background blue galaxy really looks like, just the white foreground galaxy, and just the lensed blue background galaxy.[/color] [/color][/size][/font][/b]
[size=2][font=黑体][i][b][color=sienna][font=宋体][size=12pt]说明：那个蓝色巨大的东西是什么，而且能围绕在整个星系的周围？这是一个引力透镜幻象。上面影像的左侧是一个正常白色星系的重力将更遥远的蓝色星系发出的光引力扭曲后得到的结果。更普遍的情况是，光线的扭曲会让遥远星系形成两张独立的影像，但是在这里透镜排列很精确，以至于背景星系被扭曲后，形成了近似于一个圆环。因为透镜效应是70年前由艾波特.爱因斯坦预言提出，所以SDSSJ1430这样的光环现在被称为爱因斯坦环。SDSSJ1430是在斯隆透镜高级摄像仪观测计划活动期间发现，这是基于斯隆数字巡天和哈伯太空望远镜的ACS相机来寻找透镜候选体的计划。类似SDSSJ1430的强引力透镜有很多古怪的事情，它们的多个特性能让天文学家测定前景星系透镜中物质和暗物质的含量。SLACS的数据现在已经被使用，例如，数据显示随着整个星系质量越大，暗物质比例也就越高。而上面影像右侧的插入图片，从上到下依次是，背景蓝色星系真实看上去的样子，再经过计算机重新处理后的影像、白色的前景星系、以及引力透镜下的蓝色背景星系。[/size][/font]
[/color][/b][/i][/font][/size]
真的是太漂亮了。
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 29
[img]http://www.bjp.org.cn/images/2008-07/29/xin_022659aadfdc4d6c9440c50bf395c297_scenicmilkyway3_hepburn.jpg[/img]
[color=red][b]The Milky Way Over Ontario
安大略湖上空的银河[/b][/color]
[color=blue][b]Credit & Copyright: Kerry-Ann Lecky Hepburn (Weather and Sky Photography)
影像提供及版权：Kerry-Ann Lecky Hepburn (Weather and Sky Photography)[/b][/color]
[b][font=Arial][size=3][color=lime]Explanation: Sometimes, after your eyes adapt to the dark, a spectacular sky appears. Such was the case earlier this month over Ontario, Canada, when part of a spectacular sky also became visible in a reflection off a lake. To start, the brightest objects visible are bright stars and the planet Jupiter, seen as the brightest spot on the upper left. A distant town appears as a diffuse glow over the horizon. More faint still, the disk of the Milky Way Galaxy becomes apparent as a dramatic diffuse band across the sky that seems to crash into the horizon far in the distance. In the foreground, a picturesque landscape includes trees, a lake, and a stone wall. Finally, on this serene night in July when the lake water was unusually clam, reflections appear. Visible in the lake are not only reflections of several bright stars, but part of the Milky Way band itself. Careful inspection of the image will reveal, however, that bright stars leave small trails in the lake reflections that do not appear in the sky above. The reason for this is because the above image is actually a digital composite of time-consecutive exposures from the same camera. In the first set of exposures, sky images were co-added with slight rotations to keep the stars in one place.
[/color][color=darkorchid]说明：当你的眼睛有时候适应了黑夜之后，壮观的天空就会显现。本月早些时候，在加拿大安大略湖上空就出现了这样的事情，同时还有一幕壮观的天空美景倒映在湖面上。在上面影像中可以看到最明亮的天体是那些亮星和木星，木星是影像左上方最亮的点。远方的城镇在地平线上空发出弥漫的光。更远处就是银河系的盘面，样子看上去就像一条生动地模糊带穿过了天空，消失在远处地平线上。影像的前景具有独特的风景，包括树木，湖泊，以及岩壁。最终，当湖面非常平静时，在这张6月夜空影像里，倒影就显现了。在湖面上不仅可以看到数颗明亮的恒星，还能看到银河带。仔细检查这张影像还能看到，明亮的恒星在湖面倒影中留下了细小的轨迹，但在上面的天空中却没有出现。原因是上面的影像实际是一张数字合成影像，由相同相机经过连续曝光而得到。在第一组曝光影像中，影像被叠加并稍微旋转，以保持恒星在相同的位置上。[/color][/size][/font][/b]
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 30
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/isssun_wagner_big.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/isssun_wagner.jpg[/img][/url]
[color=magenta]The International Space Station Transits the Sun
国际空间站凌日
[/color][color=lime]Credit & Copyright: Martin Wagner
影像提供及版权：Martin Wagner[/color]
[b][size=3][font=Arial][color=sienna]Explanation: That's no sunspot. It's the International Space Station (ISS) caught by chance passing in front of the Sun. Sunspots, individually, have a dark central umbra, a lighter surrounding penumbra, and no solar panels. By contrast, the ISS is a complex and multi-spired mechanism, one of the largest and most sophisticated machines ever created by humanity. Also, sunspots occur on the Sun, whereas the ISS orbits the Earth. Transiting the Sun is not very unusual for the ISS, which orbits the Earth about every 90 minutes, but getting one's timing and equipment just right for a great image is rare. Strangely, besides that fake spot, the Sun, last week, lacked any real sunspots. Sunspots have been rare on the Sun since the dawn of the current Solar Minimum, a period of low solar activity. Although fewer sunspots have been recorded during this Solar Minimum than for many previous decades, the low solar activity is not, as yet, very unusual.
[/color][color=darkgreen]说明：那里没有太阳黑子。这是国际空间站（ISS）刚好从太阳前方通过时被拍到的画面。而太阳黑子中央有一个黑色的本影，周围有颜色较浅的半影，并不会出现太阳能电池板。相比较，ISS是较复杂的多重结构，是人类所创造的最大最先进的仪器之一。太阳黑子发生在太阳表面，而ISS只是绕地球运行。凌日对于ISS来说经常发生，因为它每90分钟绕地球一次，但是要想在时间合适而设备完好的情况下拍摄到一张壮观的照片确实很少有的事情。奇怪的是，除了这颗假黑子之外，上周太阳上居然没有任何黑子。自从太阳进入太阳活动极小期后，太阳黑子就很少出现，尽管在这次太阳活动极小期记录下的黑子数量比先前数十年出现的都少，但是太阳活动不频繁也很正常。[/color][/font][/size][/b]
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 31
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/NGC5216_keller.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0807/NGC5216_keller_c800.jpg[/img][/url]
[b][color=sienna]Galaxies on a String
串在一起的星系[/color][/b]
[color=darkorchid][b]Credit & Copyright: Acquisition - Martin Winder, Processing - Warren Keller
影像提供及版权：Acquisition - Martin Winder, Processing - Warren Keller[/b][/color]
[b][size=3][font=Arial][color=seagreen]Explanation: Galaxies NGC 5216 (top right) and NGC 5218 really do look like they are connected by a string. Of course, that string is a cosmic trail of gas, dust, and stars about 22,000 light-years long. Also known as Keenan's system (for its discoverer) and Arp 104, the interacting galaxy pair is some 17 million light-years away in the constellation Ursa Major. The debris trail that joins them, along with NGC 5218's comma-shaped extension and the distorted arms of NGC 5216 are a consequence of mutual gravitational tides that disrupt the galaxies as they repeatedly swing close to one another. Drawn out over billions of years, the encounters will likely result in their merger into a single galaxy of stars. Such spectacular galactic mergers are now understood to be a normal part of the evolution of galaxies, including our own Milky Way.
[/color][/font][color=darkred]说明：星系NGC5216（右上）和NGC5218看上去确实像连成了一串一样。当然，连成串的线是一道由气体，尘埃和恒星组成的宇宙潮汐尾，大约有2.2万光年长。这对有趣的星系对也被称为Keenan系统（以发现者命名）或者Arp104，距离我们大约1,700万光年远，位于大熊座内。连接这两个星系的潮汐尾、NGC 5218的彗星状分肢及NGC 5216的扭曲漩涡臂，都是它们屡次近距离靠近时，在重力相互作用下的产物。再经历数十亿年后，这对遭遇的星系将最终融合成为一个星系。如此壮观的星系融合场面现在也被认为是正常星系演变的一部分，其中也包括我们的银河系。[/color][/size][/b]
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 August 1
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/moongames_lavederN080717_9416.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/moongames_lavederN080717_9416_c800.jpg[/img][/url]
Moon Games
月亮的趣事
Credit & Copyright: Laurent Laveder (PixHeaven.net / TWAN)
影像版权与提供: Laurent Laveder (PixHeaven.net / TWAN)
Explanation: The Moon's measured diameter is around 3,476 kilometers (2,160 miles). But apparent angular size, or the angle covered by an object, can also be important to Moon enthusiasts. Angular size depends on distance, the farther away an object is, the smaller an angle it covers. Since the Moon is 400,000 kilometers away, its angular size is only about 1/2 degree, a span easily covered by the tip of your finger held at arms length, or a measuring tape held in the distance by a friend. Of course the Sun is much larger than the Moon, 400 times larger in fact, but today the New Moon will just cover the Sun. The total solar eclipse can be seen along a track across northern Canada, the Arctic, Siberia, and northern China. (A partial eclipse is visible from a broader region). Solar eclipses illustrate the happy coincidence that while the Sun is 400 times the diameter of the Moon, it is also 400 times farther away giving the Sun and Moon exactly the same angular size.
说明: 根据测量的数据，月亮的直径约为3,476公里，相当于2,160哩。 但是天文爱好者，对于月亮的视张角(apparent angular size)，也就是物体涵盖的角度，是很有兴趣的。 视张角与距离有关，物体越远，涵盖的角度越小。 因为月亮距离地球约400,000公里，涵盖的角度约半度，当你手臂伸直，约为你的手指宽，或是可以请一位朋友在已知的距离，帮你用卷尺量。 太阳比月亮的直径大上400倍，但是对地球而言，月亮的直径与太阳几乎相等。 这次的日全蚀涵盖的区域有北加拿大，极区，西伯利亚以及中国的北边，而半影区涵盖的范围更广。 日全蚀时有件巧合，那就是离太阳的距离约为离月亮的距离400倍，因为太阳的直径恰为月亮的400倍，因此太阳与月亮的 视张角几乎相等。
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 August 2
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/eclipseshirt_haake.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/eclipseshirt_haake800.jpg[/img][/url]
Eclipse Shirt
T恤上的日食影子
Credit & Copyright: Philippe Haake
影像版权与提供: Philippe Haake
Explanation: Of course, everyone is concerned about what to wear to a solar eclipse. No need to worry though, nature often conspires to project images of the eclipse so that stylish and appropriate patterns adorn many visible surfaces - including clothing - at just the right time. Most commonly, small gaps between leaves on trees can act as pinhole cameras and generate multiple recognizable images of the eclipse. In Madrid to view the 2005 October 3rd annular eclipse of the Sun, astronomer Philippe Haake met a friend who had another inspiration. The result, a grid of small holes in a kitchen strainer produced this pattern of images on an 'eclipse shirt'. While Yesterday's solar eclipse was total only along a narrow path beginning in northern Canada, extending across the Arctic, and ending in China, a partial eclipse could be seen from much of Europe and Asia.
说明: 去看日食到底要穿什么衣服，这种困扰每一个人也许都遇过。其实这都是白操心的，因为大自然通常自有想法，迳自以最合宜日食图样来妆点许多表面，如果时间点恰好的话，甚至包括身上穿着的衣物。最常见的例子是树叶之间的间隙，因为它们的作用就像是针孔相机，能在地表上投射出多重的日食影子。2005年10月3日，在西班牙．马德里观测日环食时，天文学家Philippe Haake有位朋友突发奇想，用厨房的捞渣器，制造出T恤上的这些排列整齐的日食影子。虽然昨天的日全食，只有在横跨加拿大北部-北极-中国西部这个窄窄的带状区域才得见，不过日偏食的景像，则在大部份的欧洲和亚洲地区都能看见。
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 August 3
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/ngc290_hst_big.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/ngc290_hst.jpg[/img][/url]
Open Cluster NGC 290: A Stellar Jewel Box
恒星级的珠宝盒 - 疏散星团NGC 290
Credit: ESA & NASA; Acknowledgement: E. Olszewski (U. Arizona)
影像提供: ESA & NASA; 志谢: E. Olszewski (U. Arizona)
Explanation: Jewels don't shine this bright -- only stars do. Like gems in a jewel box, though, the stars of open cluster NGC 290 glitter in a beautiful display of brightness and color. The photogenic cluster, pictured above, was captured recently by the orbiting Hubble Space Telescope. Open clusters of stars are younger, contain few stars, and contain a much higher fraction of blue stars than do globular clusters of stars. NGC 290 lies about 200,000 light-years distant in a neighboring galaxy called the Small Cloud of Magellan (SMC). The open cluster contains hundreds of stars and spans about 65 light years across. NGC 290 and other open clusters are good laboratories for studying how stars of different masses evolve, since all the open cluster's stars were born at about the same time.
说明: 珠宝没这么明亮，只有恒星会如斯。但类似珠宝盒里的珍宝，疏散星团NGC 290内的恒星，美丽地闪烁着各种不同的光芒和颜色。上面这个很上镜头星团的影像，是不久之前由哈伯太空望远镜所拍摄的。和球状星团比起来，疏散星团内的恒星通常较年轻，数量较少，拥有较高比率的蓝色恒星。NGC 290位在邻近的小麦哲伦星系内，离我们约有二十万光年远。这个疏散星团有数百颗成员星，跨度大约为65光年。NGC 290及其他疏散星团，是研究不同质量的恒星如何演化的好实验室，因为疏散星团的成员大约都是在同一时间诞生的。
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 August 4
[img]http://www.bjp.org.cn/images/2008-08/04/xin_c69615e4553a48c2a52895b1e8b66954_catseye_chandra.jpg[/img]
X-Rays from the Cat's Eye Nebula
X射线下拍摄到的猫眼星系
Credit: X-ray: NASA/CXC/SAO; Optical: NASA/STScI
影像提供：Ｘ-射线NASA/CXC/SAO; 光学: NASA/STScI
Explanation: Haunting patterns within planetary nebula NGC 6543 readily suggest its popular moniker -- the Cat's Eye nebula. Starting in 1995, stunning false-color optical images from the Hubble Space Telescope detailed the swirls of this glowing nebula, known to be the gaseous shroud expelled from a dying sun-like star about 3,000 light-years from Earth. This composite picture combines the latest Hubble optical image of the Cat's Eye with new x-ray data from the orbiting Chandra Observatory and reveals surprisingly intense x-ray emission indicating the presence of extremely hot gas. X-ray emission is shown as blue-purple hues superimposed on the nebula's center. The nebula's central star itself is clearly immersed in the multimillion degree, x-ray emitting gas. Other pockets of x-ray hot gas seem to be bordered by cooler gas emitting strongly at optical wavelengths, a clear indication that expanding hot gas is sculpting the visible Cat's Eye filaments and structures. Gazing into the Cat's Eye, astronomers see the fate of our sun, destined to enter its own planetary nebula phase of evolution ... in about 5 billion years.
说明：行星状星云NGC6543内绚丽的图案已经说明了它那广为人知的名字：猫眼星云。从1995年，哈勃太空望远镜就开始拍摄绚丽的假色光学影像，详细地揭示了这个炽热星云内的旋涡状结构，该星云被认为是一颗类似太阳的垂死恒星吹出了外层气体罩之后形成，它距离我们地球3,000光年远。这张合成影像合成了猫眼星云最新的哈勃光学影像以及钱德拉天文台拍摄的最新X-射线数据，揭示了其内令人吃惊的致密X-放射线，这就表明星云内存在着极度炽热的气体。X-放射线以蓝色调，层次不一地出现在星云的中央。很明显，星云的中央星处于数百万度的高温中，Ｘ射线放射出气体。而另一部分Ｘ-射线放射出的炽热气体遇上了在光学波段下的强烈较冷气体，很明显可以看到，扩张的气体正雕蚀着可见猫眼星云内的灯丝状物质和结构。凝视着猫眼星云，天文学家们看到了我们太阳的命运，在大约50亿年之后最终将进入行星状星云阶段。
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 August 5
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/eclipsechina_buckingham_big.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/eclipsechina_buckingham.jpg[/img][/url]
A Total Solar Eclipse Over China
中国上空的日全食
Credit & Copyright: Bill Buckingham
影像提供及版权：Bill Buckingham
Explanation: What's that black dot over the Sun? The Moon. This past weekend, the Sun went dark during the day as the Moon completely covered it. The total solar eclipse was visible over a thin swath of Earth extending from northern Canada to China. As shown above, many sky enthusiasts gathered to witness the total or partial solar eclipse, which lasted only a few minutes. The above image was taken during totality near Barkol in Xinjiang, China, with the Barkol Shan mountain range visible on the horizon. Although the brightest parts of the Sun are covered, the normally invisible corona of hot gas surrounding the Sun became prominent. Just to the upper left of the Moon darkened Sun are planets Mercury and Venus. The increased darkening of the sky toward the right indicates the darkened atmosphere created by the passing shadow cone of the total solar eclipse. The next total solar eclipse will occur next July and be visible in parts of India and China.
说明：太阳上的黑点是什么？那是月球。在过去的周末，当月球完全遮挡住太阳的时候，太阳变暗了。从加拿大北部延伸到中国的一条狭长地带上才能看到日全食。上面显示的图片中，许多天文爱好者聚集到一起，来观看日全食或者日偏食的发生，而那只持续了几分钟。上面的影像是在中国新疆巴里坤附近，发生日全食期间拍摄，在影像中可以看到地平线上方是巴里坤山脉。尽管太阳最明亮的部分被遮挡了，但是平常不可见的、由炽热气体形成的日冕却变得异常突出。就在月球遮挡住太阳的左上方就是水星和金星。右侧的天空逐渐变暗这就表明日全食的影锥通过了地球的大气层 ，使得那里变暗。下一次日全食将发生在明年7月，印度和中国的部分地区可见。
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 August 6
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/ngc1818_hst_big.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/ngc1818_hst.jpg[/img][/url]
NGC 1818: A Young Globular Cluster
NGC1818：年轻的球状星团
Credit: Diedre Hunter (Lowell Obs.) et al., HST, NASA
影像提供：Diedre Hunter (Lowell Obs.) et al., HST, NASA
Explanation: Globular clusters once ruled the Milky Way. Back in the old days, back when our Galaxy first formed, perhaps thousands of globular clusters roamed our Galaxy. Today, there are perhaps 200 left. Many globular clusters were destroyed over the eons by repeated fateful encounters with each other or the Galactic center. Surviving relics are older than any Earth fossil, older than any other structures in our Galaxy, and limit the universe itself in raw age. There are few, if any, young globular clusters in our Milky Way Galaxy because conditions are not ripe for more to form. Things are different next door, however, in the neighboring LMC galaxy. Pictured above is a "young" globular cluster residing there: NGC 1818. Observations show it formed only about 40 million years ago - just yesterday compared to the 12 billion year ages of globular clusters in our own Milky Way
说明：球状星团曾经统治着银河系。回到从前，当我们银河系刚刚形成的时候，很可能有成千上万个球状星团漫游在我们银河系内。而到今天，它们才保留下来200个。经过数十亿年的时间之后，很多球状星团在相互间或者星系中心的致命碰撞下而毁灭。留下来的遗迹比地球上发现的化石还久远，比我们星系内任何其他结构都年老，并且将宇宙本身限定在一个最初的年龄段上。在我们银河系内很少出现年轻的球状星团，因为对于形成较多球状星团的环境并不具备。但在临近的大麦哲伦星系内，情况就不一样。上面影像中的年轻星系团被称为NGC1818。经过观测证实它形成于4,000万年前，相对于我们银河系内，年龄在120亿年之久的球状星团来说，它就像在昨天诞生一样。
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[[i] 本帖最后由 wqmao00 于 2008-8-12 09:45 编辑 [/i]]
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 August 7
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/TSE2008_beldea.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/TSE2008_beldea_c800.jpg[/img][/url]
At the Sun's Edge
日盘的边缘
Credit & Copyright: Catalin Beldea (Descopera Magazine)
影像版权与提供: Catalin Beldea (Descopera Magazine)
Explanation: A train trip on the Trans-Siberian railway to Novosibirsk resulted in this stunning view along the edge of the Sun recorded during the August 1st total solar eclipse. The picture is a composite of two images taken at special moments in the eclipse sequence, corresponding to the very beginning and the very end of the total eclipse phase. Those times are known to eclipse chasers as 2nd and 3rd contact. Bright beads around the Moon's dark silhouette are rays of sunlight shining through lunar valleys at the edge of the lunar disk. But the composite view also captures solar prominences, looping structures of hot plasma suspended in magnetic fields, extending beyond the Sun's edge.
说明: 车舟劳顿地搭乘西伯利亚横贯铁路的长程列车到新西伯利亚，为了的就是上面这种出现在8月1日的日全食动人景象。这幅影像是由拍摄于日全食阶段起点和终点的两张照片组合出来的。对日月食爱好者来说，这些时间点分别对应于食既 (2nd contact)和生光 (3rd contact)。影像中，月球黝黑暗影边缘所镶的明亮光珠，其实是穿过月盘边缘低谷的阳光。这张组合影像同时也记录了日珥，它们是在日盘边缘沿着环状磁场泛流而出的炽热电浆。
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 August 8
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/TSE2008_luethen.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/TSE2008_luethen800.jpg[/img][/url]
The Crown of the Sun
日冕
Credit & Copyright: Hartwig Luethen
影像版权与提供: : Hartwig Luethen
Explanation: During a total solar eclipse, the Sun's extensive outer atmosphere, or corona, is an inspirational sight. The subtle shades and shimmering features of the corona that engage the eye span a brightness range of over 10,000 to 1, making them notoriously difficult to capture in a single picture. But this composite of 28 digital images ranging in exposure time from 1/1000 to 2 seconds comes close to revealing the crown of the Sun in all its glory. The telescopic views were recorded near Kochenevo, Russia during the August 1 total solar eclipse and also show solar prominences extending just beyond the edge of the eclipsed sun. Remarkably, features on the dark near side of the New Moon can also be made out, illuminated by sunlight reflected from a Full Earth.
说明: 在日全蚀的时候，我们可以观察 太阳的大气层形状，或称为日冕，日冕是一种太阳的光辉。 日冕层 的外形以及不断地闪烁着光度，光度变化的对比可以高达10,000倍，因此很难用一张图就呈现它的风貌。 这是由28张数位影像所叠合的一张图片，其中曝光的时间从1/1000到2秒，因此可以表现出有皇冠般 太阳的万丈光芒。 这是在俄罗斯的科克涅夫(Kochenevo, Russia)利用 望远镜 所拍摄的镜头，时间是八月一日的日全蚀时刻，从这张照片也可以观测到太阳日珥(prominences)，就在被遮蔽太阳的 边缘， 很有趣的是，月亮的背对太阳的一面也受到地球的反射光照亮，而呈现在这张照片中。
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 August 9
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/PerseidMoonlightAurora9_westlake_big.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/PerseidMoonlightAurora9_westlake.jpg[/img][/url]
Aurora Persei
极光与英仙座流星
Credit & Copyright: Jimmy Westlake (Colorado Mountain College)
影像版权与提供: Jimmy Westlake (Colorado Mountain College)
Explanation: Dark skies are favored for viewing meteor showers -- so the best viewing of this year's Perseids will occur in the early morning. While the Perseid meteor shower is scheduled to peak over the next few days, bright light from a gibbous Moon will also flood the early evening and mask the majority of relatively faint meteors. Still, skygazing in the early morning after the Moon sets (after about 2 AM local time) could reveal spectacular earthgrazing meteors. Persisting observing at any time after sunset can reward northern hemisphere watchers looking for occasional Perseid fireballs. Astronomer Jimmy Westlake imaged this bright Perseid meteor despite the combination of moonlight and auroral glow over Colorado skies in August of 2000.
说明: 黝黑的天空有利于观赏流星雨，因此的看今年英仙座流的最佳时机是在清晨时分。英仙座流星雨的极大期将出现在接下来的这数天里，虽然渐盈月的明亮月光会照耀着清晨的夜空，让较占大多数的暗流星隐而不显，但是在清晨二点月落之后，观星人就有机会看到掠过长空的亮流星，而够坚持的北半球观星人，在日落之后，都有机会看见间歇出现英仙座火流星。在2000年的8月，天文学家immy Westlake拍下了这幅在极光和月光中的明亮英仙座流星。
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 August 10
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/AS11JK44-6633-34.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/AS11JK44-6633-34_c800.jpg[/img][/url]
The Eagle Rises
老鹰号返回舱
Credit: Apollo 11, NASA - Stereo Image Copyright: John Kaufmann (ALSJ)
影像提供: Apollo 11, NASA - Stereo Image Copyright: John Kaufmann (ALSJ) 影像提供: Apollo 11, NASA - Stereo Image Copyright: John Kaufmann (ALSJ)
Explanation: Get out your red/blue glasses and check out this remarkable stereo view from lunar orbit. Created from two photographs (AS11-44-6633, AS11-44-6634) taken by astronaut Michael Collins during the 1969 Apollo 11 mission, the 3D anaglyph features the lunar module ascent stage, dubbed The Eagle, as it rises to meet the command module in lunar orbit. Aboard the ascent stage are Neil Armstrong and Buzz Aldrin, the first to walk on the Moon. The smooth, dark area on the lunar surface is Mare Smythii located just below the equator on the extreme eastern edge of the Moon's near side. Poised beyond the lunar horizon, is our fair planet Earth.
说明: 取出你的红/蓝眼镜来观赏这张从月球轨道取得的精彩立体影像。 影像是由宇航员Michael Collins在1969年阿波罗11号探月任务时所拍摄的两张照片 (AS11-44-6633, AS11-44-6634)所组合出来的，并呈现了名为老鹰号的登月艇回收舱升空和指挥舱会合的立体景象。返回舱当时搭载着阿姆斯壮和艾德宁这两位首先在月面行走的人类。在月球近端东方地平线附近的黝黑平滑区域称为Smythii高原，而在它后方地平面附近的是我们美丽的地球。
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 August 11
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/cygnusx1_stsci_big.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/cygnusx1_stsci.jpg[/img][/url]
Black Hole Candidate Cygnus X-1
恒星黑洞候选天鹅座X-1
Credit: ESA, Hubble
图示提供: ESA, Hubble
Explanation: Is that a black hole? Quite possibly. The Cygnus X-1 binary star system contains one of the best candidates for a black hole. The system was discovered because it is one of the brightest X-ray sources on the sky, shining so bright it was detected by the earliest rockets carrying cameras capable of seeing the previously unknown X-ray sky. The star's very name indicates that it is the single brightest X-ray source in the constellation of the Swan Cygnus. Data indicate that a compact object there contains about nine times the mass of the Sun and changes its brightness continually on several time scales, at least down to milliseconds. Such behavior is expected for a black hole, and difficult to explain with other models. Pictured above is an artistic impression of the Cygnus X-1 system. On the left is the bright blue supergiant star designated HDE 226868, which is estimated as having about 30 times the mass of our Sun. Cygnus X-1 is depicted on the right, connected to its supergiant companion by a stream of gas, and surrounded by an impressive accretion disk. The bright star in the Cygnus X-1 system is visible with a small telescope. Strangely, the Cygnus X-1 black hole candidate appears to have formed without a bright supernova explosion.
说明: 这是颗黑洞吗？很可能！双星系统天鹅座X-1是最佳的恒星黑洞候选者之一。这个系统会被发现，是因为它是天空最明亮的X射线源之一，因此在天文学家开始探索未知X射线天空时，立即就被搭载特殊相机的控空火箭所侦测到。这个恒星系统的得命名，来自它是北天 天鹅座内最亮的X射线源。数据显示，这个系统有颗质量大约是太阳九倍的致密天体，而且有多个不同时间尺度的变光周期，最短的只有数毫秒。这些都是黑洞的预期行为，而且很难用其他的天体模型加以解释。上面图片是画家为天鹅座X-1所描绘的想像画，左方是颗编录号为HDE 226868的明亮蓝超巨星，它的质量约是太阳的三十倍，影像右方则是想像中的天鹅座X-1，它和超巨星伴星之间以物质流相连结，而周围有一个壮丽的吸积盘。天鹅座X-1系统内的蓝色亮星，用小型望远镜就能看见。有意思的是，天鹅座X-1这颗黑洞候选者，可能并不是经由一次明亮的超新星爆炸而产生的。
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 August 12
[img]http://www.bjp.org.cn/images/2008-08/13/xin_bbb296ca482346fd84ec164604ddb699_marsapan_phoenix_compressed.jpg[/img]
A Mars Panorama from the Phoenix Lander
凤凰号着陆器拍摄到的火星全景影像
Credit: Phoenix Mission Team, NASA, JPL-Caltech, U. Arizona
影像提供：Phoenix Mission Team, NASA, JPL-Caltech, U. Arizona
Explanation: If you could stand on Mars, what would you see? The robotic Phoenix spacecraft that just landed on Mars in May recorded the above spectacular panorama. The above image is actually a digital combination of over 100 camera pointings and surveys fully 360 degrees around the busy robotic laboratory. Clicking on the horizontally compressed image above will bring up the extra-wide uncompressed version. Visible in the image foreground are circular solar panels, various Phoenix instruments, rust colored rocks, a trench dug by Phoenix to probe Mars' chemical composition, a vast plateau of dirt and dirt-covered ice, and, far in the distance, the dust colored atmosphere of Mars. Phoenix landed in the far north of Mars and has been using its sophisticated laboratory to search for signs that past life might have been possible. Recent soil analyses have confirmed the presence of ice, but gave conflicting indications of unexpected perchlorate salts. Whether perchlorates exist on Mars is now being aggressively researched, as well as what effects perchlorates might have had on the past development of life.
影像提供：Phoenix Mission Team, NASA, JPL-Caltech, U. Arizona
说明：如果你能站在火星上，你会看到什么？5月份，在凤凰号飞船在刚刚着陆在火星上时就拍摄到了上面这张壮观的全景影像。上面这张影像实际上是一张由100多张影像，经过探测器周围360度全景拍摄而合成的。点击上面这张经过压缩了的火星地平线影像，就能下载一张极度宽广且没被压缩了版本。可以看到影像前景中的是圆形的太阳能电池板，凤凰号上形式各样的设备，锈色斑斑的岩石，还有凤凰号探测器探测火星土壤化学成分时所挖的坑，由泥土和泥土覆盖冰块组成的广阔高原，还有在遥远处火星上满是尘埃的大气层。凤凰号着陆在火星的最北方，并且已经利用它那先进的实验设备来寻找过去可能存在生命的记号。最近的土壤分析证明火星上有冰存在，但对火星上是否存在高氯酸盐并不确定。在全力寻找高氯酸盐的同时，高氯酸盐对古代生命有些什么影响也是探索的目的。
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 August 13
[img]http://www.bjp.org.cn/images/2008-08/13/xin_dc459b28009342a7bf653b53608201a1_NGC6888_hallas_c800.jpg[/img]
NGC 6888: The Crescent Nebula
NGC6888：新月星云
Credit & Copyright: Tony Hallas
影像提供及版权：Tony Hallas
Explanation: NGC 6888, also known as the Crescent Nebula, is a cosmic bubble about 25 light-years across, blown by winds from its central, bright, massive star. This beautiful telescopic view combines a composite color image with narrow band data that isolates light from hydrogen and oxygen atoms in the wind-blown nebula. The oxygen atoms produce the blue-green hue that seems to enshroud the detailed folds and filaments. NGC 6888's central star is classified as a Wolf-Rayet star (WR 136). The star is shedding its outer envelope in a strong stellar wind, ejecting the equivalent of the Sun's mass every 10,000 years. The nebula's complex structures are likely the result of this strong wind interacting with material ejected in an earlier phase. Burning fuel at a prodigious rate and near the end of its stellar life this star should ultimately go out with a bang in a spectacular supernova explosion. Found in the nebula rich constellation Cygnus, NGC 6888 is about 5,000 light-years away.
说明：NGC6888，也被称为新月星云，是一个大小约25 光年的宇宙泡泡，由其内明亮的大质量中央恒星吹出。这张美丽的望远镜影像是一张色彩合成的窄波段数据影像，分离了这个星云内氢和氧原子发出的光。氧原子产生蓝绿辉光，似乎体现了星云细致褶皱和灯丝状物质。NGC6888的中央恒星被归类为一颗沃尔夫－拉叶星（WR136）。这颗恒星正吹出强烈的恒星风将其外壳吹走，每1万年喷射出的质量相当于一个太阳的质量。星云的复杂结构可能是强烈恒星风和在早期阶段喷射出的物质相互作用的结果。以巨大的速率燃烧物质以及处于恒星生命的最后阶段，都会使这颗恒星最终发生壮观的超新星爆炸结束它的生命旅程。NGC6888位于星云富集的天鹅座内，距离我们大约5,000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 August 14
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/Perseid_pacholka_750wp.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod_e/image/0808/Perseid_pacholka_750wp.jpg[/img][/url]
Perseid Trail
英仙座流星
Credit & Copyright: Wally Pacholka (Astropics.com / TWAN)
影像版权与提供: Wally Pacholka (Astropics.com / TWAN)
Explanation: This bright and colorful meteor flashed through Tuesday's early morning skies, part of the annual Perseid Meteor Shower. The lovely image is one of over 350 frames captured on August 12 from the Joshua Tree National Park, in California, USA . Dust from comet Swift-Tuttle is responsible for the Perseids, creating the northern hemisphere's regular summer sky show. The comet dust is vaporized as it enters the atmosphere at upwards of 60 kilometers per second, producing visible trails that begin at altitudes of around 100 kilometers. Of course, the trails point back to a radiant point in the constellation Perseus, giving the meteor shower its name. Recorded after moonset, the starry background features the bright star Vega on the right. Extending below the western horizon is the faint band of the northern Milky Way.
说明: 这颗来自英仙座流星雨的明亮多彩流星，在星期二掠过了清晨的长空。这幅美丽的影像，是8月12日晚上从美国．加州短叶丝兰国家公园所拍摄的350多张照片之一。当时，来自史威福-塔托彗星的微尘颗粒成群穿过地球大气，形成北半球夏季夜空的奇景--英仙座流星雨。随着彗星的微粒以每秒60公里的高速穿过大气，在一百公里的高空发生汽化并留一道流迹。这些流星迹都回指到英仙座的辐射点，因此这群流星雨就以此命名。上面这幅在月落后拍摄的照片里，背景星空右上方的亮星是织女星，贯过影像并延伸到西方地平线的暗淡带状结构是北天银河。
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 August 15
[img]http://www.bjp.org.cn/images/2008-08/15/xin_0b5c04b0ac9f42748168bcd6ce96d47a_NGC6946_2008wendel800.jpg[/img]
Facing NGC 6946
[b]正面的[/b]NGC6946
Credit & Copyright: Volker Wendel (Spiegelteam)
影像提供及版权：Volker Wendel (Spiegelteam)
Explanation: From our vantage point in the Milky Way Galaxy, we see NGC 6946 face-on. The big, beautiful spiral galaxy is located just 10 million light-years away, behind a veil of foreground dust and stars in the high and far-off constellation of Cepheus. From the core outward, the galaxy's colors change from the yellowish light of old stars in the center to young blue star clusters and reddish star forming regions along the loose, fragmented spiral arms. NGC 6946 is also bright in infrared light and rich in gas and dust, exhibiting a high star birth and death rate. In fact, since the early 20th century at least nine supernovae, the death explosions of massive stars, were discovered in NGC 6946. In this deep color composite image, a small barred structure is just visible at the galaxy's core. Nearly 40,000 light-years across, NGC 6946 is also known as the Fireworks Galaxy.
说明：从银河系有利的位置看去，我们正好能看到NGC6946的正面。这一巨大而又美丽的旋涡星系距离我们仅仅1,000万光年远，位于仙王座内一片前景星尘纱幕的后方。从星系中央往外，沿着断断续续的疏散旋臂，星系的颜色逐渐变换，从中央年老恒星发出的黄色光辉到年轻蓝色星团和泛红色恒星形成区域。在红外光线下，NGC6946也很明亮，其内富含气体和尘埃，恒星诞生和死亡几率都很高。事实上，自从20世纪初开始，至少有9次超新星爆发，也就是大质量恒星的死亡爆炸，都被发现在NGC6946内。在这张深空彩色合成影像中，在星系中央可以看到细小的棒状结构。NGC6946大小近4万光年，也被称为焰火星系。
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 August 16
[url=http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod/image/0808/P305-9591_P306-1976_FF.jpg][img]http://www.phys.ncku.edu.tw/~astrolab/mirrors/apod/image/0808/P305-9591_P306-1976_FF800r.jpg[/img][/url]
Perseid over Vancouver
加拿大．温哥华市上空的英仙座流星
Credit & Copyright: Yuichi Takasaka ([url=http://www.blue-moon.ca][color=black]www.blue-moon.ca[/color][/url] / TWAN)
影像版权与提供: Yuichi Takasaka ([url=http://www.blue-moon.ca][url=http://www.blue-moon.ca/][color=black]www.blue-moon.ca[/color][/url][color=black]/[/color][/url] TWAN)
Explanation: Colorful and bright, the city lights of Vancouver, Canada are reflected in the water in this portrait of the world at night. Recorded on August 12 during the Perseid Meteor Shower, the wide-angle view takes in a large swath along the photographer's eastern horizon. The picture is a composite of many consecutive 2 second exposures that, when added together, cover a total time of an hour and 33 minutes. During that time, stars trailed through the night sky above Vancouver, their steady motion along concentric arcs a reflection of planet Earth's rotation. The dotted trails of aircraft also cut across the scene. Of course, two of the frames captured the brief, brilliant flash of a Perseid fireball as it tracked across the top of the field of view. The large gap in the single meteor trail corresponds to the time gap between the consecutive frames.
说明:这张来自世界夜晚的影像里，加拿大．温哥华市明亮多彩的都市灯火倒映在水面上。这幅呈现了大片地平线景观的广角影像，同时也记录了8月12日的英仙座流星雨。影像是由非常多张二秒曝光的照片叠加起来的，总和的时间有一小时33分钟。在这段期间，恒星拖着弧状的流迹移过温哥华市的星空，它们规律的同心圆弧轨迹是地球自转的结果，而切过影像的点状流迹则来是自飞机。其中有两幅照片，在二颗明亮的英仙座火流星掠过影像上方的视野时捕捉了它们的踪迹。每一道流星迹上的断痕，则是流星恰好横跨两幅照片所产生的间隙。
