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[视图资料] Astronomy Picture of the Day 2011 每日天文一图第五季(第五季至此结束)

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CDer:000024255
 楼主| 发表于 2011-01-31 17:55 | 显示全部楼层
2011 January 31

Japan's Kounotori2 Supply Ship Approaches the Space Station
Credit: Expedition 26 Crew,NASA
Explanation: The care package from Earth had arrived.Last week, Japan launched the robotic Kounotori2 spacecraft to bring needed supplies, including food, to the International Space Station (ISS).  Kountori2 launched from Japan's Tanegashima Space Center a little over a week ago reached the ISS in low Earth late last week. Pictured above, Kountori2 approached the ISS and was about to be grabbed by astronauts with the Canadarm2 and attached to the Harmony Module.In the above picture as seen through a window on the ISS, the limb of the Earth is visible, including white clouds, blue water, and various tan colored landforms.  In addition to launches including humans, as many as ten robotic spacecraft may be launched to the space station this year, potentially including spacecraft from Russia, Europe, Japan, and a private company in the USA.
说明:来自地球的关爱包裹终于到达了。上周,从日本发射的Kounotori2飞船携带着包括食品在内的补给到达了国际空间站ISS)。在一个多星期前从日本种子岛宇宙中心发射升空Kounotori2于上周末到达了位于地球低空轨道上的ISS。在上面的影像中,Kounotori2靠近ISS,宇航员即将操作加拿大2机器臂捕获飞船并使之与和谐号节点舱对接。透过ISS的窗户,在影像里可以看到地球上的风景,白云、蓝色的海洋、各种色彩的地形。除了运送宇航员之外,今年计划还将发射10次飞船飞往ISS,分别来自俄罗斯欧洲,日本以及美国的一架私人公司
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 楼主| 发表于 2011-02-02 02:19 | 显示全部楼层
本帖最后由 jadiyd 于 2011-2-2 02:21 编辑

今天又是视频,墙内无法观看,暂停
另春节期间无法保证及时更新...还请谅解
最具影响力军事论坛-超级大本营军事论坛欢迎你!超然物外,有容乃大。
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 楼主| 发表于 2011-02-02 22:55 | 显示全部楼层
2011 February 2

Moon and Venus Over Switzerland
Credit & Copyright: David Kaplan
Explanation: Sometimes a morning sky can be a combination of serene and surreal.  Such a sky perhaps existed before sunrise this past Sunday as viewed from a snowy slope in eastern Switzerland.  Quiet clouds blanket the above scene, lit from beneath by lights from the village of Trübbach.  A snow covered mountain, Mittlerspitz, poses dramatically on the upper left, hovering over the small town of Balzers, Liechtenstein far below.  Peaks from the Alps can be seen across the far right, just below the freshly rising Sun.Visible on the upper right are the crescent Moon and the bright planet Venus.Venus will remain in the morning sky all month, although it will likely not be found in such a photogenic setting.
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发表于 2011-02-03 13:52 | 显示全部楼层
好漂亮的图片,伟大的自然,神秘的宇宙!
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 楼主| 发表于 2011-02-03 18:30 | 显示全部楼层
2011 February 3

Six Worlds for Kepler-11
Illustration Credit: Tim Pyle, NASA
Explanation: Six worlds orbit Kepler-11,a sunlike star 2,000 light-yearsdistant in the constellation Cygnus.The new discovery, based on data from NASA'splanet hunting Kepler spacecraft,makes the Kepler-11 systemthe fullest exoplanetary system known.Compared to our Solar System in this illustration,five of Kepler-11's planets orbit closer to their parent star than theMercury-Sun distance, withorbital periods ranging from 10 to 47 days.All six are larger than Earth and are likely composed of mixtures ofrocky material and gas.Their presence, sizes, and masses have been determined by carefullywatching the planets dim the light of Kepler-11 whiletransiting orcrossing in front of the star itself.In fact, in August 2010, Kepler's telescope and camerarecorded a simultaneous transit of three of the planets in the system.As announced yesterday,using the transit techniquethe Kepler mission has now identified over1200 exoplanet candidates in afield of viewthat covers only about 1/400th of the sky.The tantalizing result suggests there are manyundiscoveredplanets orbiting the stars inour galaxy.
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 楼主| 发表于 2011-02-04 20:07 | 显示全部楼层
2011 February 4

Zeta Oph: Runaway Star
Credit: NASA, JPL-Caltech,WISE Team
Explanation: Like a ship plowing through cosmic seas,runaway star Zeta Ophiuchiproduces the arcing interstellar bow wave or bow shock seen in thisstunning infrared portraitfrom the WISE spacecraft.In the false-color view, bluish Zeta Oph, a star about 20 times moremassive than the Sun, lies near the center of the frame, movingtoward the top at 24 kilometers per second.Its strong stellar wind precedes it, compressing and heating the dustyinterstellarmaterial and shaping the curved shock front.Around it are clouds of relatively undisturbed material.What set this star in motion?Zeta Oph was likely once a member of abinary star system, itscompanion star was more massive and henceshorter lived.When the companionexplodedas a supernova catastrophically losing mass,Zeta Oph was flung out of the system.About 460 light-years away, Zeta Oph is 65,000 times moreluminous than the Sun and would be one of the brighter starsin the sky if it weren't surrounded by obscuring dust.The WISEimage spans about 1.5 degrees or 12 light-yearsat the estimated distance ofZeta Ophiuchi.
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发表于 2011-02-04 22:01 | 显示全部楼层
4827295850588116194.jpg
3900961702233483893.jpg
2306687434144366454.jpg
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 楼主| 发表于 2011-02-05 23:08 | 显示全部楼层
2011 February 5

Apollo 14: A View from Antares
Credit: Edgar Mitchell,Apollo 14, NASA;Mosaic -Eric M. Jones
Explanation: Forty years ago,while looking out the window of Apollo 14'sLunar Module Antares, astronautEd Mitchell snappedaseries of photos of the lunar surface,assembledinto this detailed mosaic byApollo LunarSurface Journal editor Eric Jones.The view looks across theFra Mauro highlands to the northwestof the landing site after the Apollo 14 astronauts had completedtheir second and finalwalkon the Moon.Prominent in the foreground is their Modular Equipment Transporter(MET),a two-wheeled, rickshaw-like device used to carry tools and samples.Near the horizon at top center is a 1.5 meter wide boulder dubbedTurtle rock.In the shallow crater below Turtle rockis the long white handle of a sampling instrument,thrown there javelin-style by Mitchell.Mitchell's fellow moonwalker and first American in space,Alan Shepard, also used a makeshift six iron tohit two golf balls.One of Shepard's golf balls is just visible asa whitespot below Mitchell's javelin.
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 楼主| 发表于 2011-02-06 17:01 | 显示全部楼层
2011 February 6

An Anomalous SETI Signal
Credit & Copyright: SETI League
Explanation: No one knows for sure what caused this signal.  There is a slight possibility that it just might originate from an extraterrestrial intelligence.The bright colors on the blue background indicate that an anomalous signal was received here on Earth by a radio telescope involved in a Search for Extraterrestrial Intelligence (SETI).  A search for these signals is ongoing by several groups including volunteer members of the SETI League.  Time labels the vertical axis of the above plot, and frequency marks the horizontal axis.  Although this strong signal was never positively identified, astronomers have identified in it many attributes characteristic of a more mundane and ultimatelyterrestrial origin.  In this case, a leading possibility is that the signal originates from an unusual modulation between a GPS satellite and an unidentified Earth-based source.Many unusual signals from space remain unidentified.  No signal has yet been strong enough or run long enough to be unambiguously identified as originating from an extraterrestrial intelligence.
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 楼主| 发表于 2011-02-07 13:12 | 显示全部楼层
2011 February 7

Sun 360: STEREO Captures Views of the Entire Sun
Credit: STEREO Project,NASA
Explanation: For the first time, the entire Sun is being imaged all at once.This has become possible because the twoSTEREO satellites orbiting and monitoring the Sun are now on opposite sides of the Sun.The two satellites have beendrifting apart,as expected, since theirlaunch in 2006, since one satellite orbits slightly closer to the Sun than the other.  The above image shows nearly the entire Sun as it appeared one day last week, a few days before maximum exposure.  Yesterday, the dark gap in the center closed completely, andSTEREO was able to beam back to Earth full 360 degree images of theclosest star.  Full solar images are useful scientifically for a number of reasons, including catching rapidly evolvingflares,coronal mass ejections,tsunamis, andfilaments, no matter where they occur on the Sun,as well as monitoring days-longsunspots andactive regions without losing them as they rotate out of view.Even though theSTEREO satellites will continue to drift apart at about 44 degrees per year,Sun-staring instruments on or near the Earth will augment them to provide a fullview of the Sun for the next several years.
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 楼主| 发表于 2011-02-08 23:07 | 显示全部楼层
2011 February 8

Iridescent Clouds from the Top of the World Highway  
Credit & Copyright: Charles Stankievech & Sophie Springer
Explanation: Why would a cloud appear to be different colors?A relatively rare phenomenon known asiridescent clouds can show unusual colors vividly or a whole spectrum of colors simultaneously.Thesecloudsare formed of smallwaterdroplets of nearly uniform size.When the Sun is in theright position and mostly hidden by thick clouds,thesethinner clouds significantlydiffract sunlight in a nearly coherent manner, with different colors being deflected by different amounts.Therefore,different colorswill come to the observer from slightly different directions.Many clouds start with uniform regions that could showiridescence butquickly become too thick, too mixed,or too far from the Sun to exhibit striking colors.This iridescent cloud was photographed last year from the Top of the World Highway outside Dawson City, in the Yukon Territory in Northern Canada.
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 楼主| 发表于 2011-02-09 21:21 | 显示全部楼层
2011 February 9

NGC 2174: Stars Versus Mountains
Credit: ESA, Hubble, NASA
Explanation: It's stars versus gas mountains in NGC 2174 and the stars are winning.More precisely, the energetic light and winds from massive newly formed stars are evaporating and dispersing the dark stellar nurseries in which they formed.The structures of NGC 2174 are actually much thinner than air and only appear as mountains due to relatively small amounts of opaque interstellar dust.  A lesser known sight in the nebula-rich constellation Orion, NGC 2174 can be found with binoculars near the head of the celestial hunter. About 6,400 light-years distant, the entire glowing cosmic cloud covers an area larger than the full Moon and surrounds loose open clusters of young stars. The above image from the Hubble Space Telescope shows a dense interior region which spans only about three light years while adopting a color map that portrays otherwise red hydrogen emission in green hues and emphasizes sulfur emission in red and oxygen in blue.Within a few million years, the stars will likely win out completely and the entire dust mountain will be dispersed.
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 楼主| 发表于 2011-02-10 21:44 | 显示全部楼层
2011 February 10

Hanny's Voorwerp
Credit: NASA,ESA,W. Keel (Univ. Alabama),et al.,Galaxy Zoo Team
Explanation: Hanny's Voorwerp,Dutch for "Hanny's Object", is enormous,about the sizeof our own Milky Way Galaxy.Glowing strongly in the greenish light produced byionized oxygen atoms,themysterious voorwerp is belowspiral galaxy IC 2497 in thisview from the Hubble Space Telescope.Both lie at a distance of some 650 million light-years inthe faint constellation Leo Minor.In fact, the enormous green cloud is now suspected to be part of atidal tail of materialilluminated by a quasarinhabiting the center of IC 2497.Powered by a massive black hole, the quasarsuddenly turned off,leaving only galaxy and glowing voorwerpvisible in telescopes at optical wavelengths.The sharp Hubble image also resolves a star forming regionin the voorwerp, seen in yellow on the side near IC 2497.That region was likely compressed by an outflow of gas drivenfrom the galaxy's core.The remarkable mystery object wasdiscovered by Dutch schoolteacherHanny van Arkel in 2007while participating online in the Galaxy Zoo project. Galaxy Zoo enliststhe public to help classifygalaxies found in the Sloan Digital Sky Survey,and more recently in deep Hubble imagery.
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 楼主| 发表于 2011-02-11 17:02 | 显示全部楼层
2011 February 11

Star Colors in Orion
Credit & Copyright: Jens Hackmann
Explanation: What determines a star's color? Its temperature. Red stars are cool, with surface temperatures of around 3,000 kelvins (K), while blue stars are hotter and can have temperatures over 30,000 K. Our own lovely "yellow" Sun's temperature is a comforting 6,000 K. Differences in star colors are particularly easy to see in this intriguing composite view of the constellation Orion, made while experimenting with a star trail step-focus technique. In it, a series of 35 consecutive exposures were combined to produce trails of stars moving left to right through the frame, while changing focus in steps. Beginning and ending with the camera out of focus produced a sharply focused exposure near the middle of the series and blurs the star trails into a bow tie shape. For the brighter stars, blurring produces more saturated colors in the images. At the upper left, Orion's cool red supergiant Betelgeuse stands out from the other, hotter, bluish stars composing the body of the constellation. Not a star at all, the Orion Nebula contributes a pinkish tint below center. Also remarkable in the field, the fainter step focus trail of cool, deep red carbon star W Orionis is near the center right edge, its red hue enhanced by a carbon-rich composition.
说明:是什么因素决定了一颗恒星的颜色?答案是温度!红色恒星温度较低,它的表面温度大约在3000°k,而蓝色恒星则较高,表面温度超过了3°k。而我们可爱的“黄色”太阳温度为6000°k左右。在这张利用星迹分布聚焦技术拍摄到的猎户座合成影像里,很容易分清恒星颜色的不同。连续35张曝光,每次变换焦距记录下了恒星从左至右移动的过程。从开始到结束,变换焦点的相机产生了一张中央的清晰而量变模糊的影像,使得恒星轨迹犹如蝴蝶结状。对于较亮的恒星,产生了更多饱和色彩。在左上方,猎户座较暗的红巨星参宿四与其它更为炽热的蓝色恒星颜色迥异,但共同形成了星座的主体猎户星云并不是一颗恒星,但在影像中央下方形成了一块粉红色斑。还在这片影像中出现的是位于影像中央右边缘附近的深红色碳星猎户座W,其红色辉光是由富碳合成物造成。
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 楼主| 发表于 2011-02-12 15:35 | 显示全部楼层
2011 February 12
Simeis 147: Supernova Remnant
Credit & Copyright: Nobuhiko Miki
Explanation: It's easy to get lost following the intricate filaments in this detailed mosaic image of faint supernova remnant Simeis 147. Also cataloged as Sh2-240 and seen towards the constellation Taurus, it covers nearly 3 degrees (6 full moons) on the sky. That corresponds to a width of 150 light-years at the stellar debris cloud's estimated distance of 3,000 light-years. The remarkable composite includes image data taken through narrow-band filters to highlight emission from hydrogen and oxygen atoms tracing regions of shocked, glowing gas. This supernova remnant has an estimated age of about 40,000 years - meaning light from the massive stellar explosion first reached Earth 40,000 years ago. But this expanding remnant is not the only aftermath. The cosmic catastrophe also left behind a spinning neutron star or pulsar, all that remains of the original star's core.
说明:在这张清晰的影像出现的是昏暗的超新星遗迹Simeis147,看着复杂的灯丝状物质很容易就会迷失。该遗迹被编录为Sh2-240,位于金牛座方向上,在天空中覆盖近3度(6个满月大小)。恒星碎片云离我们大约有3000光年,以此估计其在空间中对应的大小约有150光年宽。这张壮观的合成影像透过窄带滤波器拍摄,突出了炽热气体内被激发了的氧原子和氢原子放射出的光芒。这个超新星遗迹年龄大约在4万年左右,这就意味着大质量恒星爆发出的光首次达到地球是在4万年前。但是这个正在扩张中的遗迹并不是唯一的产物,此次宇宙灾变还留下了一个高速旋转的中子星抑或脉冲星,所有这些都是原恒星核的遗留物
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 楼主| 发表于 2011-02-13 19:38 | 显示全部楼层
2011 February 13
Ice Fishing for Cosmic Neutrinos
Credit: NSF / B. Gudbjartsson, IceCube Collaboration
Explanation: Scientists are melting holes in the bottom of the world. In fact, almost 100 holes melted near the South Pole are now being used as astronomical observatories. Astronomers with the IceCube Neutrino Observatory lowered into each vertical lake a long string knotted with basketball-sized light detectors. The water in each hole soon refreezes. The detectors attached to the strings are sensitive to blue light emitted in the surrounding clear ice. Such light is expected from ice collisions with high-energy neutrinos emitted by objects or explosions out in the universe. Late last year, the last of IceCube's 86 strings was lowered into the frezzing abyss, pictured above, making IceCube the largest neutrino detector yet created. Data from a preliminary experiment, AMANDA, has already been used to create the first detailed map of the high-energy neutrino sky. Experimental goals of the newer IceCube include a search for cosmic sources of neutrinos, a search for neutrinos coincident with nearby supernova and distant gamma-ray bursts, and, if lucky, a probe of exotic physical concepts such as unseen spatial dimensions and faster-than-light travel.
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 楼主| 发表于 2011-02-15 00:31 | 显示全部楼层
2011 February 14

The Rosette Nebula

Credit & Copyright: Brian Lula
Explanation: Would theRosette Nebula by any othername look assweet?The bland New General Catalogdesignation of NGC 2237 doesn't appear to diminish the appearance of this flowery emission nebula.Inside the nebula lies anopen clusterof bright young stars designatedNGC 2244.These starsformed about four million years ago from the nebularmaterial and theirstellar winds are clearing a hole in the nebula's center,insulated by a layer of dust and hot gas.Ultraviolet light from thehot cluster stars causes the surrounding nebula toglow.The Rosette Nebula spans about 100light-years across, liesabout 5000 light-years away,and can be seen with a small telescope towards the constellation ofthe Unicorn(Monoceros).

说明:是否有比玫瑰星云更好的名字来表述其美妙?在新总表内该星云被编录NGC2237,但外表上看去并没有减少发射星云的华丽。在星云内有一个由明亮恒星组成的疏散星团--NGC2244。这些恒星诞生于约400万年前,吹出的恒星风在星云中央吹出了一个大洞,分离了尘埃带和炽热气体。从炽热星团放射出的紫外光是周围星云发光的原因。玫瑰星云覆盖约100光年,距离我们大约5000光年远,朝着麒麟座方向上,人们利用小型望远镜就能看到它。祝大家情人节快乐!
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 楼主| 发表于 2011-02-15 23:01 | 显示全部楼层
2011 February 15

The North America Nebula in Infrared
Credit: NASA, JPL-Caltech, L. Rebull (SSC, Caltech); Optical Rollover: DSS, D. De Martin
Explanation: The North America Nebula can do what most North Americans cannot -- form stars. Precisely where in the nebula these stars are forming has been mostly obscured by some of the nebula's thick dust that is opaque to visible light.However, a new view of the North America Nebula in infrared light by the orbiting Spitzer Space Telescope has peered through much of the dust and uncovered thousands of newly formed stars.Rolling your cursor over the above scientifically-colored infrared image will bring up a corresponding optical image of the same region for comparison.  The new infrared image neatly captures young stars in many stages of formation, from being imbedded in dense knots of gas and dust, to being surrounded by disks and emitted jets, to being clear of their birth cocoons.The North America Nebula (NGC 7000) spans about 50light years and lies about 1,500 light years away toward the constellation of the Swan (Cygnus).Still, of all the stars known in the North America Nebula, which massive stars emit the energetic light that gives the ionized  red glow is still debated.

说明:北美洲星云能做到所有北美洲人不能做的事诞生恒星。生成这些恒星的星云区域几乎被星云内的浓重尘埃遮蔽,可见光很难穿透。斯皮策太空望远镜利用红外光北美洲星云拍摄了一张新的影像,透过尘埃拍到了成千上万颗新诞生的恒星。将鼠标放在上面这张科学着色的红外影像上,就会出现一张相同区域的对应光学影像新红外影像恰好捕捉到了处于形成阶段中的年轻恒星,埋藏于致密气体和尘埃所组成的节点内,周围被盘状物围绕,并且放射出喷流,直到清除茧状结构为止。北美洲星云(NGC7000大小约50光年,位于天鹅座内,距离我们大约1500光年远。对于北美洲星云内的所有恒星来说,哪些大质量恒星放射出的高能光使得离子放射出红色辉光仍然处于探究中。
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 楼主| 发表于 2011-02-16 21:39 | 显示全部楼层
2011 February 16

Comet Tempel 1 from Stardust-NeXT Spacecraft
Credit: NASA, JPL-Caltech, Cornell
Explanation: No comet has ever been visited twice before.Therefore, the unprecedented pass of the Stardust-NeXT spacecraft near Comet Tempel 1 earlier this week gave humanity a unique opportunity to see how the nucleus of a comet changes over time.  Changes in the nucleus of Comet Tempel 1 were of particular interest because the comet was hit with an impactor from the passing Deep Impact spacecraft in 2005. Pictured above is one digitally sharpened image of Comet Tempel 1 near the closest approach of Stardust-NeXT.Visible are many features imaged in 2005, including craters, ridges, and seemingly smoother areas.Few firm conclusions are yet available, but over the next few years astronomers who specialize in comets and the understanding the early Solar System will be pouring over these images looking for new clues as to how Comet Tempel 1 is composed, how the 2005 impact site now appears, and how general features of the comet have evolved.

说明:在此前还从没有一颗彗星被访问过两次。因此,在本周早些时候,星尘号探测器掠过坦普尔1号彗星,让人类有机会看到彗星核随着时间推移所发生的变化。坦普尔1号彗星核的变化尤为吸引眼球,因为在2005年彗星受到了深度撞击飞船发出的碰撞器撞击上面是一张数码锐化的影像,显示了在星尘号飞船靠近坦普尔1号彗星时拍摄的景象。可以看到与2005年拍摄时具有许多相同特征,包括撞击坑,隆起,以及看上去较为平坦的区域。如今还没有得出可靠的结论,但是在经后的几年时间里,那些研究彗星以及了解早期太阳系的天文学家们将倾心于这些影像,来寻找关于坦普尔1号彗星的新线索,包括其如何形成,2005年撞击位置如今的变化,以及彗星大体特征如何变化。
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 楼主| 发表于 2011-02-17 17:55 | 显示全部楼层
2011 February 17

X-Class Flare
Credit: NASA /Goddard /SDO AIA Team
Explanation: On Valentine's Day (ET)the Sun unleasedone of its most powerful explosions, anX-class flare.The blast was the largest so far in the new solar cycle.Erupting from active regionAR1158 in the Sun's southern hemisphere,the flare is captured herein this extreme ultraviolet image from theSolar Dynamics Observatory (SDO).The intense burst of electromagnetic radiation momentarily overwhelmedpixels in SDO's detectors causing the bright vertical blemish.This X-class flare was also accompanied by acoronal mass ejection (CME), a massive cloudof charged particlestraveling outward at nearly 900 kilometersper second.Skywatchers at high latitudes should bealert for aurorae tonight.

说明:(美国东部时间)情人节当天,太阳表面爆发了一次能量最大的爆炸--X级耀斑。此次爆发是迄今为止新一轮太阳周期内最大的一次。在太阳南半球表面的AR1158活跃区域内发生,这里出现的影像是由太阳动力观测台(SDO在极紫外光线下拍摄。电磁辐射的强烈爆发暂时掩盖了SDO上检测器的像素,因而在影像上留下了明亮的垂直耀斑。这个X级耀斑还与日冕物质抛射CME)有关,大质量带电微粒云以接近每秒900公里的速度冲出太阳表面。高纬度地区的天文观测者们或许可以留意今晚的极光现象。
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 楼主| 发表于 2011-02-18 18:42 | 显示全部楼层
2011 February 18

Planetary Nebula Project
Credit & Copyright: J-P Metsävainio(Astro Anarchy)
Explanation: Cast off by dying sunlike stars,planetary nebulaeare a brief but glorious final phase of stellar evolution.The gaseous shrouds are ionized by an extremely hot central source,the shrinking core of a star running out offuel for nuclear fusion.Shining in the cosmic night, their simplesymmetriesare fascinating and have inspired thisplanetary nebula poster project.In it, nine planetaries are displayed for comparison in a 3x3 grid.Of course, planetary nebula fans should be able topick out the brightMessier objectsM27 - the Dumbbell Nebula,M76 - the Little Dumbbell, andM57 - the Ring Nebula, as well asNGC 6543, aka the Cat's Eye Nebula.Lesser known nebulae include theMedusa and theBug.All the images were made with detailed narrow band data andare shown at the sameangular scale,spanning 20 arc minutes (1/3 degree).At that scale, the grey circle represents the apparent size ofthe Full Moon.These planetary nebulaehint at the fate of our ownSun as its core runs out of nuclear fuel in another5 billion years.

说明:由频临死亡的类太阳恒星抛出,行星状星云是恒星演变的最后阶段,光辉而又短暂。气体外壳受到极炽热中央源电离后发出辉光,恒星消耗掉核聚变燃料之后形成了收缩在星云中央的射线源。这些简单的对称星云非常迷人,闪烁在宇宙夜空中,因此突发灵感制作了这张行星状星云投影海报。在海报内,9个行星状星云被放置于一个3x3的格子内。当然,行星状星云爱好者能够很容易辨别明亮的梅西耶天体M27哑铃星云,M76小哑铃星云, M57环状星云,以及NGC6543猫眼星云。鲜为人知的星云包括美杜莎星云以及袋状星云。所有影像都来自于细致的窄带数据,并以相同角大小显示,在天空中覆盖约20弧分(1/3度)。在规模上,灰色的圆圈代表满月大小。这些行星状星云暗示50亿年后我们太阳消耗掉核燃料的命运。
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 楼主| 发表于 2011-02-20 01:14 | 显示全部楼层
2011 February 19

Spiral Galaxy NGC 2841 Close Up
Credit: NASA,ESA, and theHubble Heritage(STScI /AURA) -ESA /Hubble Collaboration
Explanation: A mere 46 million light-years distant, spiral galaxy NGC 2841can be found in the northern constellation ofUrsa Major.This sharp view of the gorgeousisland universeshows off a striking yellow nucleus and galactic disk.Dust lanes, small, pink star-forming regions, and young blue star clustersare embedded in the patchy, tightlywoundspiral arms.In contrast, many other spiralsexhibit grand, sweepingarms with large star-forming regions. NGC 2841 has a diameter of over 150,000 light-years, even larger thanour ownMilky Way, but thisclose-up Hubble image spans about34,000 light-years along the the galaxy's inner region.X-ray imagessuggest that resulting winds and stellar explosions createplumes of hot gas extending into a halo around NGC 2841.
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 楼主| 发表于 2011-02-20 13:26 | 显示全部楼层
2011 February 20

Mammatus Clouds Over Olympic Valley
Credit & License: Matt Saal (Wikipedia)
Explanation: What's happened to these clouds?Normal cloud bottoms are flat because moist warm airthat rises and cools will condense into water droplets at a very specific temperature,which usually corresponds to a very specific height.  After waterdroplets form that air becomes an opaque cloud.  Under some conditions, however,cloud pockets can develop that containlarge droplets of water or ice that fall into clear air as they evaporate.  Such pockets may occur inturbulent air near athunderstorm, being seen near the top of ananvil cloud, for example.  Resulting mammatus clouds can appearespecially dramaticif sunlit from the side.  Thesemammatus cloudswere photographed last August over Olympic Valley, California, USA.
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 楼主| 发表于 2011-02-21 22:14 | 显示全部楼层
2011 February 21

Milky Way Over Switzerland
Credit: Stephane Vetter(Nuits sacrees)
Explanation: What's visible in the night sky during this time of year?To help illustrate the answer, a beautiful land, cloud, and skyscape was captured earlier this month overNeuchâtel,Switzerland.Visible in the foreground were the snow covered cliffs of the amphitheater shapedCreux du Van, as well as distant trees, and town-lit clouds.Visible in the night sky (at midnight) were galaxies including thelong arch of the central band of ourMilky Way Galaxy, theAndromeda galaxy (M31), and theTriangulum galaxy(M33.Star clusters visible included NGC 752,M34,M35,M41,the double cluster, andthe Beehive (M44).Nebulas visible included the Orion Nebula(M42),NGC 7822,IC 1396, theRosette Nebula,the Flaming Star Nebula, theCalifornia Nebula, theHeart andSoul Nebulas, and thePacman Nebula.Rolling your cursor over theabove image will bring up labels for all of these.But the abovewide angle sky image captured even more sky wonders.What other nebulascan you find in the above image?

说明:一年的这段时间,在夜空中能看到什么?为了帮助寻找答案,本月初在瑞士纳沙泰尔拍摄了这张美丽的影像,其中有地景,云彩,以及星空。在影像前景中可以看到白雪覆盖的悬崖--类似古罗马竞技场状的Creux du Van,还有远处的树木和被城镇灯光照亮了的云彩。在夜晚(午夜)的天空中可以看到的星系包括拥有长弧状中心带的银河系大麦哲伦星系M31),以及三角座星系(M33)。可见的星团包括NGC752M34M35,M41,双星团,以及蜂巢星团。可见的星云有猎户座星云(M42),NGC7822,IC1396玫瑰星云火焰星云加州星云心与魂星云以及小精灵星云。将鼠标放置于上面影像上,将会出现一张带有标注的影像版本。但是上面这张广角天空影像拍摄到的天体不止这些,你还能发现哪些星云吗?
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 楼主| 发表于 2011-02-22 19:27 | 显示全部楼层
本帖最后由 jadiyd 于 2011-2-22 19:29 编辑

2011 February 22

Star Size Comparisons

Credit & Copyright:
morn1415 (YouTube)
Explanation: How big is our Sun compared to other stars?In a dramatic andpopular video featured onYouTube,the relative sizes of planets and stars are shown from smallest to largest.Theabove video starts withEarth's Moon and progresses through increasingly larger planets in ourSolar System.  Next, theSun is shown along as compared to many of thebrighter stars in our neighborhood of theMilky Way Galaxy.Finally, some of the largest stars known spin into view.Note that the true sizes of most stars outside of the Sun andBetelgeuse are not known by direct observation, but rather inferred by measurements of their perceivedbrightness,temperature, and distance.Although an inspiring learning tool that is mostly accurate,APOD readers are encouraged to complete the learning experience -- and possibly help make future versions more accurate -- bypointing out slight inaccuracies in the video.
说明:与其它恒星相比,我们的太阳到底有多大?在一段生动而又广受欢迎的Youku视频中(点击图片),从小到大你可以看到行星和恒星的相对大小。上面的视频月球开始,之后依次出现太阳系内较大的天体。之后,太阳与许多我们银河系内的临近亮星相比较。最后一些迄今为止已知最大规模的恒星进入视野。记录大多数太阳和参宿四外侧恒星的真实大小并不是通过直接观测得到,而是通过测量它们的亮度温度,以及距离从而推算得出。尽管学习工具几乎大多都准确,但是为了完善学习经验,或许也能帮助未来的版本更为精确,鼓励APOD的读者们指出视频内的细微误差
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 楼主| 发表于 2011-02-23 20:43 | 显示全部楼层
2011 February 23

The Solar System from MESSENGER
Credit: NASA/JHU APL/CIW
Explanation: If you looked out from the center of the Solar System, what would you see?Nearly such a view was taken recently from the MESSENGER spacecraft currently orbiting the Sun from the distance of Mercury.The Sun's planets all appear as points of light, with the closest and largest planets appearing the brightest.The planets all appear to orbit in the same direction and are (nearly) confined to the same great circle around the sky -- the ecliptic plane.Mercury, Venus, Earth, Mars, Jupiter, and Saturn are all visible in the above horizontally compressed image, while the positions of Uranus and Neptune are labeled even though they are too faint to make out.  Pluto, which has had its planetary status recently called into question, is much too faint to see.Earth's Moon is visible, however, as are the Galilean moons of Jupiter.The above image is the reverse of one taken from the outside of the Solar System in 1990 by Voyager 1.MESSENGER, which has flown by Mercury three times now, is on schedule to enter orbit around the Solar System's innermost planet next month.

说明:如果位于太阳系的中心向外看,你会看到什么?在水星的轨道上绕太阳飞行的信使号飞船最近拍摄到了这样一张影像。太阳系内的所有行星在影像内都以亮点显示,距离太阳最近,体积最大的行星最亮。所有行星看起来都以相同方向绕行,几乎在相同的黄道面内绕天空运转。金星地球,火星,木星和土星都出现在经水平压缩的影像里,海王星和天王星已被标注,因为它们非常昏暗难以辨认。水星因为距离太阳太近因而没有在影像中出现,而身份颇受争议的冥王星也难以看到。影像中还可以辨认出月球,以及木星的伽利略卫星影像拍摄的角度正好与1990旅行者1号从太阳系外拍摄的影像相反。信使号飞船已经3飞越水星,预计下月将进入这颗太阳系最内行星的轨道。
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 楼主| 发表于 2011-02-24 15:57 | 显示全部楼层
2011 February 24

NGC 1999: South of Orion
Image Credit &Copyright: Adam Block,Mt. Lemmon SkyCenter,U. Arizona
Explanation: South of the large star-forming region known as theOrion Nebula, lies bright blue reflection nebulaNGC 1999.Also at the edge of theOrion molecularcloud complex some 1,500 light-years distant, NGC 1999'sillumination is provided by theembedded variable star V380 Orionis.The nebula is marked with a dark sideways T-shape near center in thisbroadcosmic vista that spans over 10 light-years.The dark shape was once assumed to be an obscuring dust cloudseen in silhouette against the bright reflection nebula.But recentinfrared imagesindicate the shape is likely a hole blown through the nebulaitself by energetic young stars.In fact,thisregion abounds with energetic young starsproducing jets and outflows that create luminous shock waves.Cataloged as Herbig-Haro (HH) objects, named for astronomersGeorge Herbig and Guillermo Haro,the shocks appear bright red inthis view that includesHH1 and HH2 just below NGC 1999.The stellar jets andoutflows push through the surroundingmaterial at speeds of hundreds of kilometers per second.

说明:在猎户星云的南部有一个明亮的蓝色反射星云NGC1999。该星云位于猎户座复杂分子云的边缘,距离我们大约 1500光年,NGC1999的光芒是隐藏于其内部的变星猎户座V380发出。在这张超过10光年的广阔宇宙影像里,星云中央出现了一个黑色T字状标记。这个黑色标记曾经被认为是一团投射在背景明亮反射星云上的模糊尘埃云。但是最近拍摄到的红外影像说明了该形状是一个由星云内部的高能新星吹出的空洞。事实上,这个区域富集了产生喷流的高能新星,从而形成了明亮的激波。这些激波被编录为赫比格-哈罗天体,以纪念天文学家乔治.哈比格和吉尔莫.哈罗。影像中的HH1HH2就是出现在NGC1999下方的明亮红色激波。恒星喷流以每秒近上千公里的速度穿过周围物质。
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 楼主| 发表于 2011-02-25 17:27 | 显示全部楼层
2011 February 25

NGC 4449: Close-up of a Small Galaxy
Credit: Data -Hubble Legacy Archive,ESA, NASA;Processing -Robert Gendler
Explanation: Grand spiral galaxiesoften seem to get all the glory.Their young, blue star clusters and pink star forming regionsalong sweepingspiral armsare guaranteed to attract attention.But small irregular galaxies form stars too, likeNGC4449, about 12 million light-years distant.Less than 20,000 light-years across, the small island universe issimilar in size, and oftencomparedto our Milky Way's satellitegalaxy, the Large Magellanic Cloud (LMC).This remarkableHubble Space Telescope close-up of thewell-studiedgalaxy was reprocessed to highlight the telltale reddishglow of hydrogen gas.The glow traces NGC 4449's widespread star forming regions, someeven larger than those in the LMC,with enormous interstellar arcs and bubbles blown by short-lived,massive stars.NGC 4449 is a member of agroupof galaxies found in the constellation Canes Venatici.Interactions with the nearbygalaxiesare thought to have influenced star formation in NGC 4449.

说明大型星系往往会得到所有的赞誉。年轻的蓝色星团和粉色的恒星诞生区域沿着旋臂分布开来,异常引人注目。但是小型不规则星系同样是恒星诞生的场所,就像距离我们大约1200万光年远的NGC4449。该小星系略小于2万光年,与我们银河系的卫星星系大麦哲伦星云LMC)相当,因此经常与之进行对比这张精彩的哈勃太空特写影像经过处理突出了由氢气放射出来的红色辉光。辉光弥漫在NGC4449广阔的恒星形成区域,有些恒星诞生区域甚至比大麦哲伦星云内的还大,其内充满了由生命短暂的大质量恒星吹出的星际弧和泡泡。NGC4449是猎犬座内星系群的一员。与附近星系的交互作用影响着NGC4449内恒星的诞生。
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 楼主| 发表于 2011-02-26 17:08 | 显示全部楼层
2011 February 26

Shell Galaxies in Pisces

Image Credit &Copyright:
Stephen Leshin
Explanation: This colorful cosmic skyscapefeatures a peculiar systemof galaxies cataloged as Arp 227 some 100 million light-yearsdistant.Swimmingwithinthe boundaries of theconstellation Pisces,Arp 227 consists of the two galaxiesprominent on the left;the curious shell galaxy NGC 474 and its blue,spiral-armed neighbor NGC 470.The faint, wide arcs orshellsof NGC 474 could have been formed by agravitational encounter with neighbor NGC 470.Alternately the shells could becaused by a merger with asmaller galaxy producing an effect analogous to ripples acrossthe surface of a pond.Remarkably, the large galaxy on the right hand side of the deep image,NGC 467, appears to be surrounded by faint shells too,evidence of anotherinteractinggalaxy system.Intriguing background galaxies are scattered aroundthe field that also includesspiky foreground stars.Of course, those stars lie well within our ownMilky Way Galaxy.The field of view spans 25 arc minutes or about 1/2 degreeon the sky.
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 楼主| 发表于 2011-02-27 21:21 | 显示全部楼层
2011 February 27

Saturn's Hyperion: A Moon with Odd Craters
Credit: Cassini Imaging Team,SSI,JPL,ESA,NASA
Explanation: What lies at the bottom ofHyperion's strange craters?  Nobody's sure.  To help find out, therobot Cassini spacecraft now orbitingSaturn swooped past thesponge-textured moon in 2005 and2010 and took images of unprecedented detail.  An image from the 2005 pass,shown above in false color, shows a remarkable world strewn withstrange craters and agenerally odd surface.   The slight differences in color likely show differences in surface composition.   At the bottom of most craters lies some type ofunknown dark material.  Inspection of the image shows bright features indicating that the dark material might be only tens of meters thick in some places.   Hyperionis about 250 kilometers across,  rotates chaotically,and has a density so low that itmight housea vast system ofcaverns inside.
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 楼主| 发表于 2011-02-28 16:40 | 显示全部楼层
2011 February 28

Red Snow Moon Over Edmonton
Credit & Copyright: Luca Vanzella
Explanation: What's hovering between those buildings?The Moon.  The above image was taken two weeks ago as thefull Snow Moon started to rise aboveEdmonton,Alberta,Canada.The odd coincidence between theangular size of thefar distant Moonand the angular width of nearby buildings created a striking juxtaposition.Backing away from the buildings so to reduce their angular size was a key to planning the image.The temperature was so low, -25C,that plumes of steam rose from neighboring oil refineries.The above image was taken during a momentary break in the plumes.The rising Moon appears red here for the same reason that a settingSun appears red -- because blue light is preferentiallyscattered away by intervening air.In this case, theshimmering steam plumeslikely also caused the Moon to appearslightly compressed.The next full moon, thefull Worm Moon, will occur in mid-March.

说明:在高楼间徘徊着的是什么?月球。这张影像拍摄于两周前,一轮冰月加拿大阿尔伯特埃德蒙顿市上空升起。远处月球视角与附近建筑的视角相结合一起,从而巧妙地形成了这张壮观的影像。远离建筑减小它们形成的视角是拍摄这张影像的关键。气温很低,只有零下25度,那些烟柱来源于下方的炼油厂。上面的影像拍摄于暂停排放气体阶段。这里看到升起的红色月亮跟日落的红色太阳一样,因为蓝光被空气散射殆尽。在这一例子中,发光的烟柱还使得月球看上去有些微微压缩。下一轮满月,又被称为虫月,将发生在三月中旬。

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 楼主| 发表于 2011-03-01 16:03 | 显示全部楼层
2011 March 1  

Discovery Visits the Space Station
Credit: Space Shuttle STS-133 Crew,Space Station Expedition 26 Crew,NASA
Explanation: What's happening outside the space station?A space shuttle has docked.Five days ago, the space shuttle Discovery was launched to the International Space Station, carrying six crew members and the large Leonardo Multi Purpose Logistics Module.Three days ago, as pictured above, the docked shuttle was prepared to be unloaded by the space stations Dextre robot and Canadarm2.The above expansive photo captures much more, however, including Japan's Kibo Experiment Module on the lower right, Earth across the top of the frame, and a seemingly starless backdrop of space in the distance. During the next week, the shuttle and ISS crews are scheduled to permanently attach Leonardo as well as fix and upgrade parts of the ISS.After 38 previous voyages, this is expected to be the last space mission for the Space Shuttle Discovery.

说明:国际空间站外发生了什么?航天飞机对接成功。5天前,发现号航天飞机带着6名组员和巨大的莱昂纳多多用途后勤舱前往国际空间站上面影像的拍摄是三天前航天飞机与空间站对接成功,正准备用空间站上的机器人Dextre和机械臂Canadarm2进行装卸。上面这张广阔的影像里还拍摄到包括右下方日本的Kibo实验舱,蓝色的地球,以及远处没有星迹的太空。在下周,航天飞机和国际空间站成员将对莱奥纳多舱进行安装,并完成国际空间站的升级。在经历了38次飞行之后,此次飞行将是发现号航天飞机最后的空间使命。
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 楼主| 发表于 2011-03-02 16:24 | 显示全部楼层
2011 March 2  

NGC 1499: The California Nebula
Credit & Copyright: Markus Noller(Deep Sky Images)
Explanation: What's California doing in space?  Drifting through the Orion Arm of the spiral Milky Way Galaxy,this cosmic cloudby chance echoes the outline of California on the west coast of the United States.Our own Sun also lies within the Milky Way'sOrionArm, only about 1,500 light-years from the California Nebula.Also known as NGC 1499, the classic emission nebula is around 100 light-years long.On many images, the most prominent glow of the California Nebula isthe red light characteristic of hydrogen atoms recombining with longlost electrons, stripped away (ionized)by energetic starlight.In the above image, however, hydrogen is colored green, while silicon is mapped to red and oxygen mapped to blue. The star most likely providing the energeticstarlight that ionizes much of the nebular gas is the bright, hot, bluish Xi Persei,just outside the right image edge.A regular target for astrophotographers, the California Nebula can be spotted with a wide-field telescope under a dark skytoward the constellation of Perseus, not far from the Pleiades.

说明:加利福尼亚在太空中做什么?这片宇宙星云徜徉在银河系的猎户臂上,与美国西海岸的加利福尼亚州轮廓近似。我们太阳同样也位于银河系的猎户臂上,与加州星云距离仅为1500光年。该典型的发射星云大约有100光年长,被编录为NGC1499。在许多影像中,加州星云最为主要的辉光是由氢原子与电子重新结合后发出的红光,先前高能星光电离了原子中的电子。上面的影像中,氢原子为绿色,而硅绘为红色,氧为蓝色。电离星云内气体的光芒大多数来自于明亮炽热的泛蓝色恒星—英仙座Xi,该恒星位于影像右侧边缘外。作为天文摄影师的常规观测目标,人们使用广角望远镜在黑暗的夜空下朝向英仙座能找到它,离昴星团并不远。
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 楼主| 发表于 2011-03-03 17:40 | 显示全部楼层
2011 March 3

Lunar Nearside
Credit: NASA /GSFC /Arizona State Univ. /LunarReconnaissance Orbiter
Explanation: About 1,300 images from the Lunar Reconnaissance Orbiterspacecraft's wide angle camera were used to compose thisspectacular view of afamiliar face -the lunar nearside.But why is there a lunar nearside?TheMoon rotates on its axis andorbitsthe Earth at the same rate, about once every 28 days.Tidally lockedin this configuration, thesynchronous rotation always keeps one side, the nearside,facing Earth.As a result, featured in remarkable detail in thefull resolution mosaic,the smooth, dark,lunar mare (actually lava-flooded impact basins),and rugged highlands, are well-knownto earthbound skygazers.To find your favoritemare or large crater, just slide your cursor overthe picture.The LRO imagesused to construct the mosaic were recorded overa two week period last December.

说明:月球勘测轨道飞行器拍摄的约1300张广角影像被用于合成这张壮观而又令人熟悉的画面—月球的近地面。但是为什么仅仅是月球的近地面呢?月球以轴自转并且以相同的速率绕地球转动,周期为28天。潮汐引力造成了这种现状,同步绕转使得近地面一侧永远面向地球。出现在这张高分辨率影像中的有平滑的黑暗月海(实际上是熔岩状撞击盆地)和隆起的高地,这些都为观测者们所熟知。将鼠标放到照片上,就会出现你所中意的月海或者环形山。被用来合成这张马赛克的月球勘测轨道飞行器影像拍摄于去年12月,为期两周多。
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 楼主| 发表于 2011-03-04 17:06 | 显示全部楼层
2011 March 4

NGC 6914 Nebulae
Credit: Descubre Foundation,CAHA,OAUV,DSA,Vicent Peris (OAUV),Jack Harvey (SSRO),Juan Conejero (PixInsight)
Explanation: A dramatic study in contrasts,this colorful skyscape features stars,dust, and glowing gas in NGC 6914.The complex of nebulae lies some 6,000 light-years away, toward thehigh-flying northern constellationCygnus and the plane of ourMilky Way Galaxy.With foreground dust clouds in silhouette, both reddish hydrogenemission nebulae and dusty bluereflection nebulae fill the 1/2 degreewide field of view that spans nearly 50 light-yearsat the esitmated distance of NGC 6914.Ultraviolet radiation from the massive, hot, young stars of theextensiveCygnus OB2association ionize the region's atomichydrogen gas, producingthe characteristic red glow as protons and electrons recombine.Embedded Cygnus OB2 stars also provide theblue starlight strongly reflected by the dusty clouds.Constructed as a two-panel mosaic, the image wasprocessedto bring outboth bright and dim colors and detailed structures.

说明这片华丽的天空突出了NGC6914内的恒星,尘埃以及炽热气体,位于天鹅座内,处于距离我们6000光年远的银河系盘面上。前景中的尘埃云,泛红色的发射星云以及尘埃状蓝色发射星云充满了这张广角影像,在天空中覆盖约1/2度,于NGC6914的估计距离计算,该影像大约近50光年。来自大质量炽热新星放射出的紫外射线电离了该区域内的氢气,当原子与电子重新结合后,又产生了典型的红色辉光。在天鹅座OB2内的恒星还发出了能被周围的尘埃云气强烈反射的蓝色星光。由两张马赛克影像构成,这张影像给大家带来了明暗色彩以及清晰的结构特征。
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 楼主| 发表于 2011-03-05 16:12 | 显示全部楼层
2011 March 5

Cooling Neutron Star
Credit: X-ray: NASA /CXC /UNAM / Ioffe /D.Page,P.Shternin et al;Optical: NASA /STScI;
Illustration:NASA/CXC/M.Weiss)
Explanation: Supernova remnantCassiopeia A (Cass A) is acomfortable11,000 light-years away.Light from the Cass A supernova,the death explosion of a massive star,first reached Earth just 330 years ago. The expanding debris cloud spans about 15 light-years inthis compositeX-ray/optical image,while the bright source near the center is aneutron star(inset illustration)the incredibly dense, collapsed remains of the stellar core.Still hot enough to emit X-rays, Cass A's neutron star is cooling.In fact, 10 years of observations with the orbitingChandra X-ray observatory find thattheneutron star is coolingrapidly, so rapidly that researchers suspect a large part ofthe neutron star's core is forming a frictionlessneutron superfluid.The Chandra results represent the first observational evidence for thisbizarre state of matter.
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 楼主| 发表于 2011-03-06 15:46 | 显示全部楼层
2011 March 6  

Asteroids in the Distance
Credit: R. Evans & K. Stapelfeldt(JPL), WFPC2,HST,NASA
Explanation: Rocks from space hit Earth every day.  The larger the rock, though, the less often Earth is struck.  Many kilograms of space dust pitter to Earth daily.Larger bits appear initially as a bright meteor.  Baseball-sized rocks and ice-ballsstreak through our atmosphere daily,most evaporating quickly to nothing.  Significant threats do exist for rocks near100 meters in diameter, whichstrike the Earthroughly every 1000 years.  An object this size could cause significanttsunamis were it to strike an ocean,potentially devastating even distant shores.A collision with a massive asteroid,over 1 km across, is more rare,occurring typically millions of years apart, butcould have truly global consequences.Many asteroids remainundiscovered.  In fact, one was discovered in 1998 as the long blue streak in theabove archival image taken by the Hubble Space Telescope.In 2002 June,the small 100-meter asteroid2002 MN was discovered only after itwhizzed by the Earth,passingwell within the orbit of the Moon.2002 MN passed closer than any asteroid since1994 XM1, but not as close as2004 MN4 will pass in 2029.A collision with a large asteroid  would not affect Earth's orbit so much asraise dustthat would affect Earth's climate.  One likely result is a global extinction of many species of life,possibly dwarfing the ongoingextinction occurring now.
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 楼主| 发表于 2011-03-07 17:16 | 显示全部楼层
2011 March 7   



A Solar Prominence Eruption from SDO
Credit: NASA/Goddard/SDO AIA Team

Explanation: One of the most spectacular solar sights is an erupting prominence.Two weeks ago, NASA's Sun-orbitingSolar Dynamic Observatory spacecraft imaged animpressively large prominenceerupting from the surface.The dramatic explosion was captured in ultraviolet light in theabove time lapse video covering 90 minutes,where a new frame was taken every 24 seconds.  The scale of the prominence is huge -- the entire Earth would easily fit under the flowing  curtain of hot gas.  A solar prominence is channeled and sometimes held above theSun's surface by the Sun'smagnetic field.A quiescent prominence typically lasts about a month, and may erupt in aCoronal Mass Ejection (CME)expelling hot gas into theSolar System.  The energy mechanism that creates asolar prominence is still a topic ofresearch.  As the Sun progresses towardSolar Maximumin the next few years,solar activity likeeruptive prominences are expected to become more common.

说明:太阳表面最为壮观的景象之一就是爆发日珥。两周前,绕太阳飞行的NASA太阳动力学观测卫星拍摄到一道从太阳表面喷出的巨大日珥。此次惊人的爆发拍摄于紫外光下,整段延时视频大约有90分钟,每一帧大约有24秒。日珥爆发的规模巨大,地球整个都能轻松放置于炽热气体形成的幕帘下。由于太阳的磁场存在,爆发的日珥有时候滞留在太阳表面。比较宁静的日珥持续的时间大约一个月,并且许多日珥发生于向太阳系内喷射炽热气体的日冕物质抛射内。形成日珥的高能原理依旧是研究的课题。在今后几年里,当太阳向太阳活动极大期靠近时,类似日珥喷发这样的太阳活动将会越来越频繁。
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 楼主| 发表于 2011-03-08 21:49 | 显示全部楼层
2011 March 8  

Titan, Rings, and Saturn from Cassini
Credit: Cassini Imaging Team,ISS,JPL,ESA,NASA
Explanation: How thin are the rings of Saturn?  Brightness measurements from different angles have shown Saturn's rings to be about one kilometer thick, making them many times thinner, in relative proportion, than a razor blade.  This thinness sometimes appears in dramatic fashion during an image taken nearly along the ring plane.  The robot Cassini spacecraft now orbiting Saturn has now captured another shot that dramatically highlights the ring's thinness.  The above image was taken in mid January in  infrared and polarized light.Titan looms just over the thin rings, while dark ring shadows on Saturn show the Sun to be above the ring plane.Close inspection of the image will show the smaller moon Enceladus on the far right.Cassini, humanity's first mission to orbit Saturn, currently has operations planned until 2017.

说明:土星光环到底有多稀薄?土星光环大约有1公里厚,相比较而言,它就像人类使用的剃须刀片一样薄。沿着光环的盘面拍摄,这种生动的比喻有时就会显而易见卡西尼飞船正绕土星飞行,前不久拍摄了另一幅生动的影像,时间为一月中旬,在红外光偏振光下获得。土卫六位于稀薄光环的上方,而光环的阴影映射在土星上,阴影的位置说明太阳也位于光环盘面上方。仔细观查这张影像就会发现影像最右侧还有一颗更小的卫星--土卫二。作为人类绕行土星的首次使命,目前卡西尼飞船的飞行计划将运行到2017年。
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 楼主| 发表于 2011-03-09 18:01 | 显示全部楼层
2011 March 9  

The International Space Station Expands Again
Credit: STS-133 Shuttle Crew,NASA
Explanation: The developingInternational Space Station (ISS) has changed its appearance again.  In a recently completed rendezvous, theSpace Shuttle orbiterDiscovery, in its final flight, visited the ISS and added components that included theLeonardo Multi Purpose Logistics Module.The ISS and many of its modules and expansive solar panels are visible inthe above picture taken by the Discovery Crew after leaving theISSto return to Earth.  The world's foremostspace outpost can be seen developing over the past several yearsby comparing the above imagetoother pastimages.  Also visible above are manydifferent types of modules and supply ships.  Construction began on the ISS in 1998.

说明国际空间站的扩建再次改变了其外观。发现号航天飞机与国际空间站最近完成的一次对接,为国际空间站增添了部分组件,其中包括莱昂纳多多用途后勤舱。此次访问国际空间站也是发现号航天飞机最后的飞行使命。在上面这张影像中出现的是国际空间站及其组件,还有伸展的太阳能电池板,发现号组员在离开国际空间站返回地球时拍摄了这张壮观的影像。作为世界的太空前哨站,通过与过去几年拍摄到的影像作对比,国际空间站的外观发生了很大变化。国际空间站的建设从1998年开始,在上面影像中还可以看到不同类型的舱体补给船

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