2024年01月16日:肉眼几乎可见的猎户座-（The Orion You Can Almost See） [2024年01月16日:肉眼几乎可见的猎户座-（The Orion You Can Almost See）--原图下载](https://apod.nasa.gov/apod/image/2401/OrionMcc_Guzzini_1366.jpg"onMouseOver="if (document.images)document.imagename1.src='image/2401/OrionMcc_Guzzini_960_annotated.jpg';"onMouseOut="if (document.images)document.imagename1.src='image/2401/OrionMcc_Guzzini_960.jpg';){mtitle title="肉眼几乎可见的猎户座"/}Image Credit & Copyright: Michele Guzzini说明: 你认得这个星座吗？儘管它是天空中最容易辨认的星群之一，但这种与肉眼所见比较更加完整的猎户座，只有透过长曝光数位相机成像及电脑后製处理才得以显现。在此影像里，带着深橙色调的低温红巨星参宿四，是位于左上角的最明亮恒星。猎户座的炽热泛蓝恒星数量众多，其中，右下角的超巨星参宿七，亮度足以和左上角的参宿四相抗衡，而右上角的亮星则是参宿五。距离我们全约为1,500光年远的猎户腰带三星，皆诞生于猎户座备受研究的星际云里。猎户腰带下方有一片明亮但模糊的光斑，它看来或许也有点眼熟，这是因为它是名为猎户大星云的恒星孕育室。最后是肉眼勉强可见但相当引人注目的巴纳德环，这团环拱在猎户腰带和猎户大星云周围的庞大发射星云，是由猎户座摄影先锋巴纳德发现于100多年前。（Betelgeuse 参宿四; Rigel 参宿七; Bellatrix 参宿五; Barnard's Loop 巴纳德环; Hatysa 伐三; Alnitak 参宿一; Alnilam 参宿二; Mintaka 参宿三; Saiph 参宿六; Cursa 玉井三-波江座）{lamp/}原文：{mtitle title="The Orion You Can Almost See"/}Image Credit & Copyright: Michele GuzziniExplanation: Do you recognize this constellation? Although it is one of the most recognizable star groupings on the sky, this is a more full Orion than you can see -- an Orion only revealed with long exposure digital camera imaging and post-processing. Here the cool red giant Betelgeuse takes on a strong orange tint as the brightest star on the upper left. Orion's hot blue stars are numerous, with supergiant Rigel balancing Betelgeuse on the lower right, and Bellatrix at the upper right.Lined up in Orion's belt are three stars all about 1,500 light-years away, born from the constellation's well-studied interstellar clouds.Just below Orion's belt is a bright but fuzzy patch that might also look familiar -- the stellar nursery known as Orion's Nebula. Finally, just barely visible to the unaided eye but quite striking here is Barnard's Loop -- a huge gaseous emission nebula surrounding Orion's Belt and Nebula discovered over 100 years ago by the pioneering Orion photographer E. E. Barnard.

2023年12月31日:揭示计画的宇宙模拟影片-（Illustris: A Simulation of the Universe） 2023年12月31日:揭示计画的宇宙模拟影片-（Illustris: A Simulation of the Universe）--原图下载2023 December 31 {mtitle title="揭示计画的宇宙模拟影片"/}Video Credit: Illustris Collaboration, NASA, PRACE, XSEDE, MIT,Harvard CfA; Music: The Poisoned Princess (Media Right Productions)说明: 我们是怎么来的？请点选"播放"，来观看这部攸关宇宙演化的电脑模拟，以及它对星系形成和人类在宇宙中该如何定位所提出的见解。揭示计画（the Illustris project）在2014年，动用了2千万个计算元运算时数，追蹤边长3千5百万光年的立方体内，120亿个组成元在130亿年期间的演化。在这项模拟里，科学家追蹤物质如何形成各式各样的星系。随着虚拟宇宙演化，部份随着宇宙膨胀的物质，很快地在重力的作用下聚成丝状天体、星系和星系团。这部主题影片以虚拟环绕相机的观点，呈现变动的局部宇宙里的一些天体。首先是暗物质的演化，接着是不同温度下的氢气云（0:45）如何变化，然后是氦和碳这类重元素的形成（1:30），最后再回到暗物质（2:07）。影格的左下角明列大爆炸后的时间，而右下角则标示所呈现的物质类别。爆发事件（例如在0:50），则呈现被星系核心超大质量黑洞喷出的泡状炽热气体。而揭示计画宇宙和真实宇宙所存在的有趣差异，也是研究的课题，诸如为何这项模拟会产生过量的年老恒星。{lamp/}原文：{mtitle title="Illustris: A Simulation of the Universe"/}Video Credit: Illustris Collaboration, NASA, PRACE, XSEDE, MIT,Harvard CfA; Music: The Poisoned Princess (Media Right Productions)Explanation: How did we get here?Click play, sit back, and watch. A computer simulation of the evolution of the universe provides insight into how galaxies formed and perspectives into humanity's place in the universe. The Illustris project exhausted 20 million CPU hours in 2014 following 12 billion resolution elements spanning a cube 35 million light years on a side as it evolved over 13 billion years.The simulation tracks matter into the formation of a wide variety of galaxy types.As the virtual universe evolves, some of the matter expanding with the universe soon gravitationally condenses to form filaments, galaxies, and clusters of galaxies.The featured video takes the perspective of a virtual camera circling part of this changing universe, first showing the evolution of dark matter, then hydrogen gas coded by temperature (0:45), then heavy elements such as helium and carbon (1:30), and then back to dark matter (2:07).On the lower left the time since the Big Bang is listed, while on the lower right the type of matter being shown is listed. Explosions (0:50) depict galaxy-center supermassive black holes expelling bubbles of hot gas.Interesting discrepancies between Illustris and the real universe have been studied, including why the simulation produced an overabundance of old stars.

2023年12月26日:IC 443：水母星云-（IC 443: The Jellyfish Nebula） 2023年12月26日:IC 443：水母星云-（IC 443: The Jellyfish Nebula）--原图下载{mtitle title="IC 443：水母星云"/}Image Credit & Copyright: David Payne说明: 为何会有水母悠游在恒星海里？影像中漂浮在亮星銊（右侧）附近的水母星云，其触手往中左方的弧形亮脊方向伸展。水母星云其实是气泡状超新星遗迹IC 443的一部份，是一颗大质量恒星爆炸后所留下的扩张碎片云。来自这个超新星爆炸的亮闪，大约在30,000年前首次传到地球。就像它在天文海洋里的同类--超新星遗迹蟹状星云一样，IC 443之内也藏着一颗星核崩塌后形成的中子星。水母星云离我们约5,000光年远。以此距离来换算，这张主题影像的跨幅约为140光年。（Jellyfish Nebula 水母星云; Eta Gem 銊）{lamp/}原文：{mtitle title="IC 443: The Jellyfish Nebula"/}Image Credit & Copyright: David PayneExplanation: Why is this jellyfish swimming in a sea of stars?Drifting near bright star Eta Geminorum, seen at the right, the Jellyfish Nebula extends its tentacles from the bright arcing ridge of emission left of center. In fact, the cosmic jellyfish is part of bubble-shaped supernova remnant IC 443, the expanding debris cloud from a massive star that exploded. Light from the explosion first reached planet Earth over 30,000 years ago. Like its cousin in astronomical waters, the Crab Nebula supernova remnant IC 443 is known to harbor a neutron star -- the remnant of the collapsed stellar core. The Jellyfish Nebula is about 5,000 light-years away. At that distance, the featured image would span about 140 light-years across.

2023年12月06日:船底座的恆星与尘埃之战-（Stars Versus Dust in the Carina Nebula） 2023年12月06日:船底座的恆星与尘埃之战-（Stars Versus Dust in the Carina Nebula）--原图下载{mtitle title="船底座的恆星与尘埃之战"/}Image Credit: NASA, ESA, Hubble Heritage (STScI/AURA); Processing: Franco Meconi (Terraza al Cosmos)说明: 船底大星云里，在恒星与尘埃的战争中，恒星佔了上风。更精确地说，是刚诞生的大质量恒星之高能星光和恒星风，逐渐把孕育它们的尘埃恒星育婴室蒸发及吹散掉。这些位在船底大星云内、暱称为神祕山的尘埃柱，绝大部分的成分是透明的氢气，但其外观却是受到不透光棕色尘埃的主宰。虽然其中的部分尘埃柱形似火把，但它们的顶端并没着火，只是受到邻近恒星的照耀。这幅由哈伯太空望远镜所拍摄的主题影像，突显了约7,500光年远的船底座星云内约1光年的区域。在数百万年之内，恒星很可能会完全胜出，而这些尘埃火把将会蒸发迨尽。{lamp/}原文：{mtitle title="Stars Versus Dust in the Carina Nebula"/}Image Credit: NASA, ESA, Hubble Heritage (STScI/AURA); Processing: Franco Meconi (Terraza al Cosmos)Explanation: It's stars versus dust in the Carina Nebula and the stars are winning.More precisely, the energetic light and winds from massive newly formed stars are evaporating and dispersing the dusty stellar nurseries in which they formed.Located in the Carina Nebula and inside a region known informally as Mystic Mountain, these pillars' appearance is dominated by opaque brown dust even though it is composed mostly of clear hydrogen gas.Even though some of the dust pillars look like torches, their ends are not on fire -- rather, they are illuminated by nearby stars. About 7,500 light-years distant, the featured image was taken with the Hubble Space Telescope and highlights an interior region of Carina known as HH1066 which spans nearly a light year.Within a few million years, the stars will likely win out completely and the dust torches will completely evaporate.

2023年11月08日:欧几里得太空望远镜的英仙星系团-（Perseus Galaxy Cluster from Euclid） 2023年11月08日:欧几里得太空望远镜的英仙星系团-（Perseus Galaxy Cluster from Euclid）--原图下载{mtitle title="欧几里得太空望远镜的英仙星系团"/}Image Credit & License: ESA, Euclid, Euclid Consortium, NASA;Processing: Jean-Charles Cuillandre (CEA Paris-Saclay) & Giovanni Anselmi;Text: Jean-Charles Cuillandre说明: 天空新增了一部名为欧几里得（Euclid）的太空望远镜。欧几里得配备了两部大型的全景相机，用以捕捉从可见光到近红外光的讯息。拥有直径1.2米主镜的欧几里得望远镜，通过锐利的光学系统进行5个小时的持续观测，才拍下了这幅呈现2.5亿光年外英仙星系团里的1,000多个星系之影像。此外，这张影像还记录了10多万个背景星系，有些甚至远在100亿光年之外。欧几里得望远镜的创新性，在于它超过2倍满月面积的宽视场、其6.2亿像素相机所带来的高角度解析率、以及它的红外光视力，更难得的是能同时取得影像和光谱资讯。欧几里得望远镜初步计划要勘测3分之1的天空，并记录超过20亿个星系，以进行暗物质和暗能量是如何塑造我们宇宙的研究。{lamp/}原文：{mtitle title="Perseus Galaxy Cluster from Euclid"/}Image Credit & License: ESA, Euclid, Euclid Consortium, NASA;Processing: Jean-Charles Cuillandre (CEA Paris-Saclay) & Giovanni Anselmi;Text: Jean-Charles CuillandreExplanation: There's a new space telescope in the sky: Euclid.Equipped with two large panoramic cameras, Euclid captures light from the visible to the near-infrared. It took five hours of observing for Euclid's 1.2-meter diameter primary mirror to capture, through its sharp optics, the 1000+ galaxies in the Perseus cluster, which lies 250 million light years away. More than 100,000 galaxies are visible in the background, some as far away as 10 billion light years.The revolutionary nature of Euclid lies in the combination of its widefield of view (twice the area of the full moon), its high angular resolution(thanks to its 620 Megapixel camera), and its infrared vision, which captures both images and spectra. Euclid's initial surveys, covering a third of the sky and recording over 2 billion galaxies, will enable a study of how dark matter and dark energy have shaped our universe.

2023年10月30日:鬼魂星魂-（Reflections of the Ghost Nebula） 2023年10月30日:鬼魂星魂-（Reflections of the Ghost Nebula）--原图下载{mtitle title="鬼魂星魂"/}Image Credit & Copyright: Bogdan Jarzyna说明: 在这片恒星和尘埃里，有没有天体马上抓住你的目光？这些广袤、宝石般、内有不停反射暗淡星光云气的星云，漂流在仙王座方向的夜空中。 这些座落在地球外头约1,200光年远处的星云，位于银河盘面的仙王火焰分子云複合体的边缘。在这张主题影像底部，长超过2光年，比其他幽灵状云气要明亮的的怪物般云气，则是VdB 141（亦称Sh2-136、鬼魂星云或幽云星云）。 在这团反射星云里的緻密云核，已展现出处在恒星形成阶段的早期、正在发生塌缩的诸多特徵迹证。{lamp/}原文：{mtitle title="Reflections of the Ghost Nebula"/}Image Credit & Copyright: Bogdan JarzynaExplanation: Do any shapes seem to jump out at you from this interstellar field of stars and dust? The jeweled expanse, filled with faint, starlight-reflectingclouds, drifts through the night in the royal constellation of Cepheus.Far from your own neighborhood on planet Earth, these ghostly apparitions lurk along theplane of the Milky Way at theedge of the Cepheus Flaremolecular cloud complex some 1,200 light-years away.Over two light-years across and brighter than the other spooky chimeras, VdB 141 or Sh2-136 is also known as theGhost Nebula, seen toward the bottom of the featured image.Within the reflection nebula are the telltale signs of dense corescollapsingin the earlystages of star formation.