2024年08月27日:月掩土星-（Moon Eclipses Saturn） 2024年08月27日:月掩土星-（Moon Eclipses Saturn）--原图下载{mtitle title="月掩土星"/}Image Credit & Copyright: Pau Montplet Sanz说明: 土星会不会突然消失？有时还真的会。不过，它并不是真的消失了，只是我们的月球通过它的前方，让它消失在我们的视线里。这样的土星食，正式的名称是掩星，而就在几天前，从秘鲁横过大西洋到义大利的地球长条区域，都见到了这个月掩土星事件。这张彩色的主题影像，数位融合了数张记录此事件的最清晰照片，并针对相对昏暗的土星和相对明亮的月球，进行了色彩和亮度的调整。这些呈现掩星即将发生前景观的照片，都是摄于西班牙的布瑞达村。今年接下来到年底的这些月份，都会发生月掩土星。只不过，这些稍纵即逝的事件，只有位于地球适当地点和有清朗天空的人们才得见。{lamp/}原文：{mtitle title="Moon Eclipses Saturn"/}Image Credit & Copyright: Pau Montplet SanzExplanation: What if Saturn disappeared? Sometimes, it does. It doesn't really go away, though, it just disappears from view when our Moon moves in front. Such a Saturnian eclipse, more formally called an occultation, was visible along a long swath of Earth -- from Peru, across the Atlantic Ocean, to Italy -- only a few days ago. The featured color image is a digital fusion of the clearest images captured during the event and rebalanced for color and relative brightness betweenthe relatively dim Saturn and the comparatively bright Moon.Saturn and the comparative bright Moon. The exposures were all taken from Breda, Catalonia, Spain, just before occultation.Eclipses of Saturn by our Moon will occur each month for the rest of this year.Each time, though, the fleeting event will be visible only to those with clear skies -- and the rightlocation on Earth.

2024年08月25日:土卫二表面的鲜明虎纹-（Fresh Tiger Stripes on Saturn's Enceladus） 2024年08月25日:土卫二表面的鲜明虎纹-（Fresh Tiger Stripes on Saturn's Enceladus）--原图下载{mtitle title="土卫二表面的鲜明虎纹"/}Image Credit: NASA,ESA,JPL,SSI,Cassini Imaging Team说明: 土卫二（Enceladus）的地下海洋，是否透过裂谷向外排气？土卫二暱称为"虎纹"的长条表面结构，证实会朝太空喷发这颗冰冻卫星内部的冰，形成笼罩在南极上空的冰晶云，并造就了土星神祕的E环。 支持的证据来自在2004年到2017年间，绕行土星系统的卡西尼号探测船。这幅高解析的土卫二影像，即是在一次近距离飞越时所拍摄，而其中不寻常的表面虎纹结构，是用泛蓝的假色来呈现。不过，为何土卫二会如此活跃，则仍然是个谜，因为附近和土卫二大小相近的土卫一，是个死寂的卫星。经由分析喷出的冰粒 ，后来更找到了土卫二内部有複杂含碳有机分子的证据。然而，这些富含碳的大分子，支持但无法证明土卫二地下海洋可能有生命。{lamp/}原文：{mtitle title="Fresh Tiger Stripes on Saturn's Enceladus"/}Image Credit: NASA,ESA,JPL,SSI,Cassini Imaging TeamExplanation: Do underground oceans vent through canyons on Saturn's moon Enceladus? Long features dubbed tiger stripes are known to bespewing ice from the moon's icy interior into space,creating a cloud of fine ice particles over the moon's South Poleand creating Saturn's mysterious E-ring. Evidence for this has come from therobot Cassini spacecraft that orbited Saturn from 2004 to 2017. Pictured here,a high resolution image of Enceladus is shown from a close flyby. The unusual surface features dubbedtiger stripes are visible in false-color blue. WhyEnceladus is active remains a mystery, as the neighboring moonMimas, approximately the same size, appearsquite dead.An analysis of ejected ice grains has yielded evidence that complex organic molecules exist inside Enceladus.These large carbon-rich molecules bolster -- but do not prove -- that oceans under Enceladus' surface could contain life.

2024年01月15日:韦伯影像：星团IC 348-（Star Cluster IC 348 from Webb） 2024年01月15日:韦伯影像：星团IC 348-（Star Cluster IC 348 from Webb）--原图下载{mtitle title="韦伯影像：星团IC 348"/}Image Credit: NASA, ESA, CSA, STScI, and K. Luhman (Penn State U.) and C. Alves de Oliveira (ESA)说明: 有时候，最难见到的恒星才最有趣。年轻的星团IC 348，照亮了周围的细丝状尘埃。在韦伯太空望远镜最近发布的这张红外光影像里，这些捲曲细丝状尘埃带着粉红的色泽。在可见光波段，这些尘埃以反射蓝光为主，因此星团周围的物质，会带着反射星云熟悉的泛蓝色调。除了明亮的恒星之外，在IC 348 里还找到数个低温天体，这些天体之所以可见，则是它们在红外光波段很明亮。假说认为这些天体可能是小质量的棕矮星。支持这种说法的证据，包括侦测到一种不明的大气化学物质，而它很可能是先前发现于土星 大气中的碳氢化合物。这些天体的质量似乎略大于已知的行星，仅是木星的数倍之多。总之，迹证显示这个年轻星团拥有值得关注的天体，特别是指质量和行星相近、自由漂浮并未绕行任何恒星的棕矮星。{lamp/}原文：{mtitle title="Star Cluster IC 348 from Webb"/}Image Credit: NASA, ESA, CSA, STScI, and K. Luhman (Penn State U.) and C. Alves de Oliveira (ESA)Explanation: Sometimes, it's the stars that are the hardest to see that are the most interesting.IC 348 is a young star cluster that illuminates surrounding filamentary dust. The stringy and winding dust appears pink in this recently released infrared image from the Webb Space Telescope.In visible light, this dust reflects mostly blue light, giving the surrounding material the familiar blue hue of a reflection nebula. Besides bright stars, several cool objects have been located in IC 348, visible because they glow brighter in infrared light. These objects are hypothesized to be low mass brown dwarfs. Evidence for this includes the detection of an unidentified atmospheric chemical, likely a hydrocarbon, seen previously in the atmosphere of Saturn.These objects appear to have masses slightly greater than known planets, only a few times greater than Jupiter. Together, these indicate that this young star cluster contains something noteworthy -- young planet-mass brown dwarfs that float free, not orbiting any other star.

2023年08月25日:土星的一季-（A Season of Saturn） 2023年08月25日:土星的一季-（A Season of Saturn）--原图下载{mtitle title="土星的一季"/}Image Credit &Copyright: Andy Casely说明: 2023年8月27日，拥有行星环的土星将发生土星冲，于地球天空中与太阳180度反向。届时，这颗离太阳第六远的行星，将处在最明亮、非常适合观测的位置，不过肉眼并无法见到它美丽的环系。然而，这组摄于过去6年期间、每年拍摄一祯的望远镜影像系列，清楚呈现了在内行星地球所见到的土星和土星环。在影像里，这颗气态巨行星的行星环面，从2018年的最正向倾侧转变成2023年的接近侧向（从上到下）。对土星的北半球来说，季节也在这段期间从夏季来到了土星的秋分附近。在这幅清晰的行星影像里，于2018年之时，土星的北极六角云与大风暴系统清楚可辨。于2023年，冰卫星土卫三（Tethys）正在淩越土星，并把影子投射在南半球的云带上，而土星冰寒泛蓝的南极，也正从将近10年的冬季永夜中冒出头来。{lamp/}原文：{mtitle title="A Season of Saturn"/}Image Credit &Copyright: Andy CaselyExplanation: Ringed planet Saturnwill be at its 2023 opposition,opposite the Sun in Earth's skies, on August 27.While that puts the sixth planet from the Sun at itsbrightest and well-placedfor viewing, its beautiful ring system isn'tvisible to the unaided eye.Still, this sequence of six telescopic images taken a year apartfollows both Saturn and rings as seen from inner planet Earth.The gas giant's ring plane tiltsfrom most open in 2018 to approaching edge-on in 2023 (top to bottom).That's summer to nearly the autumnequinox for Saturn's northern hemisphere.In the sharp planetary portraits Saturn's northernhexagon and a largestorm system are clearly visible in 2018.In 2023 ice moon Tethysis transiting, casting its shadow acrosssouthern hemisphere cloud bands whileSaturn's cold blue south pole is emergingfrom almost a decade of winter darkness.

2023年06月25日:木星的闪电-（Lightning on Jupiter） 2023年06月25日:木星的闪电-（Lightning on Jupiter）--原图下载{mtitle title="木星的闪电"/}Image Credit: NASA/JPL-Caltech/SwRI/MSSS;Processing & License:Kevin M. Gill说明: 地球是唯一有闪电的行星吗？不是。探索太阳系的多艘太空船，已在火星、木星及土星等行星侦测到闪电，此外，金星、天王星及海王星可能也有闪电。闪电是带电粒子在二个区域之间急遽流动所产生的现象。在地球上，一波波有互撞冰粒及小水滴的涌升流，通常是造成电荷分离进而产生闪电的关键，然而，木星的闪电是怎么来的？绕行木星的朱诺号太空船的所取得的影像和数据，进一步支持木星的闪电亦是由含水及冰的云所产生的之揣测。在这幅由朱诺号所拍摄的主题照片里，可看到出现在木星北极大涡旋云的光学亮闪。在接下来的数个月里，朱诺号将进行数次木星夜面的近距离飞越，届时朱诺号或许可取得更多木星的闪电数据与影像。{lamp/}原文：{mtitle title="Lightning on Jupiter"/}Image Credit: NASA/JPL-Caltech/SwRI/MSSS;Processing & License:Kevin M. GillExplanation: Does lightning occur only on Earth? No. Spacecraft in our Solar System have detected lightning on other planets, including Mars, Jupiter and Saturn, and lightning is likely on Venus,Uranus, and Neptune. Lightning is a sudden rush of electrically charged particles from one location to another.On Earth, drafts of colliding ice and water droplets usually create lightning-generating charge separation, but what happens on Jupiter?Images and data from NASA's Jupiter-orbiting Juno spacecraft bolster previous speculation that Jovian lightning is also created in clouds containing water and ice. In the featured Juno photograph, an optical flash was captured in a large cloud vortex near Jupiter's north pole. During the next few months, Juno will perform several close sweeps over Jupiter's night side, likely allowing the robotic probe to capture more data and images of Jovian lightning.

2023年04月02日:哈伯影像：环状星云M57-（M57: The Ring Nebula from Hubble） 2023年04月02日:哈伯影像：环状星云M57-（M57: The Ring Nebula from Hubble）--原图下载{mtitle title="哈伯影像：环状星云M57"/}Image Credit: NASA, ESA, Hubble Legacy Archive; Processing: Judy Schmidt说明: 早在数百年前观星者就已注意到它，但他们无法理解其不寻常的形状。除了土星环之外，环状星云（M57）可能是最着名的环状天体。不过它经典的形状，我们如今了解其实是源自地球的特殊视角。最近根据这张极清晰的哈伯影像，为这不停扩张的星云所建构的三维结构显示，这团星云的结构是一个相对緻密的甜甜圈，围拱着中央形似美式足球的明亮云气。从我们所在的地球看出去，视线正好顺着足球的长轴，直视星云环的正面。当然，这团已被大量研究的行星状星云之发光物质，并非来自行星。而是来自类太阳恒星在死亡的过程中所抛出的外壳，而星云中心的针尖状光点，则是这颗恒星的孑遗。这颗炽热的中心星，发出强烈的紫外光电离云气的原子并激发它们发光。距离我们约2,500光年的环状星云，宽度约有1光年。{lamp/}原文：{mtitle title="M57: The Ring Nebula from Hubble"/}Image Credit: NASA, ESA, Hubble Legacy Archive; Processing: Judy SchmidtExplanation: It was noticed hundreds of years ago by stargazers who could not understand its unusual shape. It looked like a ring on the sky.Except for the ringsof Saturn, the RingNebula (M57) may be the most famous celestial circle.We now know what it is, and that its iconic shape isdue to our lucky perspective.The recent mapping of theexpanding nebula's3-D structure, based in part onthis clear Hubble image,indicates thatthe nebula is a relatively dense, donut-like ring wrappedaround the middle of an (American) football-shaped cloud of glowing gas.Our view from planet Earth looks down the long axis of the football,face-on to the ring.Of course, in this well-studied example of aplanetary nebula, the glowing materialdoes not come from planets.Instead, the gaseous shroud represents outer layers expelledfrom the dying,oncesun-like star, now a tiny pinprick of lightseen at the nebula's center.Intense ultraviolet light from the hot central starionizes atoms in the gas.The Ring Nebula is about one light-yearacross and 2,500 light-years away.