2024年08月18日:太阳动态观测卫星拍到的日珥爆发-（A Solar Prominence Eruption from SDO） 2024年08月18日:太阳动态观测卫星拍到的日珥爆发-（A Solar Prominence Eruption from SDO）--原图下载2024 August 18 {mtitle title="太阳动态观测卫星拍到的日珥爆发"/}Image Credit: NASA/Goddard/SDO AIA Team说明: 日珥爆发是太阳最壮观的景观之一。在2011年，美国航太总署的太阳动态观测卫星（SDO），拍下了一例令人印象深刻、发生于表面的庞大日珥爆发。于紫外光波段所记录的这例壮观爆发事件，成为了上面这部涵盖90分钟期间的缩时主题影片，其中每张定格拍摄的间隔为24秒。日珥是受到太阳磁场引导，有时会悬在太阳上空的一种结构。日珥极为庞大，在由流动炽热气体构成的帘状结构之下，可轻易地塞进整颗地球。此外，宁静的日珥通常可存续约一个月，最后可能会发生日冕物质抛射，将大量的炽热气体喷入太阳系。不过，日珥形成的能量机制目前仍然是研究的课题。太阳目前处在活动极大期附近，是以非常活跃，经常发生日珥爆发及日冕物质抛射，例如太阳刚在上星期发生一次爆发，并在地球诱发美丽的极光。{lamp/}原文：{mtitle title="A Solar Prominence Eruption from SDO"/}Image Credit: NASA/Goddard/SDO AIA TeamExplanation: One of the most spectacular solar sights is an erupting prominence.In 2011, NASA's Sun-orbitingSolar Dynamic Observatory spacecraft imaged animpressively large prominenceerupting from the surface.The dramatic explosion was captured in ultraviolet light in thefeatured 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 a continuing topic ofresearch. Our Sun is again near solar maximum and so very active, featuring numerous erupting prominences and CMEs, one of which resulted in picturesque auroras just over the past week.

2023年12月08日:织女星与彗星12P/庞士-布鲁克斯-（Vega and Comet 12P/Pons-Brooks） 2023年12月08日:织女星与彗星12P/庞士-布鲁克斯-（Vega and Comet 12P/Pons-Brooks）--原图下载{mtitle title="织女星与彗星12P/庞士-布鲁克斯"/}Image Credit &Copyright:Dan Bartlett说明: 在今年的12月4日，週期彗星12P/庞士-布鲁克斯与天琴座的最亮星织女分享了这片望远镜视野。距离地球约25光年的织女，是地球夜空的第五亮星，而这颗远为昏暗的彗星，距离地球约21光分。不过在最近的这几个月，爆发导致庞士-布鲁克斯的亮度急剧增加。因其长角的外观，这颗彗星有魔鬼彗星的暱称，不过，星际飞航的粉丝们则会认为这颗拥有扭曲大彗发的彗星，其实形似千年鹰号。哈雷型彗星12P/Pons-Brooks，上次造访太阳系内围是在1954年。它在2024年4月21日，将再次通过近日点这个最接近太阳的位置，这个时间点紧在日全食路径于4月8日穿过北美洲后的2星期。不过，由于它相对于太阳系黄道面的高倾角，週期彗星12P/Pons-Brooks的轨道永远不会和地球的轨道交错。（Comet 12P/Pons-Brooks 彗星12P/庞士-布鲁克斯； Millenium Falcon 千年鹰号）{lamp/}原文：{mtitle title="Vega and Comet 12P/Pons-Brooks"/}Image Credit &Copyright:Dan BartlettExplanation: On December 4, periodicComet 12P/Pons-Brooksshared thistelescopic field of viewwith Vega, alpha star of the northern constellation Lyra.Fifth brightest star in planet Earth's night,Vega is some 25light-years distant whilethe much fainter comet was about 21 light-minutes away.In recent months,outbursts have caused dramatic increasesin brightness for Pons-Brooks though.Nicknamed the Devil Comet for its hornlike appearance,fans of interstellar spaceflight have also suggestedthe distorted shape of this large comet's central coma looks like theMillenium Falcon.A Halley-type comet, 12P/Pons-Brookslast visited the innerSolar System in 1954.Its next perihelion passage or closest approach to the Sunwill be April 21, 2024.That's just two weeks after the April 8 totalsolar eclipse path crosses North America.But, highly inclined to the Solar System's ecliptic plane,the orbit of periodicComet 12P/Pons-Brookswill never cross the orbit of planet Earth.

2023年10月12日:造父四-（Mu Cephei） 2023年10月12日:造父四-（Mu Cephei）--原图下载{mtitle title="造父四"/}Image Credit &Copyright:David Cruz说明: 造父四是一颗很庞大的恒星。它的分类为M型的超巨星，直径约莫是太阳的1,500倍，是肉眼可见的最大恒星之一，甚至是整个银河系最庞大的恒星之一。如果用它来取代太阳系的太阳，那么造父四可轻易吞没火星和木星。造父四的色泽极红，在历史上有赫歇尔的石榴石星之称。这颗超巨星的温度远比太阳低，本来就比太阳红，更由于银河系居间的尘埃之吸收和散射作用，因此它的星光受到进一步红化。在这片远眺北天仙王座方向的望远镜视野里，这颗距离我们约2800光年的超巨星，紧邻着泛红的发射星云IC 1396。这颗备受研究、咸信处于恒星演化末期的大质量变星，最终注定会以星核塌缩超新星的形式发生爆炸。（Mu Cephei 造父四）{lamp/}原文：{mtitle title="Mu Cephei"/}Image Credit &Copyright:David CruzExplanation: Mu Cepheiis a very large star.An M-class supergiant some 1500 times the size of the Sun, it is one ofthe largest stars visible to the unaided eye,and even one of the largest in the entire Galaxy.If it replaced the Sun inour fair Solar System,Mu Cephei would easily engulf Mars and Jupiter.Historically known asHerschel's Garnet Star,Mu Cephei is extremely red.Approximately 2800 light-years distant, the supergiant isseen near the edge of reddish emission nebulaIC 1396 towardthe royal northern constellation Cepheus inthis telescopic view.Much cooler and hence redder than the Sun,this supergiant's light is further reddened by absorption andscattering due to intervening dust within the Milky Way.A well-studied variable starunderstood to be in a late phaseof stellar evolution, Mu Cephei is a massive star too,destinedto ultimately explode as a core-collapsesupernova.

2023年07月31日:火星上空的火卫一-（Phobos over Mars） 2023年07月31日:火星上空的火卫一-（Phobos over Mars）--原图下载{mtitle title="火星上空的火卫一"/}Image Credit: ESA, DLR, FU Berlin, Mars Express;Processing & CC BY 2.0 License:Andrea Luck说明: 火卫一为何如此黝黑？火卫一是火星的两颗卫星之中，最大和最接近火星的那颗，同时也是整个太阳系里最黝黑的卫星。它不寻常的轨道与色泽，显示火卫一可能是被火星所俘获、组成混杂了冰晶与黑色石头的小行星。这幅火卫一悬在火星临边附近的人为上色主题影像，是由目前在绕行火星的欧洲航天局．火星特快车号摄于2021年。火卫一是颗荒芜满布陨石坑的卫星，它最大的撞击坑位于反面。分析包括此图在内的这类影像，科学家推断火卫一表面可能有一层厚达1公尺的粉尘。由于火卫一的轨道极为靠近火星，因此部分地区一天能看到火卫一发生二次升落，也有部分地区则是一次也没见到。火卫一的轨道不停衰减，大约在5千万年内，就会崩解并撞到火星表面上。{lamp/}原文：{mtitle title="Phobos over Mars"/}Image Credit: ESA, DLR, FU Berlin, Mars Express;Processing & CC BY 2.0 License:Andrea LuckExplanation: Why is Phobos so dark? Phobos, the largest and innermost of the twoMartian moons, is the darkest moon in the entire Solar System. Its unusual orbit and color indicate that it may be a captured asteroid composed of a mixture of ice and dark rock. The featured assigned-color picture of Phobos near the edge of Mars was captured in late 2021 by ESA's robot spacecraft Mars Express, currently orbiting Mars. Phobos is a heavily cratered and barren moon, with its largest crater located on the far side. From images like this, Phobos has been determined to be covered by perhaps a meter of loose dust. Phobos orbits so close to Mars that from some places it would appear to rise and set twice a day, while from other places it would not be visible at all. Phobos' orbit around Mars is continually decaying -- it will likely break up with pieces crashing to the Martian surface in about 50 million years.

2023年07月03日:破晓号的紫外金星-（Venus in Ultraviolet from Akatsuki） 2023年07月03日:破晓号的紫外金星-（Venus in Ultraviolet from Akatsuki）--原图下载{mtitle title="破晓号的紫外金星"/}Image Credit & Copyright: JAXA, Planet-C Project Team;h/t: Mehmet Hakan Özsaraç说明: 为什么金星和地球有这么大的差异呢？为找出答案提供助力，日本发射无人驾驶的破晓号太空船，并在历经5年规画外的内太阳系漫游之后，于2015年底入轨金星。纵然破晓号已经超出原订的任务期，但是太空船本体和仪器的功能仍运作如常，是以大部分的原始任务也重新启动。亦名为金星气候轨道船的破晓号，所搭载的仪器是要探索这颗地球姐妹行星的诸多未知，包括它的火山是否仍活跃，它的緻密大气是否有闪电活动，以及为何金星的大气风速远超出它的自转速率。在这幅由破晓号紫外相机所拍摄的主题影像里，金星的白昼面有个V形的行星尺度云系。这幅影像呈现了3个紫外波段的数据，其中的淡蓝区，为二氧化硫相对浓度较低的区域。在经由分析破晓号的影像和数据所获得的众多发现之中，包括证实金星也有类似地球喷射气流的赤道喷流。（Akatsuki spacecraft 破晓号太空船）{lamp/}原文：{mtitle title="Venus in Ultraviolet from Akatsuki"/}Image Credit & Copyright: JAXA, Planet-C Project Team;h/t: Mehmet Hakan ÖzsaraçExplanation: Why is Venus so different from Earth? To help find out, Japan launched the robotic Akatsuki spacecraft which entered orbit around Venus late in 2015 after an unplanned five-year adventure around the inner Solar System. Even though Akatsuki was past its original planned lifetime,the spacecraft and instruments were operatingso well that much of its original mission wasreinstated.Also known as the VenusClimate Orbiter, Akatsuki'sinstrumentsinvestigated unknowns about Earth's sister planet, including whether volcanoes are still active, whether lightning occurs in the dense atmosphere, and why wind speeds greatly exceed the planet's rotation speed.In the featured image taken by Akatsuki'sUVI camera, the day-side of Venus is seen shown with planet-scale V-shaped cloud pattern.The image displays three ultraviolet colors and indicates a dip in the relative abundance of sulfur dioxide shown in faint blue. Analyses of Akatsuki images and data has shown, among other discoveries, that Venus has equatorial jet similar to Earth's jet stream.

2023年06月18日:土星的北极六角云-（Saturn's Northern Hexagon） 2023年06月18日:土星的北极六角云-（Saturn's Northern Hexagon）--原图下载{mtitle title="土星的北极六角云"/}Image Credit & Copyright: NASA,ESA,JPL,SSI,Cassini Imaging Team说明: 为何土星的云会形如六角？ 目前没人知道其成因。它是首次发现于1980年代航行者号掠过土星之时，在那之前，太阳系内从来没见过这样的云系。后来在2012年底，卡西尼号太空船的广视角相机在土星日曜的北极区，拍下了这幅土星极区的扣人心弦假色影像。在这张由近红光数据组合成的影像里，以红色标示低层云，绿色标示高层层，让土星的云景变得格外鲜活。这幅及其他的影像，证实自航行者号发现后，这个六角云已稳定存在了20年以上。土星北极区的影片也证实，这种云在迴旋时仍然维持六角结构。此外，和地球上的六角云不同，土星的这种云系有6个等长的鲜明边界，而且六角形之内可容纳4个地球。在右上方的云顶后方，可见到渲染成亮蓝色的吸睛 土星环弧。{lamp/}原文：{mtitle title="Saturn's Northern Hexagon"/}Image Credit & Copyright: NASA,ESA,JPL,SSI,Cassini Imaging TeamExplanation: Why would clouds form a hexagon on Saturn?Nobody is sure. Originally discovered during the Voyager flybys of Saturn in the 1980s, nobody has ever seen anything like it anywhere else in the Solar System. Acquiring its first sunlit views of far northernSaturn in late 2012, theCassini spacecraft's wide-angle camera recorded thisstunning,false-color image of the ringed planet's north pole.The composite of near-infrared image dataresults in red hues for low clouds and green for high ones, giving theSaturnian cloudscape a vivid appearance.This and similar images show the stability of the hexagon even 20+ years after Voyager. Movies of Saturn's North Pole show the cloud structure maintaining its hexagonal structure while rotating. Unlike individual clouds appearing like a hexagon on Earth, the Saturn cloud pattern appears to have six well defined sides of nearly equal length.Four Earths could fit inside the hexagon.Beyond the cloud tops at the upper right, arcs of the planet'seye-catching rings are tinted bright blue.