木星湍动的云

木星湍动的云

2020年8月11日 Churning Clouds on Jupiter Image Credit & License: NASA/JPL-Caltech/SwRI/MSSS; Processing: Kevin M. Gill Explanation: Where is Jupiter’s ammonia? Gaseous ammonia was expected to be seen in Jupiter’s upper atmosphere by the orbiting Juno spacecraft — but in many clouds is almost absent. Recent Juno data, however, gives some clues: some high-level clouds appear to be home to an unexpected type of electrical discharge dubbed shallow lightning. Great charge separations are needed for lightning, which might be created by colliding mushballs lifted by rising updrafts of gas. Ammonia and water stick to these mushballs which rise until they get too heavy — after which they fall deep into Jupiter’s atmosphere and melt. By this process, ammonia found missing from Jupiter’s upper atmosphere reappears below. Pictured…

夏季天空中的巨行星

夏季天空中的巨行星

2020年7月29日 The Giants of Summer Image Credit & Copyright: Jean-Luc Dauvergne Explanation: As Comet NEOWISE sweeps through northern summer skies, Jupiter and Saturn are shining brightly, near opposition. With Jupiter opposite the Sun on July 14 and Saturn on July 21, the giant planets are still near their closest to planet Earth in 2020. Sharing the constellation Sagittarius they are up all night, and offer their best and brightest views at the telescope. Both captured on July 22 from a balcony in Paris these two sharp telescopic images don’t disappoint, showing off what the giant planets are famous for, Saturn’s bright rings and Jupiter’s Great Red Spot. These giants of the Solar System are worth following during 2020. On December 21, skygazers can watch the…

木星壮丽的漩涡云

木星壮丽的漩涡云

A multitude of magnificent, swirling clouds in Jupiter’s dynamic North North Temperate Belt is captured in this image from NASA’s Juno spacecraft. Appearing in the scene are several bright-white “pop-up” clouds as well as an anticyclonic storm, known as a white oval. This color-enhanced image was taken at 4:58 p.m. EDT on Oct. 29, 2018 as the spacecraft performed its 16th close flyby of Jupiter. At the time, Juno was about 4,400 miles from the planet’s cloud tops, at a latitude of approximately 40 degrees north. Citizen scientists Gerald Eichstädt and Seán Doran created this image using data from the spacecraft’s JunoCam imager. JunoCam’s raw images are available at www.missionjuno.swri.edu/junocam for the public to peruse and process into image products. Image Credit: Enhanced Image by…

银河系、行星与苹果树

银河系、行星与苹果树

2020 July 2 The Galaxy, the Planet, and the Apple Tree Image Credit & Copyright: Kristine Richer Explanation: The Old Astronomer’s Milky Way arcs through this peaceful northern sky. Against faint, diffuse starlight you can follow dark rifts of interstellar dust clouds stretching from the galaxy’s core. They lead toward bright star Antares at the right, almost due south above the horizon. The brightest beacon in the twilight is Jupiter, though. From the camera’s perspective it seems to hang from the limb of a tree framing the foreground, an apple tree of course. The serene maritime nightscape was recorded in tracked and untracked exposures on June 16 from Dover, Nova Scotia, planet Earth. Tomorrow’s picture: pixels in space 银河系、行星与苹果树 图像提供与版权:Kristine Richer 说明:在这幅宁静的北天影像里,老天文学家珍爱的银河斜贯而过。而在弥漫暗淡的星光衬托下,从银心伸出由星际尘埃云构成的裂谷亦历历可辨。这些裂谷看似伸向影像右侧,悬在南方地平线上空的亮星心宿二。不过,在这片曙光时分的天空中,最明亮的天体是木星。从这部相机看出去,它看似挂在前景苹果树的枝桠上。这幅静谧的海岸夜空影像,是由今年6月16日摄于地球·新斯科细亚省·多佛地区的多张导星与无导星照片组合而成。 明日的图片:pixels in space

旅行者1号拍摄的木卫二和木星

旅行者1号拍摄的木卫二和木星

2020 June 28 Europa and Jupiter from Voyager 1 Image Credit: NASA, Voyager 1, JPL, Caltech; Processing & License: Alexis Tranchandon / Solaris Explanation: What are those spots on Jupiter? Largest and furthest, just right of center, is the Great Red Spot — a huge storm system that has been raging on Jupiter possibly since Giovanni Cassini’s likely notation of it 355 years ago. It is not yet known why this Great Spot is red. The spot toward the lower left is one of Jupiter’s largest moons: Europa. Images from Voyager in 1979 bolster the modern hypothesis that Europa has an underground ocean and is therefore a good place to look for extraterrestrial life. But what about the dark spot on the upper right? That…

喜马拉雅雪峰上空的银河

喜马拉雅雪峰上空的银河

2020 May 26 The Milky Way over Snow-Capped Himalayas Image Credit & Copyright: Tomas Havel Explanation: What’s higher than the Himalayas? Although the Himalayan Mountains are the tallest on planet Earth, they don’t measure up to the Milky Way. Visible above the snow-capped mountains in the featured image is the arcing central band of our home galaxy. The bright spot just above the central plane is the planet Jupiter, while the brightest orange spot on the upper right is the star Antares. The astrophotographer braved below-zero temperatures at nearly 4,000-meters altitude to take the photographs that compose this image. The featured picture is a composite of eight exposures taken with same camera and from the same location over three hours, just after sunset, in 2019…

木星上的高空雾

木星上的高空雾

NASA’s Juno mission captured this look at Jupiter’s tumultuous northern regions during the spacecraft’s close approach to the planet on Feb. 17, 2020. Notable features in this view are the long, thin bands that run through the center of the image from top to bottom. Juno has observed these long streaks since its first close pass by Jupiter in 2016. The streaks are layers of haze particles that float above the underlying cloud features. Scientists don’t yet know exactly what these hazes are made of or how they form. Two jet streams in Jupiter’s atmosphere flank either side of the region where the narrow bands of haze typically appear, and some researchers speculate those jet streams may influence the formation of the high hazes. This…

双子望远镜拍摄的红外光木星影像

双子望远镜拍摄的红外光木星影像

2020 May 13 Jupiter in Infrared from Gemini Image Credit: International Gemini Observatory, NOIRLab, NSF, AURA; M. H. Wong (UC Berkeley) & Team; Acknowledgment: Mahdi Zamani; Text: Alex R. Howe (NASA/USRA, Reader’s History of SciFi Podcast) Explanation: In infrared, Jupiter lights up the night. Recently, astronomers at the Gemini North Observatory in Hawaii, USA, created some of the best infrared photos of Jupiter ever taken from Earth’s surface, pictured. Gemini was able to produce such a clear image using a technique called lucky imaging, by taking many images and combining only the clearest ones that, by chance, were taken when Earth’s atmosphere was the most calm. Jupiter’s jack-o’-lantern-like appearance is caused by the planet’s different layers of clouds. Infrared light can pass through clouds better…

伽利略号历史图片获得新生,展现了前所未有的木卫二“混沌地形”细节

伽利略号历史图片获得新生,展现了前所未有的木卫二“混沌地形”细节

这张图片是3幅新近处理过的木卫二图像的其中之一,在卫星冰冷的表面上,你能看到各种地质特征的细节。这张图片显示的区域被称为“混沌过渡”,上面有着已经移动过的物质块以及表面隆起,这可能与木星引力所引发的壳层破裂有关。 图片来源:NASA/喷气推进实验室-加州理工/地外文明探索研究所(Search for Extraterrestrial Intelligence Institute,SETI Institute) 木卫二(Europa)欧罗巴的表面上,满是各式各样的地质景观,包括隆起的脊、带状的路、圆形的小凸顶,以及被地质学家称为“混沌地形”(chaos terrain)的破碎形貌。1990年代后期美国航空航天局(NASA)伽利略号木星探测器(Galileo)所拍摄的3幅图像,近期进行了再次处理,揭示了木卫二表面上多种特征的细节。 虽然伽利略号拍摄的数据已经“芳龄”二十有余了,但随着图像处理技术的不断发展,科学家也一直在重新处理和解读这些历史图像,创建木卫二表面更细节更全面的新视图,为木卫二快船(Europa Clipper)的启程做准备。木卫二快船这一新的木星轨道飞行器将数十次飞越木卫二,目的是进一步了解这颗卫星厚实冰壳下方的海洋以及它与卫星表面的相互作用。木卫二快船任务计划在未来几年内发射,将是自伽利略号以来人类首次重返木卫二。 NASA喷气推进实验室(JetPropulsion Laboratory)的行星地质学家辛西娅·菲利普斯(Cynthia Phillips)表示:“在现有的分辨率下,我们只看到了很小一部分的木卫二表面。木卫二快船将会极大地增加我们能观测到的卫星表面。”喷气推进实验室从属于加州理工学院(California Institute of Technology,Caltech),作为木卫二项目的科学家,菲利普斯负责一项长期的研究项目,那就是重新分析木卫二的图像。 上面的地图显示了3张木卫二特征图像拍摄的位置信息,由北向南依次是“混沌过渡”(Chaos Transition)、“ 纵横带”(Crisscrossing Bands)和“阿格诺尔线附近混沌”(Chaos Near Agenor Linea),3张图像的中心分别大约位于北纬6.4度、南纬10.5度和南纬40.7度,经度均为东经135.3度。该图片拍摄于伽利略号的第8次木卫二定向飞越期间。 图片来源:NASA/喷气推进实验室-加州理工 1998年9月26日,伽利略号在它的第17木星轨道(E17轨道)上飞行时,沿着木卫二的同一经度拍摄了这三张照片,那是伽利略号总计11次木卫二定向飞越中的第8次。在清晰的灰度(黑白)滤镜下,伽利略号拍摄的高分辨率图像能显现出尺寸小至500码(460米)的表面特征,利用其他飞越(E14轨道上的飞越)所拍摄的相同区域低分辨率彩色图像,技术人员给原本只有黑白灰的高分辨率图像进行了上色,黑白到彩色的转变是一个非常耗费心力的过程。 应用不同的颜色,科学家可以在经过处理的彩色增强图像上突出显示不同的地质特征,这种图像所展现的木卫二不是人眼会看到的样子,而是夸大了颜色变化从而突出显示卫星表面的不同化学成分。呈现出淡蓝色或白色的区域,组成成分为相对纯净的水冰,而略带红色的区域则含有更多的非冰物质,例如盐。 对木卫二的高分辨率图像进行研究,行星科学家可以获取卫星表面形成方式的相关线索。我们如今所看到的木卫二表面平均只有4000万年到9000万年的历史,比46亿年前伴随太阳系形成而诞生的木卫二本身要年轻得多。实际上,木卫二拥有着我们太阳系中最年轻的表面之一,这也是它众多奇特的异处之一。 这张图片显示了名为“纵横带”的区域,其中隆起的脊状形貌可能由表面裂缝反复打开和闭合所形成;而在裂缝继续沿水平方向拉伸张开时,则可能形成了宽大且相对平滑的带状形貌特征。 图片来源:NASA/喷气推进实验室-加州理工/地外文明探索研究所 木卫二表面纵横交错着长线形的隆起和带状结构,可能与木星的引力作用相关:木星强大的引力或许拉伸和拽动着卫星表面的冰冻壳层,从而形成了这样奇绝的表面特征。山脊般的隆起可能源于表面裂缝反反复复的打开和闭合,这种壳层运动形成了几百米高、几千米宽、可水平跨越数千公里的地质形貌。 与之相反的是带状结构,它似乎是由裂缝在水平方向上继续拉开而产生的较为宽阔且相对平坦的形貌特征。 这张图片显示了木卫二的“混沌地形”,区域中的物质块已经经过了移动、旋转、倾斜和重新冰冻。面对这一地质谜团,科学家正努力寻找木卫二表面演化方式的线索。图中所示的区域被称为“阿格诺尔线附近混沌”,因为它靠近图像底部名为阿格诺尔线(Agenor Linea)的带状特征。 图片来源:NASA/喷气推进实验室-加州理工/地外文明探索研究所 所谓的混沌地形区域包含了较大的块状物质,它们经历过侧向移动、旋转或倾斜之后到达了我们所看到的新位置。为了研究这些物质块是如何形成的,科学家将它们看作散落在混沌地形中的拼图碎片。 伽利略号任务由喷气推进实验室为NASA位于华盛顿的科学任务理事会(Science Mission Directorate)负责管理。有关伽利略号及更多的相关发现,请访问伽利略号任务主页: https://solarsystem.nasa.gov/missions/galileo/overview/ 想了解木卫二和木卫二快船的更多信息,请访问: https://europa.nasa.gov/ 参考来源: https://www.nasa.gov/feature/jpl/newly-reprocessed-images-of-europa-show-chaos-terrain-in-crisp-detail

蒙特利尔清晨天空中的行星和月亮

蒙特利尔清晨天空中的行星和月亮

2020 March 20 Morning, Planets, Moon and Montreal Image Credit & Copyright: Arnaud Mariat Explanation: Dawn’s early light came to Montreal, northern planet Earth, on March 18, the day before the vernal equinox. At the end of that nearly equal night the Moon stands above a dense constellation of urban lights in this serene city and skyscape. Of course the Moon’s waning crescent faces toward the rising Sun. Skygazers could easily spot bright Jupiter just above the Moon, close on the sky to a fainter Mars. Saturn, a telescopic favorite, is just a pinprick of light below and farther left of the closer conjunction of Moon, Jupiter and Mars. Near the ecliptic, even Mercury is rising along a line extended to the horizon from Jupiter…