被土星反照光照亮的土卫二

被土星反照光照亮的土卫二

ByNASA中文

2023年2月5日 Enceladus by Saturnshine Image Credit: NASA; ESA, JPL, Cassini Imaging Team, SSI; Color Composite: Gordan Ugarkovic Explanation: This moon is shining by the light of its planet. Specifically, a large portion of Enceladus pictured here is illuminated primarily by sunlight first reflected from the planet Saturn. The result is that the normally snow-white moon appears in the gold color of Saturn’s cloud tops. As most of the illumination comes from the image left, a labyrinth of ridges throws notable shadows just to the right of the image center, while the kilometer-deep canyon Labtayt Sulci is visible just below. The bright thin crescent on the far right is the only part of Enceladus directly lit by the Sun. The featured image was taken in 2011…

卡西尼号从土星往外看

卡西尼号从土星往外看

ByNASA中文

2022年12月23日 Cassini Looks Out from Saturn Image Credit: NASA, JPL-Caltech, Space Science Institute Explanation: This is what Saturn looks like from inside the rings. In 2017, for the first time, NASA directed the Cassini spacecraft to swoop between Saturn and its rings. During the dive, the robotic spacecraft took hundreds of images showing unprecedented detail for structures in Saturn’s atmosphere. Looking back out, however, the spacecraft was also able to capture impressive vistas. In the featured image, taken a few hours before closest approach, Saturn’s unusual northern hexagon is seen surrounding the North Pole. Saturn’s B ring is the closest visible, while the dark Cassini Division separates B from the outer A. A close inspection will find the two small moons that shepherd the F-ring,…

土星的夜面

土星的夜面

ByNASA中文

2022年11月26日 Saturn at Night NASA, JPL-Caltech, Space Science Institute, Mindaugas Macijauskas Explanation: Saturn is still bright in planet Earth’s night skies. Telescopic views of the distant gas giant and its beautiful rings often make it a star at star parties. But this stunning view of Saturn’s rings and night side just isn’t possible from telescopes closer to the Sun than the outer planet. They can only bring Saturn’s day into view. In fact, this image of Saturn’s slender sunlit crescent with night’s shadow cast across its broad and complex ring system was captured by the Cassini spacecraft. A robot spacecraft from planet Earth, Cassini called Saturn orbit home for 13 years before it was directed to dive into the atmosphere of the gas giant on…

卡西尼号的红外光土星

卡西尼号的红外光土星

ByNASA中文

2022年7月24日 Saturn in Infrared from Cassini Image Credit: NASA, JPL-Caltech, SSI; Processing: Maksim Kakitsev Explanation: Many details of Saturn appear clearly in infrared light. Bands of clouds show great structure, including long stretching storms. Also quite striking in infrared is the unusual hexagonal cloud pattern surrounding Saturn’s North Pole. Each side of the dark hexagon spans roughly the width of our Earth. The hexagon’s existence was not predicted, and its origin and likely stability remains a topic of research. Saturn’s famous rings circle the planet and cast shadows below the equator. The featured image was taken by the robotic Cassini spacecraft in 2014 in several infrared colors. In 2017 September, the Cassini mission was brought to a dramatic conclusion when the spacecraft was directed to…

土星、土卫三、行星环及暗影

土星、土卫三、行星环及暗影

ByNASA中文

2022年1月23日 Saturn, Tethys, Rings, and Shadows Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA Explanation: Seen from ice moon Tethys, rings and shadows would display fantastic views of the Saturnian system. Haven’t dropped in on Tethys lately? Then this gorgeous ringscape from the Cassini spacecraft will have to do for now. Caught in sunlight just below and left of picture center in 2005, Tethys itself is about 1,000 kilometers in diameter and orbits not quite five saturn-radii from the center of the gas giant planet. At that distance (around 300,000 kilometers) it is well outside Saturn’s main bright rings, but Tethys is still one of five major moons that find themselves within the boundaries of the faint and tenuous outer E ring. Discovered in…

土星环后方的卫星

土星环后方的卫星

ByNASA中文

2022年1月4日 Moons Beyond Rings at Saturn Image Credit: NASA, ESA, JPL, Cassini Imaging Team Explanation: What’s happened to that moon of Saturn? Nothing — Saturn’s moon Rhea is just partly hidden behind Saturn’s rings. In 2010, the robotic Cassini spacecraft then orbiting Saturn took this narrow-angle view looking across the Solar System’s most famous rings. Rings visible in the foreground include the thin F ring on the outside and the much wider A and B rings just interior to it. Although it seems to be hovering over the rings, Saturn’s moon Janus is actually far behind them. Janus is one of Saturn’s smaller moons and measures only about 180 kilometers across. Farther out from the camera is the heavily cratered Rhea, a much larger moon…

土星的夜面

土星的夜面

ByNASA中文

2021年9月11日 Saturn at Night Image Credit: NASA, JPL-Caltech, Space Science Institute, Mindaugas Macijauskas Explanation: Still bright in planet Earth’s night skies, good telescopic views of Saturn and its beautiful rings often make it a star at star parties. But this stunning view of Saturn’s rings and night side just isn’t possible from telescopes closer to the Sun than the outer planet. They can only bring Saturn’s day into view. In fact, this image of Saturn’s slender sunlit crescent with night’s shadow cast across its broad and complex ring system was captured by the Cassini spacecraft. A robot spacecraft from planet Earth, Cassini called Saturn orbit home for 13 years before it was directed to dive into the atmosphere of the gas giant on September 15,…

土星反照光里的土卫一

土星反照光里的土卫一

ByNASA中文

2021年7月30日 Mimas in Saturnlight Image Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA Explanation: Peering from the shadows, the Saturn-facing hemisphere of Mimas lies in near darkness alongside a dramatic sunlit crescent. The mosaic was captured near the Cassini spacecraft’s final close approach on January 30, 2017. Cassini’s camera was pointed in a nearly sunward direction only 45,000 kilometers from Mimas. The result is one of the highest resolution views of the icy, crater-pocked, 400 kilometer diameter moon. An enhanced version better reveals the Saturn-facing hemisphere of the synchronously rotating moon lit by sunlight reflected from Saturn itself. To see it, slide your cursor over the image (or follow this link). Other Cassini images of Mimas include the small moon’s large and ominous Herschel Crater….

透视土卫六

透视土卫六

ByNASA中文

2020年8月20日 Seeing Titan Image Credit: VIMS Team, U. Arizona, U. Nantes, ESA, NASA Explanation: Shrouded in a thick atmosphere, Saturn’s largest moon Titan really is hard to see. Small particles suspended in the upper atmosphere cause an almost impenetrable haze, strongly scattering light at visible wavelengths and hiding Titan’s surface features from prying eyes. But Titan’s surface is better imaged at infrared wavelengths where scattering is weaker and atmospheric absorption is reduced. Arrayed around this visible light image (center) of Titan are some of the clearest global infrared views of the tantalizing moon so far. In false color, the six panels present a consistent processing of 13 years of infrared image data from the Visual and Infrared Mapping Spectrometer (VIMS) on board the Cassini spacecraft….

卡西尼号太空船越过土星环面

卡西尼号太空船越过土星环面

ByNASA中文

2019 December 29 Cassini Spacecraft Crosses Saturn’s Ring Plane Image Credit: NASA, ESA, JPL, ISS, Cassini Imaging Team; Processing: Fernando Garcia Navarro Explanation: If this is Saturn, where are the rings? When Saturn’s “appendages” disappeared in 1612, Galileo did not understand why. Later that century, it became understood that Saturn’s unusual protrusions were rings and that when the Earth crosses the ring plane, the edge-on rings will appear to disappear. This is because Saturn’s rings are confined to a plane many times thinner, in proportion, than a razor blade. In modern times, the robot Cassini spacecraft orbiting Saturn frequently crossed Saturn’s ring plane during its mission to Saturn, from 2004 to 2017. A series of plane crossing images from 2005 February was dug out of…