2020年日全食

2020年日全食

ByNASA中文

2021年01月07日 Total Solar Eclipse 2020 Image Credit & Copyright: Miloslav Druckmuller, Andreas Moller, (Brno University of Technology), Explanation: Along a narrow path crossing southern South America through Chile and Argentina, the final New Moon of 2020 moved in front of the Sun on December 14 in the year’s only total solar eclipse. Within about 2 days of perigee, the closest point in its elliptical orbit, the New Moon’s surface is faintly lit by earthshine in this dramatic composite view. The image is a processed composite of 55 calibrated exposures ranging from 1/640 to 3 seconds. Covering a large range in brightness during totality, it reveals the dim lunar surface and faint background stars, along with planet-sized prominences at the Sun’s edge, an enormous coronal mass…

火星的条纹沙丘

火星的条纹沙丘

ByNASA中文

2021年01月06日 Striped Sand Dunes on Mars Image Credit: HiRISE, MRO, LPL (U. Arizona), NASA; Processing: Włodek Głażewski; Text: Alex R. Howe (NASA/USRA, Reader’s History of SciFi Podcast) Explanation: Why are these sand dunes on Mars striped? No one is sure. The featured image shows striped dunes in Kunowsky Crater on Mars, photographed recently with the Mars Reconnaissance Orbiter’s HiRISE Camera. Many Martian dunes are known to be covered unevenly with carbon dioxide (dry ice) frost, creating patterns of light and dark areas. Carbon dioxide doesn’t melt, but sublimates, turning directly into a gas. Carbon dioxide is also a greenhouse material even as a solid, so it can trap heat under the ice and sublimate from the bottom up, causing geyser-like eruptions. During Martian spring, these…

小麦哲伦星系

小麦哲伦星系

ByNASA中文

2021年01月05日 The Small Cloud of Magellan Image Credit & Copyright: José Mtanous Explanation: What is the Small Magellanic Cloud? It has turned out to be a galaxy. People who have wondered about this little fuzzy patch in the southern sky included Portuguese navigator Ferdinand Magellan and his crew, who had plenty of time to study the unfamiliar night sky of the south during the first circumnavigation of planet Earth in the early 1500s. As a result, two celestial wonders easily visible for southern hemisphere skygazers are now known in Western culture as the Clouds of Magellan. Within the past 100 years, research has shown that these cosmic clouds are dwarf irregular galaxies, satellites of our larger spiral Milky Way Galaxy. The Small Magellanic Cloud actually…

冰岛上空的凤凰极光

冰岛上空的凤凰极光

ByNASA中文

2021年01月03日 A Phoenix Aurora over Iceland Image Credit & Copyright: Hallgrimur P. Helgason; Rollover Annotation: Judy Schmidt Explanation: All of the other aurora watchers had gone home. By 3:30 am in Iceland, on a quiet September night, much of that night’s auroras had died down. Suddenly, unexpectedly, a new burst of particles streamed down from space, lighting up the Earth’s atmosphere once again. This time, surprisingly, pareidoliacally, the night lit up with an amazing shape reminiscent of a giant phoenix. With camera equipment at the ready, two quick sky images were taken, followed immediately by a third of the land. The mountain in the background is Helgafell, while the small foreground river is called Kaldá, both located about 30 kilometers north of Iceland’s capital Reykjavík….

用21世纪棉胶湿版法拍摄的月亮

用21世纪棉胶湿版法拍摄的月亮

ByNASA中文

2021年01月02日 21st Century Wet Collodion Moon Image Credit & Copyright: Mike Smolinsky Explanation: In the mid 19th century, one of the first photographic technologies used to record the lunar surface was the wet-plate collodion process, notably employed by British astronomer Warren De la Rue. To capture an image, a thick, transparent mixture was used to coat a glass plate, sensitized with silver nitrate, exposed at the telescope, and then developed to create a negative image on the plate. To maintain photographic sensitivity, the entire process, from coating to exposure to developing, had to be completed before the plate dried, in a span of about 10 to 15 minutes. This modern version of a wet-plate collodion image celebrates lunar photography’s early days, reproducing the process using…

星系与南天极

星系与南天极

ByNASA中文

2021年01月01日 Galaxies and the South Celestial Pole Image Credit & Copyright: Petr Horalek, Josef Kujal Explanation: The South Celestial Pole is easy to spot in star trail images of the southern sky. The extension of Earth’s axis of rotation to the south, it’s at the center of all the southern star trail arcs. In this starry panorama streching about 60 degrees across deep southern skies the South Celestial Pole is somewhere near the middle though, flanked by bright galaxies and southern celestial gems. Across the top of the frame are the stars and nebulae along the plane of our own Milky Way Galaxy. Gamma Crucis, a yellowish giant star heads the Southern Cross near top center, with the dark expanse of the Coalsack nebula tucked…

返回器的迹线

返回器的迹线

ByNASA中文

2020年12月31日 Trail of the Returner Image Credit & Copyright: Zhuoxiao Wang Explanation: Familiar stars of a northern winter’s night shine in this night skyview, taken near Zhangye, Gansu, China and the border with Inner Mongolia. During the early hours of December 17 Orion is near center in the single exposure that captures a fireball streaking across the sky, almost as bright as yellowish Mars shining on the right. Splitting Gemini’s twin bright stars Castor and Pollux near the top of the frame, the fireball’s trail and timing are consistent with the second skipping atmospheric entry of the Chang’e 5 mission’s returner capsule. The returner capsule was successfully recovered after landing in Inner Mongolia, planet Earth with about 2 kilograms of lunar material on board. The…

木星与土星大近合：电影

木星与土星大近合：电影

ByNASA中文

2020年12月30日 Jupiter and Saturn Great Conjunction: The Movie Video Credit: Thanakrit Santikunaporn (National Astronomical Research Institute of Thailand); Text: Matipon Tangmatitham Explanation: Yes, but have you seen a movie of Jupiter and Saturn’s Great Conjunction? The featured time-lapse video was composed from a series of images taken from Thailand and shows the two giant planets as they angularly passed about a tenth of a degree from each other. The first Great Conjunction sequence shows a relative close up over five days with moons and cloud bands easily visible, followed by a second video sequence, zoomed out, over 9 days. Even though Jupiter and Saturn appeared to pass unusually close together on the sky on December 21, 2020, in actuality they were still nearly a billion…

日全食期间的地球

日全食期间的地球

ByNASA中文

2020年12月29日 Earth During a Total Solar Eclipse Video Credit: GOES-16, ABI, NOAA, NASA Explanation: What does the Earth look like during a total solar eclipse? It appears dark in the region where people see the eclipse, because that’s where the shadow of the Moon falls. The shadow spot rapidly shoots across the Earth at nearly 2,000 kilometers per hour, darkening locations in its path — typically for only a few minutes — before moving on. The featured video shows the Earth during the total solar eclipse earlier this month. The time-lapse sequence, taken from a geostationary satellite, starts with the Earth below showing night but the sun soon rises at the lower right. Clouds shift as day breaks over the blue planet. Suddenly the circular…

M16：老鹰星云的内部

M16：老鹰星云的内部

ByNASA中文

2020年12月28日 M16: Inside the Eagle Nebula Image Credit & Copyright: Nicolas Paladini Explanation: From afar, the whole thing looks like an Eagle. A closer look at the Eagle Nebula, however, shows the bright region is actually a window into the center of a larger dark shell of dust. Through this window, a brightly-lit workshop appears where a whole open cluster of stars is being formed. In this cavity tall pillars and round globules of dark dust and cold molecular gas remain where stars are still forming. Already visible are several young bright blue stars whose light and winds are burning away and pushing back the remaining filaments and walls of gas and dust. The Eagle emission nebula, tagged M16, lies about 6500 light years away,…