飞越金星

飞越金星

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2021年02月25日 A Venus Flyby Image Credit: NASA, JHUAPL, Naval Research Lab, Guillermo Stenborg and Brendan Gallagher Explanation: On a mission to explore the inner heliosphere and solar corona, on July 11, 2020 the Wide-field Imager on board NASA’s Parker Solar Probe captured this stunning view of the nightside of Venus at distance of about 12,400 kilometers (7,693 miles). The spacecraft was making the third of seven gravity-assist flybys of the inner planet. The gravity-asssist flybys are designed to use the approach to Venus to help the probe alter its orbit to ultimately come within 6 million kilometers (4 million miles) of the solar surface in late 2025. A surprising image, the side-looking camera seems to peer through the clouds to show a dark feature near…

螺旋星系M66的哈勃影像

螺旋星系M66的哈勃影像

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2021年02月24日 Spiral Galaxy M66 from Hubble Image Credit: NASA, ESA, Hubble, Janice Lee; Processing & Copyright: Leo Shatz; Text: Karen Masters Explanation: It’s always nice to get a new view of an old friend. This stunning Hubble Space Telescope image of nearby spiral galaxy M66 is just that. A spiral galaxy with a small central bar, M66 is a member of the Leo Galaxy Triplet, a group of three galaxies about 30 million light years from us. The Leo Triplet is a popular target for relatively small telescopes, in part because M66 and its galactic companions M65 and NGC 3628 all appear separated by about the angular width of a full moon. The featured image of M66 was taken by Hubble to help investigate the…

影片：毅力号着陆火星

影片：毅力号着陆火星

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2021年02月23日 Video: Perseverance Landing on Mars Video Credit: NASA/JPL-Caltech, Mars 2020 Mission Team Explanation: What would it look like to land on Mars? To better monitor the instruments involved in the Entry, Decent, and Landing of the Perseverance Rover on Mars last week, cameras with video capability were included that have now returned their images. The featured 3.5-minute composite video begins with the opening of a huge parachute that dramatically slows the speeding spacecraft as it enters the Martian atmosphere. Next the heat shield is seen separating and falls ahead. As Perseverance descends, Mars looms large and its surface becomes increasingly detailed. At just past 2-minutes into the video, the parachute is released and Perseverance begins to land with dust-scattering rockets. Soon the Sky Crane…

星舰之间的月出

星舰之间的月出

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2021年02月22日 Moon Rising Between Starships Image Credit & Copyright: John Kraus Explanation: What’s that on either side of the Moon? Starships. Specifically, they are launch-and-return reusable rockets being developed by SpaceX to lift cargo and eventually humans from the Earth’s surface into space. The two rockets pictured are SN9 (Serial Number 9) and SN10 which were captured near their Boca Chica, Texas launchpad last month posing below January’s full Wolf Moon. The Starships house liquid-methane engines inside rugged stainless-steel shells. SN9 was test-launched earlier this month and did well with the exception of one internal rocket that failed to relight during powered descent. SN10 continues to undergo ground tests and may be test-launched later this month. Tomorrow’s picture: space fowl 星舰之间的月出 影像提供与版权: John Kraus 说明:…

NGC 2244：蔷薇星云内的星团

NGC 2244：蔷薇星云内的星团

ByNASA中文

2021年02月21日 NGC 2244: A Star Cluster in the Rosette Nebula Image Credit & Copyright: Don Goldman Explanation: In the heart of the Rosette Nebula lies a bright open cluster of stars that lights up the nebula. The stars of NGC 2244 formed from the surrounding gas only a few million years ago. The featured image taken in January using multiple exposures and very specific colors of Sulfur (shaded red), Hydrogen (green), and Oxygen (blue), captures the central region in tremendous detail. A hot wind of particles streams away from the cluster stars and contributes to an already complex menagerie of gas and dust filaments while slowly evacuating the cluster center. The Rosette Nebula’s center measures about 50 light-years across, lies about 5,200 light-years away, and…

毅力号：如何着陆火星

毅力号：如何着陆火星

ByNASA中文

2021年02月20日 Perseverance: How to Land on Mars Image Credit: NASA, JPL, Mars 2020 Explanation: Slung beneath its rocket powered descent stage Perseverance hangs only a few meters above the martian surface, captured here moments before its February 18 touchdown on the Red Planet. The breath-taking view followed an intense seven minute trip from the top of the martian atmosphere. Part of a high resolution video, the picture was taken from the descent stage itself during the final skycrane landing maneuver. Three taut mechanical cables about 7 meters long are visible lowering Perseverance, along with an electrical umbilical connection feeding signals (like this image), to a computer on board the car-sized rover. Below Perseverance streamers of martian dust are kicked-up from the surface by the descent…

毅力号火星车的第一天

毅力号火星车的第一天

ByNASA中文

2021年02月19日 Mars Perseverance Sol 0 Image Credit: NASA, JPL, Mars 2020 Explanation: After a 203 day interplanetary voyage, and seven minutes of terror, Perseverance has landed on Mars. Confirmation of the successful landing at Jezero crater was announced from mission control at NASA’s Jet Propulsion Laboratory in Southern California at 12:55 pm PST on February 18. The car-sized Mars rover’s Front Left Hazard Avoidance Camera acquired this initial low resolution image shortly after touchdown on mission Sol 0. A protective cover is still on the camera, but the shadow of Perseverance, now the most ambitious rover sent to the Red Planet, is visible cast across the martian surface. Tomorrow’s picture: light-weekend 毅力号火星车的第一天 影像提供: NASA, JPL, Mars 2020 说明: 经过203天的行星际旅程，以及恐怖7分钟之旅后，毅力号着陆在火星上。在太平洋标准时间2月18日午后12:55，位在南加州的美国航太总署．喷射推进实验室的任务控制中心，正式确认在耶杰罗坑的著陆成功。着陆后不久，这部房车大小的火星车之左前避险相机，拍下了上面这幅初期低解析影像，标志这部火星车火星历的第一天。虽然相机仍在保护罩内，不过在影像里，仍可清楚见到这部空前的毅力号火星车，在火星表面投下的身影。 明日的图片: light-weekend

瑞士阿尔卑斯山与类火星的天空

瑞士阿尔卑斯山与类火星的天空

ByNASA中文

2021年02月18日 Swiss Alps, Martian Sky Image Credit & Copyright: Jens Bydal Explanation: Taken on February 6, this snowy mountain and skyscape was captured near Melchsee-Frutt, central Switzerland, planet Earth. The reddish daylight and blue tinted glow around the afternoon Sun are colors of the Martian sky, though. Of course both worlds have the same Sun. From Mars, the Sun looks only about half as bright and 2/3 the size compared to its appearance from Earth. Lofted from the surface of Mars, fine dust particles suspended in the thin Martian atmosphere are rich in the iron oxides that make the Red Planet red. They tend to absorb blue sunlight giving a red tinge to the Martian sky, while forward scattering still makes the light appear relatively…

日柱与上正切晕弧

日柱与上正切晕弧

ByNASA中文

2021年02月17日 Sun Pillar with Upper Tangent Arc Image Credit & Copyright: Mike Cohea Explanation: This was not a typical sun pillar. Just after sunrise two weeks ago in Providence, Rhode Island, USA, a photographer, looking out his window, was suddenly awestruck. The astonishment was caused by a sun pillar that fanned out at the top. Sun pillars, singular columns of light going up from the Sun, are themselves rare to see, and are known to be caused by sunlight reflecting from wobbling, hexagon-shaped ice-disks falling through Earth’s atmosphere. Separately, upper tangent arcs are known to be caused by sunlight refracting through falling hexagon-shaped ice-tubes. Finding a sun pillar connected to an upper tangent arc is extraordinary, and, initially, took some analysis to figure out what…

毅力号：七分钟的火星之旅

毅力号：七分钟的火星之旅

ByNASA中文

2021年02月16日 Perseverance: Seven Minutes to Mars Video Credit: NASA, JPL Explanation: How hard is it to land safely on Mars? So hard that many more attempts have failed than succeeded. The next attempt will be on Thursday. The main problem is that the Martian atmosphere is too thick to ignore — or it will melt your spacecraft. On the other hand, the atmosphere is too thin to rely on parachutes — or your spacecraft will crash land. Therefore, as outlined in the featured video, the Perseverance lander will lose much of its high speed by deploying a huge parachute, but then switch to rockets, and finally, assuming everything goes right, culminate with a hovering Sky Crane that will slowly lower the car-sized Perseverance rover to…