土星：1993年-2022年

土星：1993年-2022年

ByNASA中文

2022年8月19日 Saturn: 1993 – 2022 Image Credit & Copyright: Tunc Tezel (TWAN) Explanation: Saturn is the most distant planet of the Solar System easily visible to the unaided eye. With this extraordinary, long-term astro-imaging project begun in 1993, you can follow the ringed gas giant for one Saturn year as it wanders once around the ecliptic plane, finishing a single orbit around the Sun by 2022. Constructed from individual images made over 29 Earth years, the split panorama is centered along the ecliptic and crossed by the plane of our Milky Way galaxy. Saturn’s position in 1993 is at the right side, upper panel in the constellation Capricornus and progresses toward the left. It returns to the spot in Capricornus at left in the lower…

满月与英仙座流星

满月与英仙座流星

ByNASA中文

2022年8月18日 Full Moon Perseids Image Credit & Copyright: Juan Carlos Casado (Starry Earth, TWAN) Explanation: The annual Perseid meteor shower was near its peak on August 13. As planet Earth crossed through streams of debris left by periodic Comet Swift-Tuttle meteors rained in northern summer night skies. But even that night’s nearly Full Moon shining near the top of this composited view couldn’t hide all of the popular shower’s meteor streaks. The image captures some of the brightest perseid meteors in many short exposures recorded over more than two hours before the dawn. It places the shower’s radiant in the heroic constellation of Perseus just behind a well-lit medieval tower in the village of Sant Llorenc de la Muga, Girona, Spain. Observed in medieval times,…

突尼斯上空的流星雨

突尼斯上空的流星雨

ByNASA中文

2022年8月16日 A Meteor Wind over Tunisia Image Credit & Copyright: Makrem Larnaout Explanation: Does the Earth ever pass through a wind of meteors? Yes, and they are frequently visible as meteor showers. Almost all meteors are sand-sized debris that escaped from a Sun-orbiting comet or asteroid, debris that continues in an elongated orbit around the Sun. Circling the same Sun, our Earth can move through an orbiting debris stream, where it can appear, over time, as a meteor wind. The meteors that light up in Earth’s atmosphere, however, are usually destroyed. Their streaks, though, can all be traced back to a single point on the sky called the radiant. The featured image composite was taken over two days in late July near the ancient Berber…

从太空看武仙T流星雨

从太空看武仙T流星雨

ByNASA中文

2022年6月4日 Tau Herculids from Space Image Credit & Copyright: Zhuoxiao Wang, Yangwang-1 Space Telescope, Origin.Space Explanation: On May 31 tens of parallel meteor streaks were recorded in this 8 degree wide field of view of planet Earth’s limb from space. The image is one of a series of 5 minute long observations by the orbiting Yangwang-1 space telescope. It was captured at 03:43 UT, near the peak of the Tau Herculid meteor shower. As predicted, the meteor shower was an active one this year, caused as Earth swept through a relatively dense stream of debris from disintegrating Comet 73P/Schwassmann-Wachmann 3, but was lacking bright meteors. Nearly all of the Tau Herculid meteors in the Yangwang-1 image are too faint to be detected by groundbased instruments….

基特峰望远镜上方的武仙T流星

基特峰望远镜上方的武仙T流星

ByNASA中文

2022年6月1日 Tau Herculids Meteors over Kitt Peak Telescopes Image Credit & Copyright: Jianwei Lyu (Steward Obs., U. Arizona) Explanation: It wasn’t the storm of the century — but it was a night to remember. Last night was the peak of the Tau Herculids meteor shower, a usually modest dribble of occasional meteors originating from the disintegrating Comet 73P/Schwassmann-Wachmann 3. This year, calculations showed that the Earth might be passing through a particularly dense stream of comet debris — at best creating a storm of bright meteors streaking out from the constellation of Hercules. What actually happened fell short of a meteor storm, but could be called a decent meteor shower. Featured here is a composite image taken at Kitt Peak National Observatory in Arizona, USA…

湖面上空的天琴流星

湖面上空的天琴流星

ByNASA中文

2022年4月28日 Lyrid of the Lake Image Credit & Copyright: Jeff Dai (TWAN) Explanation: In the early hours of April 24 this bright Lyrid meteor flashed along the central Milky Way. For a moment, it cast a bright reflection across Lake Nian, Yunnan province, China. The annual Lyrid meteor shower, one of the oldest known, is active in late April, as our fair planet plows through dust left along the orbit of long-period comet Thatcher. The trail of the bright fireball points back toward the shower’s radiant in the constellation Lyra high in the northern springtime sky and off the top of the frame. Just rising in that starry sky, light from a third quarter moon also cast a glow on the peaceful waters of the…

北半球的四分仪座流星雨

北半球的四分仪座流星雨

ByNASA中文

2022年1月8日 Quadrantids of the North Image Credit & Copyright: Cheng Luo Explanation: Named for a forgotten constellation, the Quadrantid Meteor Shower puts on an annual show for planet Earth’s northern hemisphere skygazers. The shower’s radiant on the sky lies within the old, astronomically obsolete constellation Quadrans Muralis. That location is not far from the Big Dipper, at the boundaries of the modern constellations Bootes and Draco. In fact north star Polaris is just below center in this frame and the Big Dipper asterism (known to some as the Plough) is above it, with the meteor shower radiant to the right. Pointing back toward the radiant, Quadrantid meteors streak through the night in the panoramic skyscape, a composite of images taken in the hours around the…

北半球的双子流星

北半球的双子流星

ByNASA中文

2021年12月17日 Geminid of the North Image Credit & Copyright: Alvin Wu Explanation: An arid expanse of the Tengger Desert in north-central China, planet Earth fills the foreground of this starry scene. A widefield panoramic view, it was recorded shortly after moonset in the local predawn hours of December 14. Pictured in the still dark sky, stars of the northern winter hexagon surround a luminous Milky Way. Seen near the peak of the annual meteor shower, the startling flash of a bright Geminid fireball meteor was also captured on that night. Above the western horizon and just below bright star Capella, its dagger-like trail points back to the meteor shower’s radiant in Gemini. Of course, the constellation Gemini is easy to spot. Its twin bright stars,…

南半球的双子座流星雨

南半球的双子座流星雨

ByNASA中文

2021年12月16日 Geminids of the South Image Credit & Copyright: Fefo Bouvier Explanation: Fireflies flash along a moonlit countryside in this scene taken on the night of December 13/14 from southern Uruguay, planet Earth. On that night meteors fell in the partly cloudy skies above during the annual Geminid meteor shower. Frames recorded over a period of 1.5 hours are aligned in the composite image made with the camera facing south. That direction was opposite the shower’s radiant toward the north and so the Geminid meteor streaks appear to converge at an antiradiant below the southern horizon. The shower’s apparent radiant (and antiradiant) is just due to perspective though. As Earth sweeps through the dust trail of mysterious asteroid 3200 Phaethon, the dust grains that create…

双子座流星雨：NASA将直播12月天空的年度亮点

双子座流星雨：NASA将直播12月天空的年度亮点

ByNASA中文

每年十二月，我们都有机会看到我们最喜欢的流星雨之一——双子座流星雨。此次流星雨将持续到17日，并将在13日晚至14日上午达到高峰，这是观看流星雨的最佳时间。 所有的流星似乎都来自天空中的同一个地方，称为辐射点。双子座流星雨似乎从双子座中的一个点辐射出来，因此得名“双子座流星雨”。该图显示了NASA火球网络在2020年12月观测到的388颗时速为35公里/秒的流星的辐射。所有的辐射点都在双子座，这意味着它们属于双子座流星雨。 影像来源：美国宇航局 双子座是由一个被称为3200法厄同的天体的碎片造成的，它的起源是一些争论的话题。一些天文学家认为它是一颗已灭绝的彗星，根据观测结果表明，有少量物质离开法厄同的表面。另一些人则认为它一定是小行星，因为它的轨道和它与主带小行星帕拉斯相似。 无论法厄同的性质如何，观察结果显示，双子座流星雨的密度比其他流星雨的密度要大，使得它们在燃烧之前能到达地球表面29英里的高空。其他流星雨，如英仙座流星雨，则在更高处开始燃烧。 双子座在世界上大部分地方都能看到。然而，最好的观测地点是在北半球。当你进入南半球并向南极移动时，双子座流星雨的高度——天空中出现双子座流星雨的地方——会越来越低。因此，这些地方的观测者看到的双子座流星比北部的观测者要少。 在天气方面，月亮的相位是决定流星雨在任何一年中是否会有好的流星雨的主要因素。这是因为月光“洗掉”了较暗的流星，导致天空观测者看到的明亮流星较少。今年，在双子座的顶峰时，月亮将有近80%的满月，这对我们备受推崇的流星雨来说并不理想。尽管如此，无论你在哪里，明亮的月亮预计将在凌晨2点左右落下，留下几个小时的时间观察流星雨直到黎明。 位于阿拉巴马州亨茨维尔马歇尔航天飞行中心的NASA流星体环境办公室负责人比尔·库克说:“双子座流星雨中充满了绿色的火球，是我在寒冷的12月夜晚唯一能看到的流星雨。” NASA将通过位于阿拉巴马州亨茨维尔的马歇尔太空飞行中心的流星雨摄像机，从12月13日至14日在美国东部时间晚上8点开始，在NASA流星观察Facebook页面上直播流星雨的高峰（如果我们的天气合作！）。 每天早上，全天空火球网络录制的流星视频也可用于识别这些视频中的双子座——只需查找标有“GEM”的事件即可。 在下面了解有关双子座流星雨的更多信息： 为什么他们被称为双子座？ 所有与流星雨相关的流星都有相似的轨道，它们似乎都来自天空中的同一个地方，称为辐射点。双子座流星雨似乎从双子座中的一个点辐射出来，因此得名“双子座流星雨”。 双子座流星雨的速度有多快？ 双子座流星雨的速度为78,000英里/小时（35公里/秒）。这比猎豹快1000多倍，比世界上最快的汽车快约250倍，比高速行驶的子弹快40多倍！ 如何观测双子座流星雨？ 如果不是阴天，请远离强光，仰卧并抬头。记住让你的眼睛适应黑暗——这样你会看到更多的流星。请记住，此调整可能需要大约30分钟。不要看手机屏幕，它会毁了你的夜视能力！ 流星一般在天空中随处可见。避免观看辐射点，因为靠近它的流星的轨迹很短，很容易错过。当你看到流星时，试着向后追踪它。如果你在双子座结束，很有可能你已经看到了双子座。 在光污染严重的城市中观察会很难看到双子座流星雨。在这种情况下，您可能在夜间只能看到少数几个流星。 观测双子座流星雨的最佳时间是什么时候？ 观测双子座流星雨的最佳夜晚是12月13日/14日。北半球的天空观测者可以在12月13日深夜外出观看一些双子座流星雨，但在月光和低空辐射的情况下，您可能看不到很多流星。 最佳观测时间将在当地时间12月14日凌晨2点（包括南半球），此时辐射点位在天空中的最高点。月亮将在同一时间落下。因此，从月落到12月14日黎明的观测应该会看到最多的流星。 12月13/14日有多少颗双子座流星？ 实际上，北半球观测者预测的流星雨速率接近每小时30-40颗。南半球的观测者将比北半球的观测者看到更少的双子座流星——可能是北半球的25%。、 虽然今年的天气条件不是观看双子座流星雨的最佳时机，但它仍将是我们在夜空中观看的一个很好的表演。 如果你想知道12月的天空中还会发射什么，看看喷气推进实验室每月推出的“观星指南”系列视频： 观星愉快！