十二月的仲夏夜

十二月的仲夏夜

ByNASA中文

2023年12月23日 A December Summer Night Image Credit & Copyright: Ian Griffin (Otago Museum) Explanation: Colours of a serene evening sky are captured in this 8 minute exposure, made near this December’s solstice from New Zealand, southern hemisphere, planet Earth. Looking south, star trails form the short concentric arcs around the rotating planet’s south celestial pole positioned just off the top of the frame. At top and left of center are trails of the Southern Cross stars and a dark smudge from the Milky Way’s Coalsack Nebula. Alpha and Beta Centauri make the brighter yellow and blue tinted trails, reflected below in the waters of Hoopers Inlet in the Pacific coast of the South Island’s Otago Peninsula. On that short December summer night, aurora australis also…

阳光下的183天

阳光下的183天

ByNASA中文

2023年12月22日 183 Days in the Sun Image Credit & Copyright: José Zarcos Palma Explanation: A single 183 day exposure with a pinhole camera and photographic paper resulted in this long-duration solargraph. Recorded from solstice to solstice, June 21 to December 21, in 2022, it follows the Sun’s daily arcing path through planet Earth’s skies from Mertola, Portugal. On June 21, the Sun’s highest point and longest arc represents the longest day and the astronomical beginning of summer in the northern hemisphere. The solstice date with the fewest hours of daylight is at the beginning of winter in the north, corresponding to the Sun’s shortest and lowest arc in the 2022 solargraph. For 2023, the northern winter solstice was on December 22 at 3:27 UTC. That’s…

三个星系与一颗彗星

三个星系与一颗彗星

ByNASA中文

2023年12月21日 Three Galaxies and a Comet Image Credit & Copyright: Dan Bartlett Explanation: Distant galaxies abound in this one degree wide field of view toward the southern constellation Grus (The Crane). But the three spiral galaxies at the lower right are quite striking. In fact, all three galaxies are grouped about 70 million light years away and sometimes known as the Grus Triplet. They share the pretty telescopic frame, recorded on December 13, with the comet designated C/2020 V2 ZTF. Now outbound from the inner Solar System and swinging below the ecliptic plane in a hyperbolic orbit, the comet was about 29 light-minutes from our fair planet in this image. And though comet ZTF was brighter when it was closest to the Sun last May…

研究一场有计划的火灾

研究一场有计划的火灾

ByNASA中文

Flames burn orange through green conifers and golden aspen on the slopes of Monroe Mountain in Utah’s Fishlake National Forest, sending gray and brown smoke billowing into the sky in this image from Oct. 9, 2023. This fire was intentionally set with a fire-dripping device suspended from a helicopter. The burn aimed to reintroduce fire to the Monroe Mountain region. Fire promotes aspen regeneration and reduces accumulated brush and dead vegetation that could fuel a larger uncontrolled fire. Scientists from NASA’s FireSense project, along with dozens of others from the Forest Service and other organizations and universities, collected data from the ground and from the sky as part of the Forest Service’s Fire and Smoke Model Evaluation Experiment. Observing a prescribed high-intensity fire gave NASA…

明亮的星星照亮了“圣诞树星团”

明亮的星星照亮了“圣诞树星团”

ByNASA中文

影像来源：X射线：NASA/CXC/SAO; 可见光：T.A. Rector (NRAO/AUI/NSF and NOIRLab/NSF/AURA) and B.A. Wolpa (NOIRLab/NSF/AURA); 红外线：NASA/NSF/IPAC/CalTech/Univ. of Massachusetts; 影像处理：NASA/CXC/SAO/L. Frattare & J.Major 这张NGC 2264的新图像，也被称为“圣诞树星团”，显示了一棵带有恒星光芒的宇宙树的形状。事实上，NGC 2264是我们银河系中的一个年轻恒星群，年龄在100万到500万年之间，距离地球约2,500光年。NGC 2264中的恒星有比太阳小的，也有比太阳大的，有的质量不到太阳的十分之一，有的质量约为太阳的七倍。 这张新的合成图像通过颜色和旋转的选择增强了与圣诞树的相似性。蓝色和白色的光（在这张图片的动画版本中闪烁）是NASA的钱德拉X射线天文台探测到的发出X射线的年轻恒星。来自美国国家科学基金会位于基特峰的WIYN 0.9米望远镜的光学数据显示，星云中的气体为绿色，与圣诞树的“松针”相对应，来自两微米全天巡天的红外数据显示白色的前景和背景恒星。这张图片已经从天文学家的标准北向上顺时针旋转了大约160度，所以看起来树的顶端朝向图片的顶部。 这张合成图像显示了圣诞树星团。蓝色和白色的光（在这张图片的动画版本中闪烁）是NASA的钱德拉X射线天文台探测到的发出X射线的年轻恒星。来自美国国家科学基金会位于基特峰的WIYN 0.9米望远镜的光学数据显示，星云中的气体为绿色，与圣诞树的“松针”相对应，来自两微米全天巡天的红外数据显示白色的前景和背景恒星。这张图片已经从天文学家的标准北向上顺时针旋转了大约160度，所以看起来树的顶端朝向图片的顶部。 年轻的恒星，如NGC 2264中的那些，是不稳定的，在X射线和其他不同类型的光中可以看到强烈的耀斑。然而，该动画中显示的协调、闪烁的变化是人为的，以强调X射线中看到的恒星的位置，并突出显示该天体与圣诞树的相似性。实际上，恒星的变化并不同步。 钱德拉和其他望远镜观察到的变化是由几种不同的过程引起的。其中一些与涉及磁场的活动有关，包括像太阳那样所经历的耀斑——但比太阳强得多——以及随着恒星旋转而进出视野的恒星表面的热点和黑暗区域。遮蔽恒星的气体的厚度也会发生变化，从周围气体盘上落在恒星上的物质的数量也会发生变化。 NASA马歇尔太空飞行中心负责管理钱德拉计划。史密森天体物理天文台的钱德拉X射线中心控制着马萨诸塞州剑桥市的科学操作和马萨诸塞年伯灵顿市的飞行操作。 阅读更多来自NASA钱德拉X射线天文台的信息。 如欲了解更多钱德拉影像、多媒体及相关资料，请访问: https://www.nasa.gov/mission/chandra-x-ray-observatory/ 视频文稿 这份新闻稿展示了一个年轻恒星群的合成图像，看起来就像一棵宇宙圣诞树！这个被称为NGC 2264的星团位于我们的银河系，距离地球大约2,500光年。星团中的一些恒星相对较小，一些相对较大，质量从我们太阳的十分之一到七倍不等。 在这张合成图像中，星团与圣诞树的相似性通过图像旋转和颜色选择得到了增强。光学数据由纤细的绿色线条和形状表示，这形成了树形的树枝和针叶。钱德拉探测到的X射线呈现为蓝色和白色的光，类似于树上的发光点。红外数据显示前景和背景恒星是黑暗太空中闪烁的白色斑点。这幅图像已经从天文学家的标准北向上旋转了大约150度。这使得这个大致呈圆锥形的树的顶点靠近图像的顶部，尽管它没有处理在我们右下角的树枝上轻微的裸露部分，它可能应该转向角落。 在这个版本中，节日星团以静态图像和简短动画的形式呈现。在动画中，钱德拉的蓝色和白色X射线点在树上闪烁，就像圣诞树上的灯一样。 参考来源： https://www.nasa.gov/image-article/telescopes-illuminate-christmas-tree-cluster/

巴伐利亚上空的冰晕

巴伐利亚上空的冰晕

ByNASA中文

2023年12月20日 Ice Halos over Bavaria Image Credit & Copyright: Bastian Werner Explanation: What’s causing those unusual sky arcs? Ice crystals. While crossing a field of fresh snow near Füssen, Bavaria, Germany, earlier this month, the photographer noticed that he had entered an ice fog. For suspended water to freeze into an ice fog requires quite cold temperatures, and indeed the air temperature on this day was measured at well below zero. The ice fog reflected light from the Sun setting behind St. Coleman Church. The result was one of the greatest spectacles the photographer has ever seen. First, the spots in the featured picture are not background stars but suspended ice and snow. Next, two prominent ice halos are visible: the 22-degree halo and the…

NGC 1499: 加州星云

NGC 1499: 加州星云

ByNASA中文

2023年12月19日 NGC 1499: The California Nebula Image Credit & Copyright: Steven Powell Explanation: Could Queen Calafia‘s mythical island exist in space? Perhaps not, but by chance the outline of this molecular space cloud echoes the outline of the state of California, USA. Our Sun has its home within the Milky Way’s Orion Arm, only about 1,000 light-years from the California Nebula. Also known as NGC 1499, the classic emission nebula is around 100 light-years long. On the featured image, the most prominent glow of the California Nebula is the red light characteristic of hydrogen atoms recombining with long lost electrons, stripped away (ionized) by energetic starlight. The star most likely providing the energetic starlight that ionizes much of the nebular gas is the bright, hot,…

火星上的冰流

火星上的冰流

ByNASA中文

On Aug. 18, 2023, the Mars Reconnaissance Orbiter (MRO) captured ridged lines carved onto Mars’ landscape by the gradual movement of ice. While surface ice deposits are mostly limited to Mars’ polar caps, these patterns appear in many non-polar Martian regions. As ice flows downhill, rock and soil are plucked from the surrounding landscape and ferried along the flowing ice surface and within the icy subsurface. While this process takes perhaps thousands of years or longer, it creates a network of linear patterns that reveal the history of ice flow. The MRO has been studying Mars since 2006. Its instruments zoom in for extreme close-up photography of the Martian surface, analyze minerals, look for subsurface water, trace how much dust and water are distributed in…

同色错觉

同色错觉

ByNASA中文

2023年12月18日 The Same Color Illusion Image Credit: Edward H. Adelson, Wikipedia Explanation: Are squares A and B the same color? They are! To verify this, either run your cursor over the image or click here to see them connected. The featured illusion, an example of the same color illusion, illustrates that purely human perceptions in science may be ambiguous or inaccurate, even such a seemingly direct perception as relative color. Similar illusions exist on the sky, such as the size of the Moon near the horizon, or the apparent shapes of astronomical objects. The advent of automated, reproducible measuring devices such as CCDs have made science in general and astronomy in particular less prone to, but not free of, human-biased illusions. APOD Year in Review…

首次动力控制飞行120周年纪念

首次动力控制飞行120周年纪念

ByNASA中文

In this image from Dec. 17, 1903, Orville Wright makes the first powered, controlled flight on Earth as his brother Wilbur looks on. Orville Wright covered 120 feet in 12 seconds during the first flight of the day. The Wright brothers made four flights that day, each longer than the last. The aircraft, Flyer 1, was wrecked beyond repair after the fourth flight, but Orville took the wreckage home to Ohio and restored it. It went on display at the London Science Museum until 1948 when the Smithsonian Institution took ownership. The Wrights’ legacy has traveled beyond Earth; engineers attached a postage-stamp-sized piece of Flyer 1’s wing material to a cable underneath NASA’s Ingenuity Mars Helicopter. As of Dec. 2, 2023, Ingenuity has traveled a…