M20与M21

M20与M21

2019 December 30 Messier 20 and 21 Image Credit & Copyright: Stanislav Volskiy, Chilescope Team Explanation: The beautiful Trifid Nebula, also known as Messier 20, is easy to find with a small telescope in the nebula rich constellation Sagittarius. About 5,000 light-years away, the colorful study in cosmic contrasts shares this well-composed, nearly 1 degree wide field with open star cluster Messier 21 (top left). Trisected by dust lanes the Trifid itself is about 40 light-years across and a mere 300,000 years old. That makes it one of the youngest star forming regions in our sky, with newborn and embryonic stars embedded in its natal dust and gas clouds. Estimates of the distance to open star cluster M21 are similar to M20’s, but though they…

雪花星团

雪花星团

Newborn stars, hidden behind thick dust, are revealed in this image of a section of the so-called Christmas Tree Cluster from NASA’s Spitzer Space Telescope. The newly revealed infant stars appear as pink and red specks toward the center and appear to have formed in regularly spaced intervals along linear structures in a configuration that resembles the spokes of a wheel or the pattern of a snowflake. Hence, astronomers have nicknamed this the “Snowflake Cluster.” Star-forming clouds like this one are dynamic and evolving structures. Since the stars trace the straight line pattern of spokes of a wheel, scientists believe that these are newborn stars, or “protostars.” At a mere 100,000 years old, these infant structures have yet to “crawl” away from their location of…

船底座星云的“神秘山”

船底座星云的“神秘山”

Within the tempestuous Carina Nebula lies “Mystic Mountain.” This three-light-year-tall cosmic pinnacle, imaged by the Hubble Space Telescope’s Wide Field Camera 3 in 2010, is made up primarily of dust and gas, and exhibits signs of intense star-forming activity. The colors in this composite image correspond to the glow of oxygen (blue), hydrogen and nitrogen (green) and sulfur (red). Image Credit: NASA, ESA, M. Livio and the Hubble 20th Anniversary Team (STScI) 在汹涌的船底座星云中坐落着一座“神秘山”。2010年,哈勃太空望远镜的广角相机3号拍摄到了这个三光年高的宇宙尖塔,它主要由尘埃和气体组成,并显示出强烈的恒星形成活动的迹象。这张合成图中的颜色分别代表了氧(蓝色)、氢和氮(绿色)和硫(红色)的辉光。 图片来源:NASA, ESA, M. Livio and the Hubble 20th Anniversary Team (STScI)

M42:猎户座星云内部

M42:猎户座星云内部

2019 October 30 M42: Inside the Orion Nebula Image Credit & Copyright: Josep M. Drudis & Don Goldman Explanation: The Great Nebula in Orion, an immense, nearby starbirth region, is probably the most famous of all astronomical nebulas. Here, glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1500 light-years away. In the featured deep image in assigned colors highlighted by emission in oxygen and hydrogen, wisps and sheets of dust and gas are particularly evident. The Great Nebula in Orion can be found with the unaided eye near the easily identifiable belt of three stars in the popular constellation Orion. In addition to housing a bright open cluster of stars known as the Trapezium, the Orion Nebula…

头顶的星系

头顶的星系

2019 October 15 The Galaxy Above Image Credit & Copyright: Rodrigo Guerra Explanation: Have you contemplated your home galaxy lately? If your sky looked like this, perhaps you’d contemplate it more often! The featured picture is actually a composite of two images taken last month from the same location in south Brazil and with the same camera — but a few hours apart. The person in the image — also the astrophotographer — has much to see in the Milky Way Galaxy above. The central band of our home Galaxy stretches diagonally up from the lower left. This band is dotted with spectacular sights including dark nebular filaments, bright blue stars, and red nebulas. Millions of fainter and redder stars fill in the deep Galactic…

带注解的银心影像

带注解的银心影像

2019 September 27 The Annotated Galactic Center Image Credit & Copyright: Miguel Claro (TWAN, Dark Sky Alqueva) Explanation: The center of our Milky Way galaxy can be found some 26,000 light-years away toward the constellation Sagittarius. Even on a dark night, you can’t really see it though. Gaze in that direction, and your sight-line is quickly obscured by intervening interstellar dust. In fact, dark dust clouds, glowing nebulae, and crowded starfieds are packed along the fertile galactic plane and central regions of our galaxy. This annotated view, a mosaic of dark sky images, highlights some favorites, particularly for small telescope or binocular equipped skygazers. The cropped version puts the direction to the galactic center on the far right. It identifies well-known Messier objects like the…

哈勃望远镜拍摄到恒星生命的最后阶段

哈勃望远镜拍摄到恒星生命的最后阶段

This image from the NASA/ESA Hubble Space Telescope shows NGC 5307, a planetary nebula that lies about 10,000 light-years from Earth. It can be seen in the constellation Centaurus (the Centaur), which can be seen primarily in the southern hemisphere. A planetary nebula is the final stage of a Sun-like star. As such, planetary nebulas allow us a glimpse into the future of our own solar system. A star like our Sun will, at the end of its life, transform into a red giant. Stars are sustained by the nuclear fusion that occurs in their core, which creates energy. The nuclear fusion processes constantly try to rip the star apart. Only the gravity of the star prevents this from happening. At the end of the…

哈勃太空望远镜拍摄到了动态垂死的恒星

哈勃太空望远镜拍摄到了动态垂死的恒星

This atmospheric image taken with the NASA/ESA Hubble Space Telescope shows a dark, gloomy scene in the constellation of Gemini (the Twins). The subject of this image confused astronomers when it was first studied — rather than being classified as a single object, it was instead recorded as two objects, owing to its symmetrical lobed structure (known as NGC 2371 and NGC 2372, though sometimes referred to together as NGC 2371/2). These two lobes are visible to the lower left and upper right of the frame, and together form something known as a planetary nebula. Despite the name, such nebulas have nothing to do with planets; NGC 2371/2 formed when a Sun-like star reached the end of its life and blasted off its outer layers,…

哈勃太空望远镜拍摄的恒星气体发光的照片

哈勃太空望远镜拍摄的恒星气体发光的照片

Although it looks more like an entity seen through a microscope than a telescope, this rounded object, named NGC 2022, is certainly not algae or tiny, blobby jellyfish. Instead, it is a vast orb of gas in space, cast off by an aging star. The star is visible in the orb’s center, shining through the gases it formerly held onto for most of its stellar life. When stars like the Sun grow advanced in age, they expand and glow red. These so-called red giants then begin to lose their outer layers of material into space. More than half of such a star’s mass can be shed in this manner, forming a shell of surrounding gas. At the same time, the star’s core shrinks and grows…