哈勃图像: 球状星团NGC 6355

哈勃图像: 球状星团NGC 6355

2023年1月30日 Globular Star Cluster NGC 6355 from Hubble Image Credit: ESA/Hubble & NASA, E. Noyola, R. Cohen Explanation: Globular clusters once ruled the Milky Way. Back in the old days, back when our Galaxy first formed, perhaps thousands of globular clusters roamed our Galaxy. Today, there are less than 200 left. Over the eons, many globular clusters were destroyed by repeated fateful encounters with each other or the Galactic center. Surviving relics are older than any Earth fossil, older than any other structures in our Galaxy, and limit the universe itself in raw age. There are few, if any, young globular clusters left in our Milky Way Galaxy because conditions are not ripe for more to form. The featured image shows a Hubble Space Telescope…

碰撞螺旋星系Arp 274

碰撞螺旋星系Arp 274

2023年1月23日 The Colliding Spiral Galaxies of Arp 274 Image Credit: NASA, ESA, Hubble; Processing & Copyright: Mehmet Hakan Özsaraç Explanation: Two galaxies are squaring off in Virgo and here are the latest pictures. When two galaxies collide, the stars that compose them usually do not. This is because galaxies are mostly empty space and, however bright, stars only take up only a small fraction of that space. But during the collision, one galaxy can rip the other apart gravitationally, and dust and gas common to both galaxies does collide. If the two galaxies merge, black holes that likely resided in each galaxy center may eventually merge. Because the distances are so large, the whole thing takes place in slow motion — over hundreds of millions…

哈勃望远镜的蝴蝶星云

哈勃望远镜的蝴蝶星云

2022年11月21日 The Butterfly Nebula from Hubble Image Credit: NASA, ESA, Hubble; Processing: William Ostling Explanation: Stars can make beautiful patterns as they age — sometimes similar to flowers or insects. NGC 6302, the Butterfly Nebula, is a notable example. Though its gaseous wingspan covers over 3 light-years and its estimated surface temperature exceeds 200,000 degrees C, the aging central star of NGC 6302, the featured planetary nebula, has become exceptionally hot, shining brightly in visible and ultraviolet light but hidden from direct view by a dense torus of dust. This sharp close-up was recorded by the Hubble Space Telescope and is processed here to show off remarkable details of the complex planetary nebula, highlighting in particular light emitted by oxygen (shown as blue), hydrogen (green),…

棒旋星系NGC 1300

棒旋星系NGC 1300

2022年10月16日 Barred Spiral Galaxy NGC 1300 Image Credit: NASA ESA, Hubble Heritage Explanation: Across the center of this spiral galaxy is a bar. And at the center of this bar is smaller spiral. And at the center of that spiral is a supermassive black hole. This all happens in the big, beautiful, barred spiral galaxy cataloged as NGC 1300, a galaxy that lies some 70 million light-years away toward the constellation of the river Eridanus. This Hubble Space Telescope composite view of the gorgeous island universe is one of the most detailed Hubble images ever made of a complete galaxy. NGC 1300 spans over 100,000 light-years and the Hubble image reveals striking details of the galaxy’s dominant central bar and majestic spiral arms. How the…

哈勃:红外波段的马头星云

哈勃:红外波段的马头星云

2022年9月21日 The Horsehead Nebula in Infrared from Hubble Image Credit: NASA, ESA, Hubble; Processing: Alexandra Nachman Explanation: While drifting through the cosmos, a magnificent interstellar dust cloud became sculpted by stellar winds and radiation to assume a recognizable shape. Fittingly named the Horsehead Nebula, it is embedded in the vast and complex Orion Nebula (M42). A potentially rewarding but difficult object to view personally with a small telescope, the featured gorgeously detailed image was taken in infrared light by the orbiting Hubble Space Telescope. The dark molecular cloud, roughly 1,500 light years distant, is cataloged as Barnard 33 and is seen above primarily because it is backlit by the nearby massive star Sigma Orionis. The Horsehead Nebula will slowly shift its apparent shape over the…

韦伯、哈伯与昴宿的斯蒂芬五重星系

韦伯、哈伯与昴宿的斯蒂芬五重星系

2022年7月18日 Stephan’s Quintet from Webb, Hubble, and Subaru Image Credit: Webb, Hubble, Subaru; NASA, ESA, CSA, NOAJ, STScI; Processing & Copyright: Robert Gendler Explanation: OK, but why can’t you combine images from Webb and Hubble? You can, and today’s featured image shows one impressive result. Although the recently launched James Webb Space Telescope (Webb) has a larger mirror than Hubble, it specializes in infrared light and can’t see blue — only up to about orange. Conversely, the Hubble Space Telescope (Hubble) has a smaller mirror than Webb and can’t see as far into the infrared as Webb, but can image not only blue light but even ultraviolet. Therefore, Webb and Hubble data can be combined to create images across a wider variety of colors. The…

猫眼星云的中心

猫眼星云的中心

2022年7月10日 In the Center of the Cat’s Eye Nebula Credit: NASA, ESA, Hubble, HLA; Reprocessing & Copyright: Raul Villaverde Explanation: Three thousand light-years away, a dying star throws off shells of glowing gas. This image from the Hubble Space Telescope reveals the Cat’s Eye Nebula (NGC 6543), to be one of the most complex planetary nebulae known. Spanning half a light-year, the features seen in the Cat’s Eye are so complex that astronomers suspect the bright central object may actually be a binary star system. The term planetary nebula, used to describe this general class of objects, is misleading. Although these objects may appear round and planet-like in small telescopes, high resolution images with large telescopes reveal them to be stars surrounded by cocoons of…

M51:哈勃的涡状星系影像

M51:哈勃的涡状星系影像

2022年6月13日 M51: The Whirlpool Galaxy from Hubble Image Credit: NASA, ESA, Hubble, HLA; Processing & Copyright: Bernard Miller Explanation: The Whirlpool Galaxy is a classic spiral galaxy. At only 30 million light years distant and fully 60 thousand light years across, M51, also known as NGC 5194, is one of the brightest and most picturesque galaxies on the sky. The featured image is a digital combination of images taken in different colors by the Earth-orbiting Hubble Space Telescope, highlighting many sharp features. Anyone with a good pair of binoculars, however, can see this Whirlpool toward the constellation of the Hunting Dogs (Canes Venatici). M51 is a spiral galaxy of type Sc and is the dominant member of a whole group of galaxies. Astronomers speculate that…

螺旋星系NGC 1512的内环

螺旋星系NGC 1512的内环

2022年5月8日 Spiral Galaxy NGC 1512: The Inner Rings Image Credit: NASA, ESA, Hubble Space Telescope Explanation: Most galaxies don’t have any rings — why does this galaxy have two? To begin, the bright band near NGC 1512’s center is a nuclear ring, a ring that surrounds the galaxy center and glows brightly with recently formed stars. Most stars and accompanying gas and dust, however, orbit the galactic center in a ring much further out — here seen near the image edge. This ring is called, counter-intuitively, the inner ring. If you look closely, you will see this the inner ring connects ends of a diffuse central bar that runs horizontally across the galaxy. These ring structures are thought to be caused by NGC 1512’s own…

哈勃拍摄的气泡星云

哈勃拍摄的气泡星云

2022年3月23日 The Bubble Nebula from Hubble Image Credit: NASA, ESA, Hubble; Processing & Copyright: Mehmet Hakan Özsaraç Explanation: Massive stars can blow bubbles. The featured image shows perhaps the most famous of all star-bubbles, NGC 7635, also known simply as The Bubble Nebula. Although it looks delicate, the 7-light-year diameter bubble offers evidence of violent processes at work. Above and left of the Bubble’s center is a hot, O-type star, several hundred thousand times more luminous and some 45-times more massive than the Sun. A fierce stellar wind and intense radiation from that star has blasted out the structure of glowing gas against denser material in a surrounding molecular cloud. The intriguing Bubble Nebula and associated cloud complex lie a mere 7,100 light-years away toward…