玫瑰不必是红色的

玫瑰不必是红色的

BySamuel Chan

2024年2月9日 When Roses Aren’t Red Image Credit & Copyright: Tommy Lease (Denver Astronomical Society) Explanation: Not all roses are red of course, but they can still be very pretty. Likewise, the beautiful Rosette Nebula and other star forming regions are often shown in astronomical images with a predominately red hue, in part because the dominant emission in the nebula is from hydrogen atoms. Hydrogen’s strongest optical emission line, known as H-alpha, is in the red region of the spectrum. But the beauty of an emission nebula need not be appreciated in red light alone. Other atoms in the nebula are also excited by energetic starlight and produce narrow emission lines as well. In this close-up view of the Rosette Nebula, narrowband images are mapped into…

球状星团杜鹃47

球状星团杜鹃47

BySamuel Chan

2024年2月8日 Globular Star Cluster 47 Tuc Image Credit & Copyright: Marco Lorenzi, Angus Lau, Tommy Tse Explanation: Globular star cluster 47 Tucanae is a jewel of the southern sky. Also known as NGC 104, it roams the halo of our Milky Way Galaxy along with some 200 other globular star clusters. The second brightest globular cluster (after Omega Centauri) as seen from planet Earth, 47 Tuc lies about 13,000 light-years away. It can be spotted with the naked-eye close on the sky to the Small Magellanic Cloud in the constellation of the Toucan. The dense cluster is made up of hundreds of thousands of stars in a volume only about 120 light-years across. Red giant stars on the outskirts of the cluster are easy to…

心形的触须星系

心形的触须星系

BySamuel Chan

2024年2月7日 The Heart Shaped Antennae Galaxies Image Credit & Copyright: Kent E. Biggs Explanation: Are these two galaxies really attracted to each other? Yes, gravitationally, and the result appears as an enormous iconic heart — at least for now. Pictured is the pair of galaxies cataloged as NGC 4038 and NGC 4039,known as the Antennae Galaxies. Because they are only 60 million light years away, close by intergalactic standards, the pair is one of the best studied interacting galaxies on the night sky. Their strong attraction began about a billion years ago when they passed unusually close to each other. As the two galaxies interact, their stars rarely collide, but new stars are formed when their interstellar gases crash together. Some new stars have already…

NGC 1566: 韦伯与哈勃的螺旋星系影像

NGC 1566: 韦伯与哈勃的螺旋星系影像

BySamuel Chan

2024年2月6日 NGC 1566: A Spiral Galaxy from Webb and Hubble Image Credit & Copyright: NASA, ESA, CSA, STScI, J. Lee (STScI), T. Williams (Oxford), R. Chandar (UToledo), D. Calzetti (UMass), PHANGS Team Explanation: What’s different about this galaxy? Very little, which makes the Spanish Dancer galaxy, NGC 1566, one of the most typical and photogenic spirals on the sky. There is something different about this galaxy image, though, because it is a diagonal combination of two images: one by the Hubble Space Telescope on the upper left, and the other by the James Webb Space Telescope on the lower right. The Hubble image was taken in ultraviolet light and highlights the locations of bright blue stars and dark dust along the galaxy’s impressive spiral arms….

船底座星云的核心

船底座星云的核心

BySamuel Chan

2024年2月5日 In the Core of the Carina Nebula Image Credit & Copyright: Carlos Taylor Explanation: What’s happening in the core of the Carina Nebula? Stars are forming, dying, and leaving an impressive tapestry of dark dusty filaments. The entire Carina Nebula, cataloged as NGC 3372, spans over 300 light years and lies about 8,500 light-years away in the constellation of Carina. The nebula is composed predominantly of hydrogen gas, which emits the pervasive red and orange glows seen mostly in the center of this highly detailed featured image. The blue glow around the edges is created primarily by a trace amount of glowing oxygen. Young and massive stars located in the nebula’s center expel dust when they explode in supernovas. Eta Carinae, the most energetic…

哈勃影像: 锥状星云

哈勃影像: 锥状星云

BySamuel Chan

2024年2月4日 The Cone Nebula from Hubble Image Credit: Hubble Legacy Archive, NASA, ESA – Processing & Licence: Judy Schmidt Explanation: Stars are forming in the gigantic dust pillar called the Cone Nebula. Cones, pillars, and majestic flowing shapes abound in stellar nurseries where natal clouds of gas and dust are buffeted by energetic winds from newborn stars. The Cone Nebula, a well-known example, lies within the bright galactic star-forming region NGC 2264. The Cone was captured in unprecedented detail in this close-up composite of several observations from the Earth-orbiting Hubble Space Telescope. While the Cone Nebula, about 2,500 light-years away in Monoceros, is around 7 light-years long, the region pictured here surrounding the cone’s blunted head is a mere 2.5 light-years across. In our neck…

阿波罗14号: 蝎心号登月舱的景观

阿波罗14号: 蝎心号登月舱的景观

BySamuel Chan

2024年2月3日 Apollo 14: A View from Antares Image Credit: Edgar Mitchell, Apollo 14, NASA; Mosaic – Eric M. Jones Explanation: Apollo 14’s Lunar Module Antares landed on the Moon on February 5, 1971. Toward the end of the stay astronaut Ed Mitchell snapped a series of photos of the lunar surface while looking out a window, assembled into this detailed mosaic by Apollo Lunar Surface Journal editor Eric Jones. The view looks across the Fra Mauro highlands to the northwest of the landing site after the Apollo 14 astronauts had completed their second and final walk on the Moon. Prominent in the foreground is their Modular Equipment Transporter, a two-wheeled, rickshaw-like device used to carry tools and samples. Near the horizon at top center is…

NGC 1893与IC 410的蝌蚪

NGC 1893与IC 410的蝌蚪

BySamuel Chan

2024年2月2日 NGC 1893 and the Tadpoles of IC 410 Image Credit & Copyright: Sander de Jong Explanation: This cosmic view shows off an otherwise faint emission nebula IC 410, captured under clear Netherlands skies with telescope and narrowband filters. Above and right of center you can spot two remarkable inhabitants of the interstellar pond of gas and dust, known as the tadpoles of IC 410. Partly obscured by foreground dust, the nebula itself surrounds NGC 1893, a young galactic cluster of stars. Formed in the interstellar cloud a mere 4 million years ago, the intensely hot, bright cluster stars energize the glowing gas. Globules composed of denser cooler gas and dust, the tadpoles are around 10 light-years long and are likely sites of ongoing star…

NGC 1365: 壮丽的宇宙岛

NGC 1365: 壮丽的宇宙岛

BySamuel Chan

2024年2月1日 NGC 1365: Majestic Island Universe Image Credit & Copyright: Processing – Jean-Baptiste Auroux, Data – Mike Selby Explanation: Barred spiral galaxy NGC 1365 is truly a majestic island universe some 200,000 light-years across. Located a mere 60 million light-years away toward the faint but heated constellation Fornax, NGC 1365 is a dominant member of the well-studied Fornax Cluster of galaxies. This sharp color image shows the intense, reddish star forming regions near the ends of the galaxy’s central bar and along its spiral arms. Seen in fine detail, obscuring dust lanes cut across the galaxy’s bright core. At the core lies a supermassive black hole. Astronomers think NGC 1365’s prominent bar plays a crucial role in the galaxy’s evolution, drawing gas and dust into…

相机镜头里的猎户座升起

相机镜头里的猎户座升起

BySamuel Chan

2024年1月31日 Camera Orion Rising Image Credit & Copyright: Marcin Ślipko Explanation: What does Orion rising look like to a camera? During this time of the year, the famous constellation is visible to the southeast just after sunset. From most Earthly locations, Orion’s familiar star pattern, highlighted by the three-stars-in-a-row belt stars, rises sideways. An entire section of the night sky that includes Orion was photographed rising above Śnieżka, a mountain on the border between Poland and the Czech Republic. The long duration exposure sequence brings up many faint features including the Orion and Flame Nebulas, both encompassed by the curving Barnard’s Loop. The featured wide-angle camera composite also captured night sky icons including the blue Pleiades star cluster at the image top and the red…