仙女大星系周围的云气

仙女大星系周围的云气

ByNASA中文

2022年10月24日 Clouds Around Galaxy Andromeda Image Credit & Copyright: Andrew Fryhover Explanation: What are those red clouds surrounding the Andromeda galaxy? This galaxy, M31, is often imaged by planet Earth-based astronomers. As the nearest large spiral galaxy, it is a familiar sight with dark dust lanes, bright yellowish core, and spiral arms traced by clouds of bright blue stars. A mosaic of well-exposed broad and narrow-band image data, this deep portrait of our neighboring island universe offers strikingly unfamiliar features though, faint reddish clouds of glowing ionized hydrogen gas in the same wide field of view. Most of the ionized hydrogen clouds surely lie in the foreground of the scene, well within our Milky Way Galaxy. They are likely associated with the pervasive, dusty interstellar…

南天的仙女座星系

南天的仙女座星系

ByNASA中文

2022年10月21日 Andromeda in Southern Skies Image Credit & Copyright: Ian Griffin (Otago Museum) Explanation: Looking north from southern New Zealand, the Andromeda Galaxy never gets more than about five degrees above the horizon. As spring comes to the southern hemisphere, in late September Andromeda is highest in the sky around midnight though. In a single 30 second exposure this telephoto image tracked the stars to capture the closest large spiral galaxy from Mount John Observatory as it climbed just over the rugged peaks of the south island’s Southern Alps. In the foreground, stars are reflected in the still waters of Lake Alexandrina. Also known as M31, the Andromeda Galaxy is one of the brightest objects in the Messier catalog, usually visible to the unaided eye…

星系前方的流星

星系前方的流星

ByNASA中文

2022年8月7日 Meteor before Galaxy Image Credit & Copyright: Fritz Helmut Hemmerich Explanation: What’s that green streak in front of the Andromeda galaxy? A meteor. While photographing the Andromeda galaxy in 2016, near the peak of the Perseid Meteor Shower, a small pebble from deep space crossed right in front of our Milky Way Galaxy’s far-distant companion. The small meteor took only a fraction of a second to pass through this 10-degree field. The meteor flared several times while braking violently upon entering Earth’s atmosphere. The green color was created, at least in part, by the meteor’s gas glowing as it vaporized. Although the exposure was timed to catch a Perseid meteor, the orientation of the imaged streak seems a better match to a meteor from…

银河系的末日：将与仙女座星系互撞

银河系的末日：将与仙女座星系互撞

ByNASA中文

2022年6月6日 Milky Way Galaxy Doomed: Collision with Andromeda Pending Image Credit: NASA, ESA, Z. Levay and R. van der Marel (STScI); T. Hallas; and A. Mellinger Explanation: Will our Milky Way Galaxy collide one day with its larger neighbor, the Andromeda Galaxy? Most likely, yes. Careful plotting of slight displacements of M31’s stars relative to background galaxies on recent Hubble Space Telescope images indicate that the center of M31 could be on a direct collision course with the center of our home galaxy. Still, the errors in sideways velocity appear sufficiently large to admit a good chance that the central parts of the two galaxies will miss, slightly, but will become close enough for their outer halos to become gravitationally entangled. Once that happens, the…

仙女座星系过去与未来的恒星

仙女座星系过去与未来的恒星

ByNASA中文

2022年5月23日 The Once and Future Stars of Andromeda Image Credit: NASA, NSF, NOAJ, Hubble, Subaru, Mayall, DSS, Spitzer; Processing & Copyright: Robert Gendler & Russell Croman Explanation: This picture of Andromeda shows not only where stars are now, but where stars will soon be. Of course, the big, beautiful Andromeda Galaxy, M31, is a spiral galaxy — and a mere 2.5 million light-years away. Both space-based and ground-based observatories have been here combined to produce this intriguing composite image of Andromeda, at wavelengths both inside and outside normally visible light. The visible light shows where M31’s stars are now — as highlighted in white and blue hues and imaged by the Hubble, Subaru, and Mayall telescopes. The infrared light shows where M31’s future stars will…

葡萄牙上空的恒星与行星

葡萄牙上空的恒星与行星

ByNASA中文

2022年4月18日 Stars and Planets over Portugal Image Credit & Copyright: Miguel Claro (TWAN, Dark Sky Alqueva) Explanation: The mission was to document night-flying birds — but it ended up also documenting a beautiful sky. The featured wide-angle mosaic was taken over the steppe golden fields in Mértola, Portugal in 2020. From such a dark location, an immediately-evident breathtaking glow arched over the night sky: the central band of our Milky Way galaxy. But this sky had much more. Thin clouds crossed the sky like golden ribbons. The planet Mars appeared on the far left, while the planets Saturn and Jupiter were also simultaneously visible — but on the opposite side of the sky, here seen on the far right. Near the top of the image…

夜空中的银河和黄道光

夜空中的银河和黄道光

ByNASA中文

2022年3月1日 Dueling Bands in the Night Image Credit & Copyright: Jeff Dai (TWAN) Explanation: What are these two bands in the sky? The more commonly seen band is the one on the right and is the central band of our Milky Way galaxy. Our Sun orbits in the disk of this spiral galaxy, so that from inside, this disk appears as a band of comparable brightness all the way around the sky. The Milky Way band can also be seen all year — if out away from city lights. The less commonly seem band, on the left, is zodiacal light — sunlight reflected from dust orbiting the Sun in our Solar System. Zodiacal light is brightest near the Sun and so is best seen just…

M31：仙女座星系

M31：仙女座星系

ByNASA中文

2022年1月19日 M31: The Andromeda Galaxy Image Credit: Subaru (NAOJ), Hubble (NASA/ESA), Mayall (NSF); Processing & Copyright: R. Gendler & R. Croman Explanation: The most distant object easily visible to the unaided eye is M31, the great Andromeda Galaxy. Even at some two and a half million light-years distant, this immense spiral galaxy — spanning over 200,000 light years — is visible, although as a faint, nebulous cloud in the constellation Andromeda. In contrast, a bright yellow nucleus, dark winding dust lanes, and expansive spiral arms dotted with blue star clusters and red nebulae, are recorded in this stunning telescopic image which combines data from orbiting Hubble with ground-based images from Subaru and Mayall. In only about 5 billion years, the Andromeda galaxy may be even…

M33：三角大星系

M33：三角大星系

ByNASA中文

2021年11月12日 M33: The Triangulum Galaxy Image Credit & Copyright: Bernard Miller Explanation: The small, northern constellation Triangulum harbors this magnificent face-on spiral galaxy, M33. Its popular names include the Pinwheel Galaxy or just the Triangulum Galaxy. M33 is over 50,000 light-years in diameter, third largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way. About 3 million light-years from the Milky Way, M33 is itself thought to be a satellite of the Andromeda Galaxy and astronomers in these two galaxies would likely have spectacular views of each other’s grand spiral star systems. As for the view from planet Earth, this sharp image shows off M33’s blue star clusters and pinkish star forming regions along the galaxy’s loosely wound…

好友之间的星系

好友之间的星系

ByNASA中文

2021年11月06日 The Galaxy Between Two Friends Image Credit & Copyright: Martin Lefranc Explanation: On an August night two friends enjoyed this view after a day’s hike on the Plateau d’Emparis in the French Alps. At 2400 meters altitude the sky was clear. Light from a setting moon illuminates the foreground captured in the simple vertical panorama of images. Along the plane of our Milky Way galaxy stars of Cassiopeia and Perseus shine along the panorama’s left edge. But seen as a faint cloud with a brighter core, the Andromeda galaxy, stands directly above the two friends in the night. The nearest large spiral galaxy, Andromeda is about 2.5 million light-years beyond the stars of the Milky Way. Adding to the evening’s shared extragalactic perspective, the…