萨丁尼亚岛的夜空

萨丁尼亚岛的夜空

ByNASA中文

2020年10月21日 A Night Sky Vista from Sardinia Image Credit & Copyright: Tomáš Slovinský Explanation: How many famous sky objects can you find in this image? The featured dark sky composite combines over 60 exposures spanning over 220 degrees to create a veritable menagerie of night sky wonders. Visible celestial icons include the Belt of Orion, the Orion Nebula, the Andromeda Galaxy, the California Nebula, and bright stars Sirius and Betelgeuse. You can verify that you found these, if you did, by checking an annotated version of the image. A bit harder, though, is finding Polaris and the Big Dipper. Also discernible are several meteors from the Quandrantids meteor shower, red and green airglow, and two friends of the astrophotographer. The picture was captured in January…

三尖峰上空的土星和木星

三尖峰上空的土星和木星

ByNASA中文

2020年10月20日 Saturn and Jupiter over Italian Peaks Image Credit & Copyright: Giorgia Hofer Explanation: Saturn and Jupiter are getting closer. Every night that you go out and check for the next two months, these two bright planets will be even closer together on the sky. Finally, in mid-December, a Great Conjunction will occur — when the two planets will appear only 0.1 degrees apart — just one fifth the angular diameter of the full Moon. And this isn’t just any Great Conjunction — Saturn (left) and Jupiter (right) haven’t been this close since 1623, and won’t be nearly this close again until 2080. This celestial event is quite easy to see — already the two planets are easily visible toward the southwest just after sunset…

飞越木星的大红斑

飞越木星的大红斑

ByNASA中文

2020年10月19日 A Flight over Jupiter Near the Great Red Spot Image Credit: NASA/JPL-Caltech/SwRI/MSSS; Video Processing & License: Kevin M. Gill; Music: Vangelis Explanation: Are you willing to wait to see the largest and oldest known storm system in the Solar System? In the featured video, Jupiter’s Great Red Spot finally makes its appearance 2 minutes and 12 seconds into the 5-minute video. Before it arrives, you may find it pleasing to enjoy the continually changing view of the seemingly serene clouds of Jupiter, possibly with your lights low and sound up. The 41 frames that compose the video were captured in June as the robotic Juno spacecraft was making a close pass over our Solar System’s largest planet. The time-lapse sequence actually occurred over four…

UGC 1810： 狂乱互扰星系的哈勃望远镜影像

UGC 1810： 狂乱互扰星系的哈勃望远镜影像

ByNASA中文

2020年10月18日 UGC 1810: Wildly Interacting Galaxy from Hubble Image Credit: NASA, ESA, Hubble, HLA; Processing & Copyright: Domingo Pestana Explanation: What’s happening to this spiral galaxy? Although details remain uncertain, it surely has to do with an ongoing battle with its smaller galactic neighbor. The featured galaxy is labelled UGC 1810 by itself, but together with its collisional partner is known as Arp 273. The overall shape of UGC 1810 — in particular its blue outer ring — is likely a result of wild and violent gravitational interactions. This ring’s blue color is caused by massive stars that are blue hot and have formed only in the past few million years. The inner galaxy appears older, redder, and threaded with cool filamentary dust. A few…

天鹅座的皂泡与眉月星云

天鹅座的皂泡与眉月星云

ByNASA中文

2020年10月17日 Cygnus: Bubble and Crescent Image Credit & Copyright: Wissam Ayoub Explanation: These clouds of gas and dust drift through rich star fields along the plane of our Milky Way Galaxy toward the high flying constellation Cygnus. Caught within the telescopic field of view are the Soap Bubble (lower left) and the Crescent Nebula (upper right). Both were formed at a final phase in the life of a star. Also known as NGC 6888, the Crescent was shaped as its bright, central massive Wolf-Rayet star, WR 136, shed its outer envelope in a strong stellar wind. Burning through fuel at a prodigious rate, WR 136 is near the end of a short life that should finish in a spectacular supernova explosion. Discovered in 2013, the…

行星状星云Abell 78

行星状星云Abell 78

ByNASA中文

2020年10月16日 Planetary Nebula Abell 78 Image Credit & Copyright: Bernhard Hubl Explanation: Planetary nebula Abell 78 stands out in this colorful telescopic skyscape. In fact the colors of the spiky Milky Way stars depend on their surface temperatures, both cooler (yellowish) and hotter (bluish) than the Sun. But Abell 78 shines by the characteristic emission of ionized atoms in the tenuous shroud of material shrugged off from an intensely hot central star. The atoms are ionized, their electrons stripped away, by the central star’s energetic but otherwise invisible ultraviolet light. The visible blue-green glow of loops and filaments in the nebula’s central region corresponds to emission from doubly ionized oxygen atoms, surrounded by strong red emission from ionized hydrogen. Some 5,000 light-years distant toward the…

飞马座的星系

飞马座的星系

ByNASA中文

2020年10月15日 Galaxies in Pegasus Image Credit & Copyright: Robert Eder Explanation: This sharp telescopic view reveals galaxies scattered beyond the stars of the Milky Way, at the northern boundary of the high-flying constellation Pegasus. Prominent at the upper right is NGC 7331. A mere 50 million light-years away, the large spiral is one of the brighter galaxies not included in Charles Messier’s famous 18th century catalog. The disturbed looking group of galaxies at the lower left is well-known as Stephan’s Quintet. About 300 million light-years distant, the quintet dramatically illustrates a multiple galaxy collision, its powerful, ongoing interactions posed for a brief cosmic snapshot. On the sky, the quintet and NGC 7331 are separated by about half a degree. Tomorrow’s picture: pixels in space 飞马座的星系…

心宿增四星云的美丽云气

心宿增四星云的美丽云气

ByNASA中文

2020年10月14日 The Colorful Clouds of Rho Ophiuchi Image Credit & Copyright: Amir H. Abolfath Explanation: The many spectacular colors of the Rho Ophiuchi (oh’-fee-yu-kee) clouds highlight the many processes that occur there. The blue regions shine primarily by reflected light. Blue light from the Rho Ophiuchi star system and nearby stars reflects more efficiently off this portion of the nebula than red light. The Earth’s daytime sky appears blue for the same reason. The red and yellow regions shine primarily because of emission from the nebula’s atomic and molecular gas. Light from nearby blue stars – more energetic than the bright star Antares – knocks electrons away from the gas, which then shines when the electrons recombine with the gas. The dark brown regions are…

火星、昴宿星团与仙女座星系

火星、昴宿星团与仙女座星系

ByNASA中文

2020年10月13日 Mars, Pleiades, and Andromeda over Stone Lions Image Credit & Copyright: Cem Özkeser Explanation: Three very different — and very famous — objects were all captured in a single frame last month. On the upper left is the bright blue Pleiades, perhaps the most famous cluster of stars on the night sky. The Pleiades (M45) is about 450 light years away and easily found a few degrees from Orion. On the upper right is the expansive Andromeda Galaxy, perhaps the most famous galaxy — external to our own — on the night sky. Andromeda (M31) is one of few objects visible to the unaided eye where you can see light that is millions of years old. In the middle is bright red Mars, perhaps…

降落贝努小行星

降落贝努小行星

ByNASA中文

2020年10月12日 Descending Toward Asteroid Bennu Video Credit: NASA, OSIRIS-REx, NASA’s Scientific Visualization Studio; Data: NASA, U. Arizona, CSA, York U., MDA Explanation: What would it be like to land on an asteroid? Although no human has yet done it, NASA’s robotic OSIRIS-REx spacecraft is scheduled to attempt to touch the surface of asteroid 101955 Bennu next week. The goal is to collect a sample from the nearby minor planet for return to Earth for a detailed analysis in 2023. The featured video shows what it looks like to descend toward the 500-meter diamond-shaped asteroid, based on a digital map of Bennu’s rocky surface constructed from image and surface data taken by OSIRIS-REx over the past 1.5 years. The video begins by showing a rapidly spinning…