暮光里的卫星

暮光里的卫星

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2022年2月4日 Moons at Twilight Image Credit & Copyright: Robert Fedez Explanation: Even though Jupiter was the only planet visible in the evening sky on February 2, it shared the twilight above the western horizon with the Solar System’s brightest moons. In a single exposure made just after sunset, the Solar System’s ruling gas giant is at the upper right in this telephoto field-of-view from Cancun, Mexico. The snapshot also captures our fair planet’s own natural satellite in its young crescent phase. The Moon’s disk looms large, its familiar face illuminated mostly by earthshine. But the four points of light lined-up with Jupiter are Jupiter’s own large Galilean moons. Top to bottom are Ganymede, [Jupiter], Io, Europa, and Callisto. Ganymede, Io, and Callisto are physically larger…

金星与月亮

金星与月亮

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2022年2月3日 Embraced by Sunlight Image Credit & Copyright: Juan Luis Cánovas Pérez Explanation: Even though Venus (left) was the brightest planet in the sky it was less than 1/30th the apparent size of the Moon on January 29. But as both rose before the Sun they shared a crescent phase. For a moment their visible disks were each about 12 percent illuminated as they stood above the southeastern horizon. The similar sunlit crescents were captured in these two separate images. Made at different magnifications, each panel is a composite of stacked video frames taken with a small telescope. Venus goes through a range of phases like the Moon as the inner planet wanders from evening sky to morning sky and back again with a period…

狐獴阵列在无线电波段所拍摄的银河中心

狐獴阵列在无线电波段所拍摄的银河中心

ByNASA中文

2022年2月2日 The Galactic Center in Radio from MeerKAT Image Credit: Ian Heywood (Oxford U.), SARAO; Color Processing: Juan Carlos Munoz-Mateos (ESO) Explanation: What’s happening at the center of our galaxy? It’s hard to tell with optical telescopes since visible light is blocked by intervening interstellar dust. In other bands of light, though, such as radio, the galactic center can be imaged and shows itself to be quite an interesting and active place. The featured picture shows the latest image of our Milky Way’s center by the MeerKAT array of 64 radio dishes in South Africa. Spanning four times the angular size of the Moon (2 degrees), the image is impressively vast, deep, and detailed. Many known sources are shown in clear detail, including many with…

2022年的月相

2022年的月相

ByNASA中文

2022年2月1日 Moon Phases 2022 Video Credit: Data: Lunar Reconnaissance Orbiter ; Animation: NASA’s Scientific Visualization Studio; Music: Build the Future (Universal Production Music), Alexander Hitchens Explanation: What will the Moon phase be on your birthday this year? It is hard to predict because the Moon’s appearance changes nightly. As the Moon orbits the Earth, the half illuminated by the Sun first becomes increasingly visible, then decreasingly visible. The featured video animates images and altitude data taken by NASA’s Moon-orbiting Lunar Reconnaissance Orbiter to show all 12 lunations that appear this year, 2022 — as seen from Earth’s northern (southern) hemisphere. A single lunation describes one full cycle of our Moon, including all of its phases. A full lunation takes about 29.5 days, just under a…

船底座大星云的北缘

船底座大星云的北缘

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2022年1月31日 Carina Nebula North Image Credit & Copyright: Roberto Colombari Explanation: The Great Carina Nebula is home to strange stars and iconic nebulas. Named for its home constellation, the huge star-forming region is larger and brighter than the Great Orion Nebula but less well known because it is so far south — and because so much of humanity lives so far north. The featured image shows in great detail the northern-most part of the Carina Nebula. Visible nebulas include the semi-circular filaments surrounding the active star Wolf-Rayet 23 (WR23) on the far left. Just left of center is the Gabriela Mistral Nebula consisting of an emission nebula of glowing gas (IC 2599) surrounding the small open cluster of stars (NGC 3324). Above the image center…

SOHO卫星拍摄的日珥

SOHO卫星拍摄的日珥

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2022年1月30日 A Solar Prominence from SOHO Image Credit: NASA, ESA, SOHO-EIT Consortium Explanation: How can gas float above the Sun? Twisted magnetic fields arching from the solar surface can trap ionized gas, suspending it in huge looping structures. These majestic plasma arches are seen as prominences above the solar limb. In 1999, this dramatic and detailed image was recorded by the Extreme ultraviolet Image Telescope (EIT) on board the space-based SOHO observatory in the light emitted by ionized Helium. It shows hot plasma escaping into space as a fiery prominence breaks free from magnetic confinement a hundred thousand kilometers above the Sun. These awesome events bear watching as they can affect communications and power systems over 100 million kilometers away on planet Earth. In late…

天炉座星系团

天炉座星系团

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2022年1月29日 The Fornax Cluster of Galaxies Image Credit & Copyright: Marco Lorenzi, Angus Lau, Tommy Tse Explanation: Named for the southern constellation toward which most of its galaxies can be found, the Fornax Cluster is one of the closest clusters of galaxies. About 62 million light-years away, it is almost 20 times more distant than our neighboring Andromeda Galaxy, and only about 10 percent farther than the better known and more populated Virgo Galaxy Cluster. Seen across this two degree wide field-of-view, almost every yellowish splotch on the image is an elliptical galaxy in the Fornax cluster. Elliptical galaxies NGC 1399 and NGC 1404 are the dominant, bright cluster members toward the upper left (but not the spiky foreground stars). A standout barred spiral galaxy…

月球西缘的东海

月球西缘的东海

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2022年1月28日 Western Moon, Eastern Sea Image Credit & Copyright: Tom Glenn Explanation: The Mare Orientale, Latin for Eastern Sea, is one of the most striking large scale lunar features. The youngest of the large lunar impact basins it’s very difficult to see from an earthbound perspective. Still, taken during a period of favorable tilt, or libration of the lunar nearside, the Eastern Sea can be found near top center in this sharp telescopic view, extremely foreshortened along the Moon’s western edge. Formed by the impact of an asteroid over 3 billion years ago and nearly 1000 kilometers across, the impact basin’s concentric circular features, ripples in the lunar crust, are a little easier to spot in spacecraft images of the Moon, though. So why is…

猎户座星云之南

猎户座星云之南

ByNASA中文

2022年1月27日 South of Orion Image Credit & Copyright: Vikas Chander Explanation: South of the large star-forming region known as the Orion Nebula, lies bright blue reflection nebula NGC 1999. At the edge of the Orion molecular cloud complex some 1,500 light-years distant, NGC 1999’s illumination is provided by the embedded variable star V380 Orionis. The nebula is marked with a dark sideways T-shape at center right in this telescopic vista that spans about two full moons on the sky. Its dark shape was once assumed to be an obscuring dust cloud seen in silhouette. But infrared data suggest the shape is likely a hole blown through the nebula itself by energetic young stars. In fact, this region abounds with energetic young stars producing jets and…

心宿二附近的恒星、尘埃和气体

心宿二附近的恒星、尘埃和气体

ByNASA中文

2022年1月26日 Stars, Dust, and Gas Near Antares Image Credit & Copyright: Mario Cogo (Galax Lux) Explanation: Why is the sky near Antares and Rho Ophiuchi so dusty yet colorful? The colors result from a mixture of objects and processes. Fine dust — illuminated from the front by starlight — produces blue reflection nebulae. Gaseous clouds whose atoms are excited by ultraviolet starlight produce reddish emission nebulae. Backlit dust clouds block starlight and so appear dark. Antares, a red supergiant and one of the brighter stars in the night sky, lights up the yellow-red clouds on the lower right of the featured image. The Rho Ophiuchi star system lies at the center of the blue reflection nebula on the top left. The distant globular cluster of…