Conjunction of Mercury and Venus above the Moon

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图注： From the observing deck at the European Southern Observatory’s Paranal site in Chile, in March 2008, astronomers captured a conjunction of celestial objects—a moment when two or more astronomical objects appear close together in the sky as seen from Earth. In this scene, the innermost planets Mercury and Venus appear aligned above the Moon, forming a pattern against the sky just before dawn. Although they are at very different distances from Earth, the geometry of their orbits brought them into almost the same line of sight, creating this beautiful cosmic alignment. In the image, the bright crescent Moon is visible low in the sky near the horizon, forming the most prominent object in the lower part of the scene. Just above the Moon, the brighter planet Venus can be seen, while Mercury, fainter and further from the horizon, appears nearby in the upper part of the image.
来源： ESO/Y. Beletsky
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词汇表: 合

授权许可： 知识共享许可协议 署名 4.0 国际 (CC BY 4.0) 知识共享许可协议 署名 4.0 国际 (CC BY 4.0) 图标

文件 ( 图像 2.43 MB)

Atmosphere of Venus

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图注： This image of Venus was captured in ultraviolet light by the Pioneer Venus Orbiter and highlights features of the planet’s thick atmosphere that are not visible in ordinary light. Venus has a dense, cloudy atmosphere composed mainly of carbon dioxide. In ultraviolet wavelengths, patterns in the upper cloud layers become visible, revealing swirling structures and bright and dark bands caused by differences in the composition and motion of the atmosphere. These ultraviolet features help scientists map wind patterns, atmospheric circulation, and cloud dynamics high above Venus’s surface. Unlike Earth’s atmosphere, which is relatively transparent in visible light, Venus’s atmosphere is so thick that no direct view of the surface is possible from space without special instruments. The extreme pressure and temperature near Venus’s surface are consequences of this dense gaseous envelope, making Venus a dramatic example of how different planetary atmospheres can be. This image demonstrates how observing a planet’s atmosphere in different wavelengths, such as ultraviolet, reveals details about its structure and behaviour.
来源： NASA
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词汇表: 大气层 , 金星

授权许可： 公共领域 公共领域 图标

文件 ( 图像 8.09 MB)

Mare Crisium - Sea of Crises

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图注： The image shows the lunar Mare Crisium, the “Sea of Crises,” as seen by NASA’s Lunar Reconnaissance Orbiter in 2015. The photo size is 750 × 750 km, about the size of Germany. Mare Crisium is located in the Moon’s Crisium basin, near the great Mare Tranquillitatis on the near side of the Moon. It is visible from Earth and is characterized by a relatively smooth and flat surface surrounded by cliffs and highlands. The basin that now contains the Mare Crisium was formed by a massive impact event likely during the Nectarian period approximately 3.9 billion years ago. During this time in lunar history, major basins including the Crisium basis were formed by large impact events. Later in lunar history, the basin was flooded by lava to form the dark and flat plain we see today. Its floor is about 1.8 kilometers below the typical lunar surface level. The study of lunar maria provides insights into the volcanic history and impact processes that have affected the Moon and other celestial objects.
来源： NASA, Lunar Reconnaissance Orbiter
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词汇表: 月球 , 月海
分类： 太阳系

授权许可： 公共领域 公共领域 图标

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ISS' view of nightly Japan

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图注： This nighttime photograph of Earth was taken from the International Space Station (ISS) by astronaut Scott Kelly in 2015 during Expedition 44. It captures the nation of Japan lit up after dark, with bright city lights tracing urban centers, major roadways, and densely populated regions. The view from orbit at night highlights how human activity shows up as patterns of light on Earth’s surface, with well-lit areas contrasting sharply against the surrounding darkness of rural regions and open water. Photographs like this highlight what “night” looks like from space — not just a lack of sunlight, but also a time when artificial light reveals the rhythms of human life across the globe. From hundreds of kilometers above the planet, the night side of Earth appears as a tapestry of glowing clusters and dark spaces, offering insight into population distribution, infrastructure, and how cities remain active long after sunset. The ISS’s low orbit allows astronauts to capture these detailed views of Earth after dark, helping us appreciate both natural and human elements of nighttime on our planet.
来源： NASA
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词汇表: 地球 , 夜

授权许可： 公共领域 公共领域 图标

文件 ( 图像 24.73 MB)

Detailed View of Charon, Moon of Pluto

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图注： Charon is the largest natural moon of the dwarf planet Pluto. This detailed image was taken by NASA’s New Horizons spacecraft in 2015 during its historic mission through the outer Solar System. Charon’s surface shows a fascinating mix of light and dark regions, including vast canyons, broad plains, and impact crater. With a diameter of about 1,200 kilometers, Charon is more than half the diameter of Pluto, making it unusually large compared to its parent body. Charon's mass is roughly 12% of that of Pluto. Because Pluto and Charon are so close in mass, the center of mass of the system (the point both Pluto and Charon orbit) is not within Pluto but between Pluto and Charon. This is in contrast to systems like the Earth and its Moon where the center of mass lies within the larger body, the Earth in this case. Scientists think the Pluto-Charon system may have formed by a collision of two objects that then separated and began to orbit each other. By studying Charon and the smaller moons that circle Pluto, astronomers gain insight into how moons form and how distant icy bodies evolve over billions of years.
来源： NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Alex Parker
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词汇表: 卫星 , 冥王星

授权许可： 公共领域 公共领域 图标

文件 ( 图像 2.88 MB)