夜光云与NEOWISE彗星

夜光云与NEOWISE彗星

ByNASA中文

2020年7月9日 Noctilucent Clouds and Comet NEOWISE Image Credit & Copyright: Emmanuel Paoly Explanation: These silvery blue waves washing over a tree-lined horizon in the eastern French Alps are noctilucent clouds. From high in planet Earth’s mesosphere, they reflect sunlight in this predawn skyscape taken on July 8. This summer, the night-shining clouds are not new to the northern high-latitudes. Comet NEOWISE is though. Also known as C/2020 F3, the comet was discovered in March by the Earth-orbiting Near Earth Object Wide-field Infrared Survey Explorer (NEOWISE) satellite. It’s now emerging in morning twilight only just visible to the unaided eye from a clear location above the northeastern horizon. Tomorrow’s picture: pixels in space 光云与NEOWISE彗星 图像提供与版权：Emmanuel Paoly 说明：这些摄于法国东阿尔卑斯山，看似在冲击有成列绿树的地平线之银蓝波浪，其实是夜光云。在7月8日的清晨天空中，这些云在地球的中气层里反射阳光。而在今年的夏季，夜光云是北半球高纬度地区的常客。不过，刚在今年的3月，由绕行地球的广视野红外巡天卫星（NEOWISE）发现的NEOWISE彗星，则是如假包换的新访客。目前从视野广阔的地点，在东北地平线上方的曙光中，肉眼隐约可见到NEOWISE彗星。 明日的图片：pixels in space

中气层的红色精灵

中气层的红色精灵

ByNASA中文

2020年7月4日 Meeting in the Mesosphere Image Credit & Copyright: Stephane Vetter (TWAN, Nuits sacrees) Explanation: A sensitive video camera on a summit of the Vosges mountains in France captured these surprising fireworks above a distant horizon on June 26. Generated over intense thunderstorms, this one about 260 kilometers away, the brief and mysterious flashes have come to be known as red sprites. The transient luminous events are caused by electrical breakdown at altitudes of 50 to 100 kilometers. That puts them in the mesophere, the coldest layer of planet Earth’s atmosphere. The glow beneath the sprites is from more familiar lighting though, below the storm clouds. But on the right, the video frames have captured another summertime apparition from the mesophere. The silvery veins of…

夜光云

夜光云

ByNASA中文

2020 June 19 The Veins of Heaven Image Credit & Copyright: Ruslan Merzlyakov (RMS Photography) Explanation: Transfusing sunlight through a darkened sky, this beautiful display of noctilucent clouds was captured earlier this week, reflected in calm waters from Nykobing Mors, Denmark. From the edge of space, about 80 kilometers above Earth’s surface, the icy clouds themselves still reflect sunlight, though the Sun is below the horizon as seen from the ground. Usually spotted at high latitudes in summer months the night shining clouds have made an early appearance this year as northern nights grow short. Also known as polar mesopheric clouds they are understood to form as water vapor driven into the cold upper atmosphere condenses on the fine dust particles supplied by disintegrating meteors…