在平流层所见的北极光
2024年1月18日
Northern Lights from the Stratosphere
Image Credit & Copyright: Ralf Rohner
Explanation: Northern lights shine in this night skyview from planet Earth’s stratosphere, captured on January 15. The single, 5 second exposure was made with a hand-held camera on board an aircraft above Winnipeg, Canada. During the exposure, terrestrial lights below leave colorful trails along the direction of motion of the speeding aircraft. Above the more distant horizon, energetic particles accelerated along Earth’s magnetic field at the planet’s polar regions excite atomic oxygen to create the shimmering display of Aurora Borealis. The aurora’s characteristic greenish hue is generated at altitudes of 100-300 kilometers and red at even higher altitudes and lower atmospheric densities. The luminous glow of faint stars along the plane of our Milky Way galaxy arcs through the night, while the Andromeda galaxy extends this northern skyview to extragalactic space. A diffuse hint of Andromeda, the closest large spiral to the Milky Way, can just be seen to the upper left.
Tomorrow’s picture: shortest day in the Solar System
在平流层所见的北极光
影像提供与版权: Ralf Rohner
说明: 1月15日见于地球平流层的这片景观里，北极光在夜空中绽放光芒。这张5秒长曝光影像，是用手持的相机摄于飞越加拿大温尼伯市上空的飞机上。在曝光的期间，下方地面的灯火沿着飞机高速飞行的方向，曳出了五颜六色的迹线。在远方地平线的上方，受到极区地球磁场加速的高能粒子，则激发氧原子发出摇曳的北极光。极光特有的绿色辐射，起源于100-300公里的高空，而泛红的辐射则是来自大气密度更低的更上方空间。此外，银河盘面恒星散发的昏暗带状晕光，蜿蜒划过夜空，而仙女大星系更让这片北天的景观深及银河系外头的空间。这个离银河系最近的大星系，其弥漫身影隐约出现在左上方。
so beautiful