冰岛瀑布上空的彩虹极光

2023年12月27日

Rainbow Aurora over Icelandic Waterfall
Image Credit & Copyright: Stefano Pellegrini

Explanation: Yes, but can your aurora do this? First, yes, auroras can look like rainbows even though they are completely different phenomena. Auroras are caused by Sun-created particles being channeled into Earth’s atmosphere by Earth’s magnetic field, and create colors by exciting atoms at different heights. Conversely, rainbows are created by sunlight backscattering off falling raindrops, and different colors are refracted by slightly different angles. Unfortunately, auroras can’t create waterfalls, but if you plan well and are lucky enough, you can photograph them together. The featured picture is composed of several images taken on the same night last month near the Skógafoss waterfall in Iceland. The planning centered on capturing the central band of our Milky Way galaxy over the picturesque cascade. By luck, a spectacular aurora soon appeared just below the curving arch of the Milky Way. Far in the background, the Pleiades star cluster and the Andromeda galaxy can be found.

Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)

Tomorrow’s picture: open space

冰岛瀑布上空的彩虹极光
影像提供与版权: Stefano Pellegrini

说明: 你看到的极光有这么精采吗？首先，极光的外观的确可以很像彩虹，尽管它们是完全不同的现象。极光是源自太阳的粒子，在地球磁场的导引下进入地球的大气层，然后激发不同高度的原子发光。而彩虹则是阳光从滴落的雨滴反向散射所形成的，不同的色光会从略微不同的角度折射出来。很遗憾的是，极光无法产生瀑布，但如果你计画周全，而且运气够好的话，倒是可以让它们一同入镜。这张主题影像，是由上个月的某个夜晚，摄于冰岛斯科加瀑布附近的数张照片组合而成。这项拍摄计画的重点，是要捕捉悬在美丽的瀑布上空的银河系中央盘面。幸运的是，壮观的极光很快就出现在银河拱弧的下方。除此之外，在遥远的背景中，还可见到昴宿星团和仙女星系。（Pleiades 昴宿星团; Andromeda galaxy 仙女星系）