火流星与星空

2021年8月19日

Bright Meteor, Starry Sky
Image Credit & Copyright: Miguel Claro (TWAN, Dark Sky Alqueva)

Explanation: Plowing through Earth’s atmosphere at 60 kilometers per second, this bright perseid meteor streaks along a starry Milky Way. Captured in dark Portugal skies on August 12, it moves right to left through the frame. Its colorful trail starts near Deneb (alpha Cygni) and ends near Altair (alpha Aquilae), stars of the northern summer triangle. In fact this perseid meteor very briefly outshines both, two of the brightest stars in planet Earth’s night. The trail’s initial greenish glow is typical of the bright perseid shower meteors. The grains of cosmic sand, swept up dust from periodic comet Swift-Tuttle, are moving fast enough to excite the characteristic green emission of atomic oxygen at altitudes of 100 kilometers or so before vaporizing in an incandescent flash.

Notable APOD Image Submissions: Perseid Meteor Shower 2021

Tomorrow’s picture: Three Dark Nights

火流星与星空
影像提供与版权: Miguel Claro (TWAN, Dark Sky Alqueva)

说明: 以每秒60公里高速穿过地球大气的这颗英仙座流星，沿着满是繁星的银河飞掠，留下一道明亮的流星痕。8月12日闪现在葡萄牙幽暗夜空中的这颗流星，从右向左掠过视野。它多彩的流星痕，起于天津四 （天鹅α星）、止于牛郎（天鹰α星）这二颗夏三角成员星的附近。在最明亮的极短暂期间，这颗英仙座流星亮度胜过这二颗地球夜空的亮星。这道流星痕初始的泛绿辉光，是英仙座流星雨的火流星之典型特征。来自周期彗星史威福·塔托的这群宇宙沙粒，穿行的速率高到可以激发100公里高空附近的氧原子，让它在完全汽化之前发出特征性的明亮绿光辐射。

值得注意的提交给APOD的图像：2021年英仙座流星雨

明日的图片: Three Dark Nights