A flash of lightning, and then—something else. High above a storm, a crimson figure blinks in and out of existence. If you see it, you are a lucky witness of a sprite, one of the least-understood electrical phenomena in Earth’s upper atmosphere.
Sprites occur at some 50 miles (80 kilometers) altitude, high above thunderstorms. They appear moments after a lightning strike – a sudden reddish flash that can take a range of shapes, often combining diffuse plumes and bright, spiny tendrils. Some sprites tend to dance over the storms, turning on and off one after another. Many questions about how and why they form remain unanswered. Sprites are the most frequently observed type of Transient Luminous Events (TLEs); TLEs can take a variety of fanciful shapes with equally fanciful names.
This image is the NASA Science Calendar Image of the Month for December 2025. Learn more about sprites and download this photo to use as a wallpaper on your phone or computer.
Text credit: Miles Hatfield
Image credit: Nicolas Escurat
一道闪电过后，天空中——某个地方——另一种光亮闪现。雷暴高空之上，一个深红色的身影忽明忽灭。如果你恰好看见它，那你就幸运地目睹了红色精灵——地球高层大气中最难以理解的电现象之一。
红色精灵发生在约50英里（80公里）的高度，远高于雷暴云顶。它们通常在一次闪电过后瞬间出现，以突如其来的红色闪光呈现，形态多样，常由弥散的羽状结构与亮度较强的针状触须组合而成。有些精灵像是在雷暴上空跳舞，彼此接连亮起与熄灭。关于它们如何形成、为何出现，仍有许多科学未解之谜。红色精灵是最常被观测到的瞬态发光事件（TLE）类型，而TLE还包括许多形状奇特、名称同样奇特的发光现象。
这张图像是NASA科学日历2025年12月的月度图像。你可以进一步了解红色精灵，并下载此图作为手机或电脑壁纸。
文字来源: Miles Hatfield
图片来源: Nicolas Escurat
