What is the natural phenomenon of lightning running at night when you are old?

It's natural to thunder at night when you are old. Startling, called "awakening" in ancient times, is the third of the 24 solar terms. The two poems, "When people are old, why don't you save something to remind yourself that the lighting suddenly thunders at night", are from the Song Dynasty poet Zhang's "Thunder of Tomorrow Seen on the 14th of the First Month", which expresses the poet's feelings about the passage of time and his unique feelings about the solar terms. This poem expresses the helplessness of the passage of time and deep thinking about the changes of life by describing the shocking solar terms and the poet's inner feelings. At the same time, the poet also makes readers feel the unique breath and charm of the shocking solar terms through vivid pictures and sound descriptions.