C336 Origin of white light

Arriving at the Mr. Ning's residence, I saw a western-era clock on the wall. The clock said eight o'clock sharp.

I thought it was already early in the morning, but after looking at the clock, I knew it was this time of day. No wonder he came to deliver food to me at that time of night, I thought it was midnight snack then, so it was because there was no light outside