The shadow

A scholar from a cold country lived in a hot country, but he found it difficult to adapt to the climate. In the daytime, his shadow became tiny: it really was too hot for him. So, he stayed at home and went out in the evening. As the temperature went down, the town came to life. One night, the scholar was woken by a mysterious and intriguing light. What was it? How could it be explained? That is what he would try to discover.