Question

What does the speaker talk about the sun ? How does he know whether it is day or night

Answer 1

Wait I'm confused explain

Answer 2

I realy need to help you but unfortunately you did not specify the type and name of the text of the speaker. Please specify this, provisionaly I can provide you the common indicators that show wether it is day or night.  During the day there is the sun and during the night the moon.  Hope this answer helps you out.