We have day and night because the Earth turns around. It takes one day for the Earth to turn around once.

DayNightBristol

The Earth turning makes day and night. In 24 hours the Earth turns round once. When we are facing the Sun it is day. When we face away it is night.

Earth at Night: The Black Marble. NASA-NOAA Suomi NPP satellite reveals new views of Earth at night. In daylight Earth is all land, oceans and clouds. But the night is electric.

Awesome video about Day & Night created by Reynaldo D Fernández. Pretty cool! Play it! Enjoy it!