The rotation of the earth causes day and night. The tilt of the earth's axis causes the amount of light that is shown on different parts of the earth. The earth's axis is always on a tilt. Thus causes the earth's equator to also be tilted. The earth's tilt always faces the north star. The earth's tilt effects the amount of sunlight received on earth. It can cause longer days, longer nights, equal day, and equal night.