As we move through the year, different portions of the Earth receive direct sunlight. As a result, sometimes the North Pole tilts toward the Sun (as in June) and occasionally the South Pole tilts toward the Sun (like in December). As a result, the seasons. The angle at which the Earth's axis forms with respect to the orbit of the Sun around it is called its tilt. The Earth's orbit is elliptical, not circular; thus, it has an inclination with respect to the plane of the ecliptic, the path that the Earth follows as it orbits the Sun. This means that at any given time, some parts of the planet are in darkness while others are exposed to light from the Sun. The tilt of the Earth's axis causes differences in climate between the northern and southern hemispheres. During part of each year, most of Northern Europe is in daylight, but much of Australia is in darkness. In contrast, during part of each year, most of Australia is in daylight, but much of Northern Europe is in darkness. The tilt of the Earth's axis is one of the main factors governing the length of the day and seasonality of climate on Earth. Long before humans arrived on the scene, natural phenomena such as solar eclipses and volcanic eruptions caused by movements of the Earth's core led to changes in the amount of sunlight reaching various regions of the planet. These changes in turn affected the temperature and climate there.