Obliquity- describes how tilted a planet’s axis is (Fig. 3 shows the obliquity of eight planets, plus Pluto which is labeled as a planet). The tilt of the Earth is ultimately what allows for the existence of seasons, since the Northern Hemisphere is pointed toward the sun in the boreal summer, and away from the sun in the boreal winter.
INFO SHEET - Astronomical cycles - Ice caps have come and gone over the Earth’s surface for many millions of years. What has caused the cyclical warming and cooling of our planet? In the 1920s and 1930s, Milutin Milankovitch, a geophysicist, showed that the amount of heat received from the sun varied, and that this was related to cyclical changes in the Earth’s orbit. Further, this variation was linked to whether the Earth was in a glacial (colder) or interglacial (warmer) period.
Milutin Milanković - Scientists have not been able to disprove The Milankovitch Cycles theory, which describes the collective effects of change in the Earth's movements (e.g., axial tilt, variation in the elliptical orbit), which strongly influence climatic patterns on Earth over thousands of years.