The path of the earth around the sun is an elliptical shaped orbit. But it should be noted that the exact path of the planet changes slightly over time. These changes in orbit can affect certain natural events on the planet, like weather and climate.
Description of Orbit
The average distance from Earth to the sun is 93 million miles. The greatest distance is 94.5 million miles, which occurs every year around July 4. The shortest distance is 91.5 million miles, which occurs around Jan. 3 of each year.
The Milankovitch Theory proposes that there are three types of variations within Earth's orbit that could possibly affect the climate in some sort of way. Milutin Milankovitch, a Yugoslavian astronomer, proposed that these changes have already been occurring on Earth for millions of years.
Change in the shape of Earth's orbit is called eccentricity. This change could also affect the climate in different parts of the world over a long period of time.
Axial Procession of the Equinoxes
Bulges in the spherical shape of Earth causes the planet to wobble on its axial plane as it spins and rotates around the sun. This causes slight changes in the observation of celestial bodies from Earth's surface, which is sometimes referred to as the precession of the equinoxes.
Milankovitch also proposed that a change in the tilt of the earth's axis could act to affect climate. This concept is called obliquity. In general, Milankovitch theories are applied toward understanding the advance and retreat of the Ice Ages that have occurred in the past.