Our Planet’s Elliptical Orbit

The Earth travels around the Sun in an ellipse, not a perfect circle. The average distance is about 93 million miles (149 million kilometers). Because the orbit is slightly elongated, the distance varies throughout the year.

During aphelion – the point farthest from the Sun – the Earth is roughly 94.5 million miles away. This occurs near July 4 each year. At perihelion – the closest approach – the distance shrinks to about 91.5 million miles, around January 3.

Milankovitch Cycles: The Climate Drivers

Astrophysicist Milutin Milankovitch identified three orbital parameters that, over tens of thousands to millions of years, modulate Earth’s climate:

• Eccentricity – the gradual change in the shape of the orbit, altering the Sun–Earth distance over time.
• Obliquity – the wobble in the tilt of Earth’s axis, influencing seasonal contrast.
• Precession – the slow shift in the orientation of Earth’s axis, affecting the timing of seasons.

These variations help explain the advance and retreat of ice ages and long‑term climate patterns.