Overview

• Earth reaches perihelion today, its closest point to the sun in its annual elliptical orbit, at a distance of about 91 million miles (147 million kilometers).
• The tilt of Earth's axis, not its distance from the sun, is responsible for seasonal changes, resulting in winter for the Northern Hemisphere and summer for the Southern Hemisphere.
• Perihelion slightly increases the amount of solar energy Earth receives, but this has minimal impact on global temperatures due to the distribution of land and ocean between hemispheres.
• Earth's orbit affects the length of seasons, with the Northern Hemisphere experiencing a shorter winter and longer summer due to the planet's faster orbital speed near perihelion.
• The phenomenon of perihelion was first explained by Johannes Kepler in the 17th century, who discovered that planets orbit the sun in ellipses, not perfect circles.