Earth Farthest From Sun on Fourth of July—So Why So Hot?
Earth will be at its maximum distance from the sun Wednesday—but Northern Hemisphere dwellers shouldn't expect relief from the summer heat.
That's because the orbits of all the planets in our solar system—including Earth's—are not perfectly circular, a phenomenon that was first explained in mathematical detail by the 17th-century German astronomer Johannes Kepler.
Kepler "figured out the orbits of the planets were elliptical in shape and that the sun was offset from the center," explained Mark Hammergren, an astronomer at the Adler Planetarium in Chicago, Illinois.
Earth's elliptical orbit means there will be a point each year when the planet is closest to the sun, called perihelion, and a point when it is farthest away, known as aphelion.
(Related: "Sun Headed Into Hibernation, Solar Studies Predict.")
On July 4 at 11 p.m. ET our planet will be at aphelion—94,511,923 miles (152,102,196 kilometers) from the sun.