National Geographic: With the United States in the clutches of a heat wave that is spurring deadly wildfires across the Southwest, it might feel like the sun is punishingly close right now. Actually the exact opposite is true: Earth will be farther from the sun on Friday, July 5, than on any other day this year.
That's because the orbits of all the planets in our solar system-including Earth's-are elliptical, as opposed to circular. The phenomenon was first explained in mathematical detail by the 17th-century German...