While the blistering summer heat may make it hard to believe, today, July 5, the Sun was as far away from Earth as possible for the year.
Wildfires in Arizona and record-breaking temperatures across much of the Western United States might make it feel like the Sun is a next-door neighbor right now, but the elliptical orbit of the planets around the Sun means that every year the Earth will have a day like today when its farthest away from the Sun (the aphelion) and a point where it's closest, called the perihelion.
The official aphelion occurred Friday at 10:46 a.m. EDT when Earth was 94,508,959 miles (152,097,426 kilometers) from the Sun. The perihelion occurred this year on January 1 at 11:39 p.m. EDT, when Earth was 91,402,559 miles (147,098,161 kilometers) from the Sun, according to National Geographic.
Despite Earth's elliptical orbit around the Sun, the dates of the aphelion and perihelion lack symmetry on the calendar. The aphelion occurs between July 2 and July 6; the perihelion occurs between Jan. 1 to Jan. 5.
"The difference in dates is due more to the fact that the time it takes the Earth to complete one full orbit of the Sun is not an integer number of days, so the exact times of perihelion and aphelion vary from one year to the next," Mark Hammergren, an astronomer at the Adler Planetarium in Chicago, told National Geographic.
Today, when the Earth is farthest from the Sun, New York City had a forecast high temperature of 92 degrees Fahrenheit (33.3 C), Las Vegas at 108 F (42.2 C) and Houston at 93 F (33.8 C). But hot weather doesn't relate to Earth's distance from the Sun, it relates to the tilt of the planet towards the Sun. The 23.5-degree tilt of the Earth's axis determines whether the Sun's rays strike us at a low angle or more directly. Heat received in any part of the world depends on the length of daylight and the angle of the Sun above the horizon.
For instance, in Chicago the latitude of the city brings nearly direct Sun exposure on the summer solstice, bringing the city about three times as much Sun exposure than during the winter solstice, according to Space.com.