In early July each year, the Earth’s elliptical orbit around the sun brings it to its farthest position from our solar system’s scintillating ball of gas.
The event this year, called aphelion, occurred on July 3, and an Australian photographer put together this time-lapse image of the aphelion sun rising over Brisbane, Australia, to recognize the occasion.
The seasons on Earth have little to do with the Earth’s distance from the sun but have nearly everything to do with the Earth’s 23-degree tilt, which scientists elegantly term the “obliquity of the ecliptic,” as either the northern or southern hemisphere spends half the year leaning in closer to the sun’s selflessly-giving warmth.
The “day of the most distant” sun, then, occurs during the southern hemisphere’s winter, when American’s are spreading out their beach towels — typically right before or after the July Fourth fireworks.
At our farthest from the sun, Earth is about 94.5 million miles away. The opposite of aphelion, perihelion, occurs in early January each year, and on average that New Year’s close-up bring us about 91.5 million miles from the sun. This difference in distance, gained from July to January, represents a six percent increase in the amount of solar radiation washing over our planet.
Although many of Earth’s denizens may presently feel otherwise, geologically speaking, it’s an ideal time to be an Earthling. The relatively mild elliptical shape of Earth’s orbit results in relatively temperate summer and winter conditions, allowing for life to flourish on most of Earth’s surface.
However, scientists believe that the Earth’s elliptical orbit changes in around 100,000-year cycles, called Milankovitch Cycles, sometimes becoming more oval-like and resulting in more extreme aphelion and perihelion events. In cases of high eccentricity, the perihelion is suspected to inundate Earth with between 20 to 30 percent more sunlight, a dose of radiation that would dramatically change Earth’s climate.
Fortunately, for all the species that inhabit this fair rock today, these closest and farthest away passes have a negligible effect, and we can carry on our simple existence, many of us ignorant that aphelion is even occurring.