Here comes the sun.
Earth on Tuesday made its closest approach to the sun, an annual celestial event that happens to occur at the start of the new year.
The planet follows an elliptical orbit around the sun, rather than a circular orbit. This means over the course of the roughly 365 days it takes Earth to complete one loop around its parent star, the planet swings through its closest point to the sun early in the year and then its farthest point months later.
Earth reached its closest point to the sun Tuesday at 1:52 a.m. EST, a configuration known as perihelion. Though mostly imperceptible, the planet is now roughly 3 million miles closer to the sun than when Earth reaches the farthest point in its orbit around the star.
This year, Earth will be furthest from the sun on July 4. That moment, called aphelion, will occur when the distance between the two celestial bodies stretches to more than 94.5 million miles.
At perihelion, Earth is roughly 91.4 million miles away from the sun. On average, the planet is separated from the sun by a distance of approximately 93 million miles.
The term perihelion comes from the ancient Greek "peri," which means "close," and "helios," meaning the sun. Conversely, aphelion comes from combining "apo," meaning "away from," with "helios." Each term is sometimes called an apsis, which refers to the nearest or farthest point between a celestial body and its host.
Though perihelion occurs during winter in the Northern Hemisphere and aphelion occurs during summer, Earth's elliptical orbit around the sun does not cause the seasons. Rather, the planet's tilt as it rotates on its axis drives the changes between winter, spring, summer and fall.
As such, winter descends on the Northern Hemisphere when that part of the planet is tilted away from the sun, and summer returns when the Northern Hemisphere is tilted toward the sun.
Perihelion typically occurs in early January and aphelion usually occurs in early July, but because Earth's orbit is slightly eccentric, those timings can shift from year to year.