The Earth reached its Perihelion today at 12 UTC, which is 7AM Eastern Standard Time. This is the point in the planet’s orbit where it comes closest to the Sun.

This annual event is due to the elliptical shape of the Earth’s orbit and the off-centered position of the Sun inside that path.  The exact date of the Perihelion differs from year to year, but it’s usually in early January – winter in the northern hemisphere.  The Earth will be furthest from the Sun in July.

While the planet’s distance from the Sun is not responsible for the seasons, it does influence their length.  As a function of gravity, the closer the planet is to the Sun, the faster it moves. Today, the Earth is about 146 million kilometers away from the Sun.  That is approximately 5 million kilometers closer than in early July.  This position allows the planet to speed up by about one-kilometer/second.  As a result, winter in the northern hemisphere is about five days shorter than summer.

The word, perihelion, is Greek for “near sun”.

Image Credit: Academy Artworks