Every year in early January, Earth reaches the closest point in its orbit to the Sun, a moment astronomers call perihelion.

Add Yahoo as a preferred source to see more of our stories on Google. The sun shines above the Earth’s horizon. Perihelion, the point when Earth is closest to the Sun, occurs annually in early January ...

Here's how the astronomical phenomenon influences our planet—from the length of our seasons to the way Earth moves through space.