Earth reaches furthest point from sun on Friday

We may be only a few weeks removed from the summer solstice, but Earth reaches the furthest point from the sun in its annual orbit on Friday.

The phenomenon is known as aphelion. The opposite, perihelion, when Earth is closest to the sun, occurred Jan 2.

Because orbits have an elliptical shape, Earth's distance from the sun varies, just as the moon's distance from the Earth varies (creating last month's "Supermoon").

It may seem strange that Earth is at its furthest from the sun when it is hottest here in the Northern Hemisphere, but the seasons are linked to the planet's tilt on its axis. The solstice occurred June 21 when the axis was tilted furthest such that the North Pole leans toward the sun.

While Earth's distance from the sun does not influence the timing of the seasons, it does influence their length, according to EarthSky.org. The shape of Earth's orbit makes it such that summer is the longest season of the year in the Northern Hemisphere, while winter is the shortest, with a difference of about 5 days. In the Southern Hemisphere, it's the opposite. (Of course, the official length of the seasons as determined by the solstices and equinoxes are equal.)