Thursday, July 05, 2012

On July 5th: Earth Reaches Aphelion

This morning, at about 04:00 UTC (12:00 AM EDT), Earth reached aphelion in its orbit, a distance of 1.017 AU from the sun.

Aphelion/Perihelion Primer

Earth's orbit around the sun is not a circle. Instead, it is an ellipse, though very slight. For this reason, the distance between Earth and the sun varies throughout the year.
At the nearest point in Earth's orbit, Earth is 0.984 AU (91,445,000 miles or 147,166,462 km) from the sun. This point in Earth's orbit is known as perihelion and it occurs around January 3.

Earth is farthest away from the sun around July 4, when it is 1.017 AU (94,555,000 miles or 152,171,522 km) from the sun. This point in Earth's orbit is called aphelion.
The slight ellipse in the earth's orbit does have a slight impact on the amount of solar energy being received by the earth. But it is important to note that this 3.3 percent difference distance does not impact Earth as much as the seasonal variations, which occur because of the tilt of Earth's axis relative to the plane of its orbit.

Scientists utilize the average distance from Earth to the sun as the standard for one astronomical unit (1 AU). This average distance is 92,955,807 miles or 149,597,870.691 km.

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