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It might be winter here in the northern hemisphere, but the Sun is biggest and closest to us for the entire year today. Earth is at a point in its orbit called perihelion. The Sun is about 91.4 million miles away \\u2013 about one and a half million miles closer than average.

Earth\\u2019s orbit isn\\u2019t a perfect circle. Instead, it\\u2019s an ellipse \\u2013 a shape that looks like a slightly flattened circle. So over the course of a year, the Earth-Sun distance varies by about three percent. The oceans and atmosphere distribute heat around the planet, so the changing distance doesn\\u2019t cause a change in global temperatures.

The date of perihelion isn\\u2019t fixed. Instead, it shifts forward by an average of about one day every 58 years. That\\u2019s because Earth \\u201cwobbles\\u201d on its axis like a gyroscope that\\u2019s running down. About 800 years ago, Earth was closest to the Sun on the winter solstice, in December. And about 4300 years from now, it\\u2019ll be closest on the spring equinox, in March.

The changing distance to the Sun doesn\\u2019t create the seasons. Instead, the seasons are caused by Earth\\u2019s tilt on its axis. But the distance to the Sun does have an impact on the seasons. Earth moves fastest in its orbit when it\\u2019s closest to the Sun, and slowest when it\\u2019s farthest away. That means the seasons are different lengths. In the northern hemisphere, winter is the shortest season \\u2013 about five days shorter than summer, when Earth is farthest from the Sun.
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Script by Damond Benningfield

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