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There is about 5 million kilometres difference in the Sun-to-earth distance between the two extremes of perihelion and aphelion.

The earth's orbit is elliptical, not a perfect circle. We are at perihelion (nearest to the sun) every year on Janary 4th and at aphelion (furthest away from the sun) on July 4th, six months later. These dates can vary by a day or two from year to year.

Obviously on January 4h it is winter in the Northern Hemispehere and summer in the Southern Hemisphere, And on July 4th it is summer in the Northern Hemisphere and winter in the Southern Hemisphere. So it is not the distance that causes the seasons, is it?

Summer and winter are caused by the tilt of the earth's axis and have nothing to do with aphelion and perihelion,

The actual distances involved are

Aphelion 152,097,701 km (1.0167 AU)
Perihelion 147,098,074 km (0.9833 AU)

About a 3% variation. Light takes about 18 seconds longer to reach the earth when it is at aphelion than when it is at perihelion. Light takes 3 seconds longer to get here in February than it does in January, 3 seconds longer to get here in March than it does in February etc. About a tenth of a second extra per day for every day after perihelion,

Source(s):

http://en.wikipedia.org/wiki/earth...

2006-12-21 06:20:57 · answer #1 · answered by Anonymous · 3 0

The Earth's orbit around the sun IS elliptical, but nearly circular, so there is very little difference between Earth's farthest point from the Sun and its closest point. The season's come from the tilt of the earth's axis. The actual distance of the earth from the sun doesn't determine the seasons.

"You can imagine that if the seasons were caused by the Earth's orbit, people in the northern hemisphere and people in the southern hemisphere would have the same seasons. For example, if winter occured because the Earth was far away from the Sun, everyplace on the Earth would be cold at the same time.

But this is not what happens! Summer in the northern hemisphere occurs at the same time as winter in the south, and vice-versa. It turns out that the Earth's orbit is nearly perfectly circular, and the difference between its closest point and its furthest point is very small. In fact, the Earth is furthest away from the Sun in June when it is summer in the northern hemisphere."

2006-12-20 13:08:43 · answer #2 · answered by coco 3 · 0 0

In the Northern Hemisphere, we are actually closer to the sun during winter. The North Pole of the earth is tilted AWAY from the sun, though, so the rays that stike the Earth come in at such an angle as to have more reflect back or absorb into the atmosphere.

2006-12-20 12:56:14 · answer #3 · answered by chocolahoma 7 · 0 0

Further away during the summer

2006-12-20 12:58:36 · answer #4 · answered by oldster 5 · 1 0

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