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Name: Vicki
Status: other
Age: 40s  
Location: N/A
Country: N/A
Date: 1999 - 2000


Question:
How is it that the solstices do not coincide with aphelion and perihelion?

I understand that the seasons are due to tilt of Earth's axis, and my question is not meant to imply anything about distance from the sun as a cause. It seems like the positions at which maximum tilt occurs should be in phase with the two "extreme" points of Earth's orbit. I guess that the answer has something to with (a) the orbit is not being a true ellipse but an ellipsoid and/or (b) the directional orientation of the axis, e.g., it points not only toward Polaris but also east of the perihelion position (assuming a side view with perihelion to the observer's right).


Replies:
The Earth's tilt is not related at all to its orbit. It is constant. The seasons result from this constant tilt causing the north pole to be more sunward during one half of the orbit, and the south pole more sunward during the other.

Tim Mooney



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