Solstices, Aphelion and Perihelion
Date: 1999 - 2000
How is it that the solstices do not coincide with aphelion and
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).
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.
Click here to return to the Astronomy Archives
Update: June 2012