On Wed, 24 May 2006 20:39:54 +0300, "Ioannis"
wrote:

In other words, let me rephrase the question. Suppose earth's inclination
with respect to the sun was always constant, so that, say, the northern
hemisphere always has summer and the southern always winter. Except for
travelling to the opposite hemispehere, how can we deduce that the axis is
inclined?

If that were true the apparent position of the Earth's pole in the sky
would circle around once a year.