Timewaster's Guide Archive

It would also be possible for a planet to have a highly eliptical path which causes "seasons" due to the proximity of the planet to the star, and with a reasonably small axial tilt, the light could always have a low incidence angle.  In this case, to keep the north and south poles the same (allowing life to exist on the south pole) the axial tilt of the planet could be aligned tangentially to the arc of the planet's path when it is closest to the star.  This would make the two poles of the planet leaning toward the star when they are NOT closest, but also not farthest.

This would create some strange solstices, since the time which the planet spends near the sun is less than that time which it spends away (the velocity of the planet increases as it nears the star . . . see http://en.wikipedia.org/wiki/Elliptical_orbit for more info and read about the vis-viva equation).  This orbit path would cause the planet to spend most of its time facing nearly tangentially to the star, including both the nearest and farthest parts of its path around the star.  So for the north pole, summer could be when the planet is closest and when it is facing the star, fall is as the planet moves farther away, and winter is as the planet is farthest away and as it approaches the star again but is starting to face away.  While for the south pole, summer would be as the planet is approaching the star and facing it and when the planet is closest, fall would be as the planet begins to move farther away is is facing away, and winter is as the planet movest farthest away from the planet and is farthest from it.  Both poles would have the same progression of seasons, and if the axial tilt is enough, they could still have a day/night cycle.  The seasons might not all be of the same length . . .

But I am one of the believers in the "day-night" cycle being actually due to scadrial being so close to the star that it rotated about the star very fast, and the star was just smaller than our sun.  Mercury has an 88 earth-day year, so with a smaller star, it would be possible to be closer and have a fast year cycle.  There are stars with very close gas giants that have been found to have "years" which are a matter of hours or days, so it is certainly possible, and if the star is small enough it could be possible for life to survive provided that its albedo is great enough due to ash-cloud cover.  But that is must my opinion.