Mike Rhino ) wrote:
: "Eric Chomko" wrote in message
: ...
: Mike Rhino ) wrote:
: : "Henry Spencer" wrote in message
: : ...
: : In article ,
: : johnhare wrote:
: : It seems to me that a tide-locked body in a dawn dusk polar
: : orbit could well have a permanantly dark side...
: :
: : Mmm, yes, provided the orbit was sun-synchronous -- precesses once
: around
: : the primary per primary orbital period -- which requires a rather
: exact
: : match between the orbit characteristics and the primary's equatorial
: : bulge. I can't see that persisting for very long, however; the exact
: : match is not very stable.
:
: : Suppose that it isn't an exact match so that one day lasts 100 years.
: It
: : would still be an interesting place.
:
: How about a case where one of the poles points in the direction of the
: orbital plane? IOW, at one point in the orbit the north pole points at the
: sun and on the other side of the orbit the south pole points toward the
: sun. Unlike the Earth's or Mars' ~25 deg. axis tilt this other is more on
: the order of a 90 deg. axis tilt.

: Uranus comes pretty close with an axis tilt of 97.86 degrees.

You get the prize! I was fishing for that. Anyway, it is pretty
interesting to think that the poles will be exposed to the sun for part of
the orbit. Like all gas planets it tends to rotate pretty fast, so it
might warmer than expected for the distance to the sun.

Eric

: http://www.solarviews.com/eng/uranus.htm