Re: CONCULTURE: dual planets

----- Original Message -----
From: "Andreas Johansson" <andjo@...>
>
> If two roughly Earth-sized planets were orbiting one another closely
> enough to
> have enormous tidal effects on one another, one might expect them to have
> become tidally locked to one another, that's to say, always turning the
> same
> side towards one another. If we additionally assume their mutual orbits to
> be
> close to circular, the mutual tides would be static, that's to say
> unnoticeable. You'd still get tides from the star, of course.
>
>                                             Andreas
Sooo, if my two roughly Earth-sized planets were tidally locked to one
another, thus causing enormous tidal effects, would their mutual orbits have
to be elliptical to cause these tides?  Because you say that if their orbits
are close to circular, the mutual tides would be unnoticeable.  I want the
tidal effects.  (Am I misunderstanding you, as I think I am?)  I also want
them to present the same face to the other, but I could dispense with that
feature.  If they present the same face, each is slowing down the other's
rotation, right?  So their days and nights would be longer?  Ooh.  How could
life survive in that condition?  Would any one planet seem to rise and set
for the other?  In brief, how would an elliptical orbit affect tides,
rotation, etc.?   One planet would be slightly smaller than the other: I'm
imagining a planet earth's size, and another planet bigger than Mars, but
not as big as earth.  Both support life. The bigger planet has larger seas.

Thanks in advance,
Sally

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