Den 20. jan. 2011 kl. 05.54 skreiv Roger Mills:
> I'm no astrophysicist, but... I suspect axial tilt is very hard to
> change in any significant way. And planetary orbits, while
> elliptical, are not wildly so. Would such an extreme orbit actually
> be possible? Could it be that in its eccentric orbit, the planet
> comes too close (sometimes) to another large body (a neighboring
> planet, or large moon)?
Extremely eccentric orbits are possible if there aren't any other
significantly large planets nearby. Say if the planet in question
were of the same size as the Earth and had a similar semimajor axis
in its orbit, the nearest major planet would have to be about as far
away as Uranus for an extremely accentric orbit to be reasonably
stable. Otherwise mutual interactions would slowly make the orbit
roughly circular over a few millions of years.