keplers law

jojo wrote:
Thanks for setting me straight on that!
What is the tilt? 32 degrees?
wow, a little closer or further away and this planet would be intolerable.

23.5 degree tilt - that which you see in standard Earth globes in school or the
library. And we actually do get a little closer and a little farther from the
Sun over the period of one year - closer in January and farthest in July.

That elliptical nature of our orbit and that of Mars is why this recent
opposition was so close. The orbits are not nested ellipses of the same
eccentricity, though they are nearly circular (which is why they are portrayed
that way in textbooks and science programs. We just passed our far point from
the Sun this past July (first week), while Mars was approaching its near point -
thus, we are closer to it than two years ago when the same was not true.


Did I read somewhere that because of the elliptical orbits of Neptune and
Pluto that they
actually change places in their relationship to the sun? meaning, sometimes
Pluto is no the farthest planet?

Yes, so that from 1979 to 1999, Pluto was closer to the Sun than Neptune.