About orbits

[The Warthog]

It occurred to me to wonder if the major axes of the planetary orbits are more or less aligned, or are they all over the place? It would seem to me that if the planets coalesced out of a disk that was orbiting the sun, the shape of the orbits would reflect the original orbit of the disk. Then again, I'm a psychology major, not a physics major...

[Kaptain Klevtsov]

I think they're all more or less lined up so that they appear on the ecliptic.

Kaptain Klevtsov

[lunator]

WH

Yep they are all very close to each other so you have them on th eplan of the solar system, although the jostling in the past has meant that the planets polar axes and orbital planes are not perpendicular to each other. We are fortunate to have the Moon as a stablising influence.

Ian

[The Warthog]

Yeah, OK. I know about the ecliptic and the orbital plane. What I am wondering is, each planet's orbit is an ellipse, with a major and a minor axis. I am wondering if the major axes of the planetary orbital ellipses are lined up, when the orbits are seen from above the solar system?

[Kaptain Klevtsov]

Are they real elipses, or do they rotate their major axis over time in a spirograph kind of manner? ISTR that this precession is normal and that would mess up the alignment from the word go.

I'm probably wrong on this, either way I'm hoping to learn what really happens.

Kaptain Klevtsov

[The Warthog]

Are they real elipses, or do they rotate their major axis over time in a spirograph kind of manner? ISTR that this precession is normal and that would mess up the alignment from the word go.

I'm probably wrong on this, either way I'm hoping to learn what really happens.

Kaptain Klevtsov

You may be right, but that's why I asked the question.

[Astroman]

The minor axes of the planets do indeed precess as CC suggests. The major axis of all the planets is of course the Sun, and it wobbles a tiny bit, as do all planets around stars, (which is the method we've discovered the most so far).

BTW, I'm back! 8)