Poles on planets

[Andrew*]

Been wondering about this recently.

What exactly are poles and what defines the "north pole" of a planet?

I ask this because Saturn, or Uranus, (can't remember which) has its north pole on the underside in relation to earth's.

Also, do satellites also have poles?

Thanks!

Andrew

[barkis]

Saturns Noth pole is at the bottom of the disc in an astronomical telescope, but only when viewed from the Northern Hemisphere. People down under with see the opposite effect in their scopes. Uranus Axial tilt is 98 degrees, more than a right angle compared with Earths tilt of 23.5 degrees. Each pole of Uranus has a night lasting 21 Earth years, with the opposite pole having 21 years of daylight. When viewed from Earth

Each of Uranus's poles could lie in the centre of it's disc on ocassions. Very strange dynamics compared to the rest of the suns family.

Ron.

[mikkey99]

As far as i understand it the Poles are defined as the axis on which the object spins, So any object that is spinning on one axis has 2 poles,

although how they decide which is north and which is south is beyond me (i think it`s got something to do with the galactic poles)

Mike

[GazOC]

There are 4 poles if you count the magnetic ones.

[Andrew*]

There are 4 poles if you count the magnetic ones.

If there are magnetic ones

[Astroman]

There are 4 poles if you count the magnetic ones.

Good point, Gaz. The poles of a planet, or moon for that matter, are the points about which the planet rotates. The magnetic poles of a planet are defined north and south according to the physics behind magnetism. North and south poles follow the same rules, which I'm embarrased to say I can't really describe. So Barkis' description of Saturn's north pole is magnetic.

The north and south rotational poles are defined by their orientation to their revolution arounf the Sun. All bodies except Neptune rotate counter clockwise when viewed from above the plane of the solar system. Uranus' north pole has drifted toward the Sun for some unknown reason, but it does remain stable with relation to the stars, so Barkis' description of Uranus' 21 year "day" is also accurate.

[Cloudwatcher]

Just came across this thread following the re-shuffle and realised that I could not remember which of the planets do not have magnetic poles! Can someone enlighten me and save me a wade though the asto library?

I do remember though that it is Venus that has a retrograde spin,rather than Neptune, when compared to the other solar system bodies when viewed from 'above'.

CW

[Astroman]

Can someone enlighten me and save me a wade though the asto library?

CW

Mars is the only one I'm aware of, but Mercury may be "neutral" too. Mars used to had one, but pawned it.

[Andrew*]

Can someone enlighten me and save me a wade though the asto library?

CW

Mars is the only one I'm aware of, but Mercury may be "neutral" too. Mars used to had one, but pawned it.

ooh! Who to?

K, I really don't understand this magnetic field business. I thought a planet needed an iron core to have a MF and I thought the gaseous planets were neutral. In fact I thought the earth was relatively unique for having one.

Help?

Andrew

[Astroman]

All you need is differential rotation of different materials at different depths. After all, the Sun has a pretty good field, and it's mostly hydrogen, through and through. Venus, Jupiter, Saturn, Uranus and Neptune also have pretty good fields. Cassini is doing some fantastic work on Saturn's magnetic field. http://hpcc.engin.umich.edu/CASSINI/

Mars pawned it to a some guy named "Eddie", but he can't be reached. He was last seen in Casa Blanca though, so he probably lost it in a card game somewhere.

[Andrew*]

it must have been massive and a fortune to shift about...

oh yeah, and thanks for explaining

[Cloudwatcher]

Mars pawned it to a some guy named "Eddie", but he can't be reached. He was last seen in Casa Blanca though, so he probably lost it in a card game somewhere.

I thought his name was Rick.

Of all the places in all the worlds he would have to turn up in Casablanca! (read with a Boggie drawl.)

CW