Which Pole is North?

How is it determined which pole of a rotating celestial body is North?
We all know which of Earth's poles is north but how did this come to be and what about other plants, stars and galaxies? Do we use the magnetic flux or the direction of rotation to determine North?

Magnetic North is determined by observing the alignment of electrons or direction of magnetic flux. What happens if a celestial body does not have a magnetic field, like Venus, or when the magnetic poles shift?
I think we take this for granted and consider it mostly a comparative observation between Earth and other planets but as we continue to explore other worlds this concept needs to be defined.

Magnetic Flux.
Since Venus does not have a magnetic north pole we can not use this to help determine which pole is North. Even if the magnetic north was the determining factor then this would make the Sun's rotation in retrograde because its poles have shifted and north is now where the south pole was.

Right Hand Rule
If the North pole is the observed direction of rotation, clockwise=South pole & counter-clockwise=North pole (right hand rule), then this would make Venus' rotation prograde (i.e. counter-clockwise like the other planets). The thrick is that Venus has an axial tilt of 177.36 degrees, its North pole is upside down but still rotating CCW. To claim that Venus is in retrograde rotation would indicate that the planet's obliquity to its orbit (axial tilt) is only 2.64 degrees rather than the claimed 177.36 degrees.

So I realize that this question brings up some contradictions and ambiguous terms in the concept of a North pole that need to be cleared up. I am interested in other thoughts on this.

reply to post by Devino


This is a very good question, and one astronomers are still debating believe it or not. Ultimately it comes down to how one defines what the north pole is. In the 70's the IAU (International Astronomical Union) basically said, "What ever poles lies north of the elliptic, we'll call north." So in the case of Venus, what would have been dubbed the north pole given the right hand rule you mentioned, would be instead the south pole.

Other astronomers wanted to retain the right hand rule usage. So in the case of Venus, even though its north pole (as determined by the right hand rule) is "upside down", it is still the north pole.

There's been a lot of ink spilled on this issue. Here's one article about it you might enjoy:

Algorithm for IAU north poles and rotation parameters

reply to post by Toromos


Thanks for the reply and I'm glad there is at least a debate over this issue. The idea that we are the center of the Universe is not good astronomy and to say that North is from our point of view sounds too much like 'center of the Universe' thinking to me.

This problem really stands out when we try to compare our solar plane of the ecliptic to the Milky Way's galactic plane.
Which one of the galactic poles is North?
Is our solar system's plane of the ecliptic tilted by 60 degrees or 120 degrees to the galactic plane?
I made a little image to help illustrate this. Notice that at 60* tilt we are upside down in relation to the Milky Way (right hand rule) and at 120* we are aligned upright.

[atsimg]http://files.abovetopsecret.com/images/member/c3136968c80e.jpg[/atsimg]

I think this illustration is correct for the most part however I do not know which of Milky Way's poles is magnetic north.


[edit on 10/4/2009 by Devino]

reply to post by Devino


We are still trying to understand the magnetic field of the milky way, so the question of where's magnetic north isn't easy to answer at this time.

As far as celestial north goes, or true north relative to Earth, it's a matter of convention I think. It's just an easy way to identify the location of something we're looking at it by stating what it's right ascension and declination is. That way we don't have to constantly define what we mean when we're trying to relate a particular location in the skies.

I think the Greeks had some of the first magnetic materials and
wrote about the movement in floating magnetized pins.

Since the north pole star was known for ages and nothing much in
civilization was gong on south of the Equator the standard indication
for north was thus established.

Electrical flow through the Earth does seem to be electron flow entering
the South pole and exiting the north as
files.abovetopsecret.com...


northern lights.
Sounds like the compass people wanted it to point north.

ED: According to the Earth standard, look for electrical activity for
matching polar activity in the emanating light for conducting rocks
like planets. Which are hardly seen by telescopes.
Do stars or galaxys even have electrical poles.


[edit on 10/6/2009 by TeslaandLyne]

Originally posted by TeslaandLyne
Do stars or galaxys even have electrical poles.

Stars certainly do. You can read more about them here:

Stellar Magnetic Field

What makes the galaxy's determination of a magnetic field so difficult is the interior complexity of its motions, and just a basic lack of data.

I assume galaxial north to be true north in relation to the GALAXIES TOP AND BOTTOM.

Originally posted by Devino
reply to post by Toromos

 

Thanks for the reply and I'm glad there is at least a debate over this issue. The idea that we are the center of the Universe is not good astronomy and to say that North is from our point of view sounds too much like 'center of the Universe' thinking to me.

This problem really stands out when we try to compare our solar plane of the ecliptic to the Milky Way's galactic plane.
Which one of the galactic poles is North?
Is our solar system's plane of the ecliptic tilted by 60 degrees or 120 degrees to the galactic plane?
I made a little image to help illustrate this. Notice that at 60* tilt we are upside down in relation to the Milky Way (right hand rule) and at 120* we are aligned upright.

[atsimg]http://files.abovetopsecret.com/images/member/c3136968c80e.jpg[/atsimg]

I think this illustration is correct for the most part however I do not know which of Milky Way's poles is magnetic north.


[edit on 10/4/2009 by Devino]

North ansd South is a definition.

Earth magnetic pole is determined by which way the magnetic current travels. To day the magnetic current moves from the center of our core and out from our magnetic South pole and back in at the magnetic North pole.

We use this magnetic current to create a compass. Because the magnetic elements within iron always line up with the magnetic current produced by the Earth core. When molten Iron cools down the magnetic iron always line up to the main current produced by the Core. So we can use a Iron needle to see which way the current moves.

True North and True South is determined by the angle compared to earth center point and the rotation/spin. Which gives us the equator "Middle". 90* from equator is true N and true S. But still its on a tilt compare to the Sun.

We cant use earth magnetic current to navigate in space. Because the compass would be affected by other bodies that produce a magnetic current.

Thanks for the reply's.
I will have to review some ideas about some theories of the Earth
magnetic field and the presence of magma that might not indicate
the core of the Earth is not solid.
So Earth with a solid metal core and magma coming from another
process, how is the magnetic field produced.
Earth being a conductor, allows currents from the Sun to pass
through it.
So thats a new theory.
All from electrical charges from the Sun.
This might work for galaxy's and sounds like this theory is from
the Electric Universe theories.

I think it is logical to assume that all galaxies have magnetic fields that surround all of its stars. I also think that this field effects each star and in turn each star's magnetic field effects its planets and so on. This is simple action/reaction between electricity, motion and magnetic fields which does sound like proof for an electric Universe.

I am also interested in the origin for the designation of the north pole. The idea of measuring the flow of electrons seems quite simple but, when was this first done? The research I have done on the origin of our geographic co-ordinance system and our measure of time seem to have been in vain, possibly predates recorded history. I did learn that ancient civilizations knew a lot more than was originally thought.

If the Universe has an electrical potential that directly effect matter causing it to spin thus generating a magnetic field, then this gets real interesting. Notice in my illustration how our solar plane of the ecliptic is edge on to the center of the Milky Way. This is also a view from Earth's winter solstice BTW.
Do we stay fixed in this position as the galaxy rotates thus changing how we face the galactic center (galactic equinoxes and solstices) or do we always face edge on towards the center?
If there is a change with our relative position then this would have a changing effect on our local magnetic fields and energy.

[atsimg]http://files.abovetopsecret.com/images/member/c3136968c80e.jpg[/atsimg]

My goal has been to understand our relative position and how we move with all of the stars and the galaxy. I think what we desperately need here is an animated virtual perspective of all the motions that is accurate.

And you do know that because of axis of the earth rotates and changes direction in a circle (the astronomical term is 'precesses'), our North Star changes every couple thousand of years or so right?

Matter of fact, Polaris will cease becoming the North Star in about 40 more years when our North Star will become Thuban. The last time we experienced a change in our North Star was about 2500 years ago when it was Vega.

The Northern Pole rotates through the following Stars:

Thuban (Alpha Draconis)
Alpha Cephei
Vega
Polaris

reply to post by fraterormus


I am aware of this but precession of the equinox is irrelevant to Earth's plane of the ecliptic. The orbital plane for Earth and all the other planets in our solar system remain the same overall. The orbits of the planets are titled (orbit inclination) and eccentric, I am also aware that the respective orbit nodes and perihelions change as well. None of these motions, however, effect our edge on tilt of 60 degrees to the Milky Way.

There are other motions underway that could effect this alignment, like our galactic rotation or stellar oscillations but I don't know if it changes. My guess is that it does change as we rotate around the galactic center and this edge on alignment happens twice for every galactic orbit, once on each side.

Earth's axis is tilted to the ecliptic (orbital path around the Sun) by around 23.5 degrees. Precession is the slow circular motion of the Earth's axis that advances our alignment by around 1 degree every 72 years. Every tropical year for Earth (equinox to equinox) comes about 50.3 arc seconds early due to the slow circular motion of the axis. A sidereal year is actually a little bit longer than what we consider an Earth year, Earth has more than one length for a year.

Tropical (equinox to equinox)----------------365.2421897 days
Sidereal (fixed star to fixed star)------------365.256365741 days
Anomalistic (perihelion to perihelion)--------365.259641204 days
Eclipse (Moon's node to Moon's node)-------346.620046296 days
Gaussian (Kepler's law for a = 1)------------365.2569 days
Julian (based on Julian calendar)-------------364.25 days
Gregorian (based on Gregorian calendar)---365.2425 days

[edit on 10/9/2009 by Devino]

reply to post by fraterormus


The earth's axial precession is about 26,000 years. Thuban will not be the North Star in 40 years. If that were the case we would already see it being the North Star. Polaris will make its closest approach to Celestial North in about 2100 CE.