Science quiz: Is the Earth's North Magnetic pole a North Magnetic Pole?

a reply to: Bedlam
So the europeans show current direction correctly instead of backwards like the US eh? Thanks, I didn't know that, got my education in the US and never dealt with European circuit diagrams.

originally posted by: Arbitrageur
a reply to: Bedlam
So the europeans show current direction correctly instead of backwards like the US eh? Thanks, I didn't know that, got my education in the US and never dealt with European circuit diagrams.

Brits often don't (nor any of the GB countries). But continental Europeans pride themselves on doing the other way around. We confuse the crap out of each other.

originally posted by: Arbitrageur

1. If you have a compass, the magnetic north needle points north.
2. You learned a long time ago that opposites attract, to the magnetic north of the compass needle is attracted to the magnetic opposite, meaning magnetic south....

Wait... Couldn't the compass be thought of in this way:

1. The magnetic north pole attracts the compass needle's south pole, which causes that needle's south pole point towards North.

2. The guy who made the compass understood this, so he put a "N" on the dial by the compass magnet's south pole, because he knew that it corresponds to north, and he knew what people want that compass to tell them.

I think describing a magnet as having North and South poles needs to change. + and - are better descriptions.

originally posted by: EasyPleaseMe
I think describing a magnet as having North and South poles needs to change. + and - are better descriptions.

Why? Second line

a reply to: Soylent Green Is People
If this was the case, wouldn't all the other magnets not on compasses have the N and S poles reversed from what they are today?

I have no idea what was going through the mind of the people who started the convention, but if I try to imagine the scenario you describe, I end up at a different result than we have today with north and south reversed on all other magnets (besides compass magnets).

The problem is already solved by just sticking to calling the top magnetic pole where the needle is pointing the North pole and sticking to that. You're only reconfusing it, it's not like when you know this the world is suddenly tumbled upsidedown or something. It's just a semantic thing which we already solved. Quit making a problem back out of the solution, will you?

a reply to: Bedlam
I think it makes sense to align electrical and magnetic dipole moments.

RE your previous post can you give an example of a European semiconductor symbol that is shown differently?

a reply to: Arbitrageur

1. If you have a compass, the magnetic north needle points north.
2. You learned a long time ago that opposites attract, to the magnetic north of the compass needle is attracted to the magnetic opposite, meaning magnetic south.

The names “north” and ”south” are arbitrary designations. Bar magnets do not have an N or S on them naturally nor do electric fields have a + or -. The different poles are determined by the way they affect known + electric fields or magnetic north poles, if they attract then they are opposites and if they repel then they are the same. The side of the needle that points towards the North Pole would be the south end of and small magnet. There is a way to figure out the charge of an electric field knowing that opposites attract and I’m sure there is a similar way to do this with polarity of magnetic fields.

Also keep in mind the right hand rule. The pole that spins in a counter-clockwise direction is considered the North Pole as well. Consider Venus which has no intrinsic magnetic field. Using the right hand rule Venus is actually upside down (axial tilt of 177.36°) and thus has a prograde rotation. To claim that Venus spins in a retrograde direction would mean that its tilt is actually 2.64° to the plane of the ecliptic which means that this is another misnomer. Venus actually spins in a prograde direction with an axial tilt of 177.36°, i.e. it's upside down.

originally posted by: EasyPleaseMe
a reply to: Bedlam
I think it makes sense to align electrical and magnetic dipole moments.

RE your previous post can you give an example of a European semiconductor symbol that is shown differently?

As they're different sorts of fields, it would seem to be a bit less confusing to label them differently.

The schematics tend to be different, not the semiconductor symbols. Although they often use IEEE logic symbology that we don't. I'll poke around and see if I can find you some examples that are more wretched than the norm.

a reply to: Arbitrageur

Actually, in the galactic plane, about half the time Earth leads the sun a little and about half the time it lags the sun a little in the galactic orbit.

The Sun’s North Pole is in the direction of galactic rotation since we are @60° tilt to the galactic plane.

60 degrees which is about how much our solar system is tilted with respect to the galaxy.

I guess technically we can say that the Earth is trailing or leading during a solar year in regards to our motion around the galaxy. However considering the right hand rule, which way is North?
[atsimg]http://files.abovetopsecret.com/images/member/c3136968c80e.jpg[/atsimg]
So if we are following the right hand rule then we would say that our solar system is actually tilted by 120° to the galactic plane. I do not know if magnetic North has been measured for the Milky way galaxy yet.

a reply to: Arbitrageur

when we draw arrows to illustrate the direction of current flow, they show the movement of positive charge, but it's nearly always negatively charged electrons that are moving, so because of this, negative charge movement is in the opposite direction of the current flow arrows showing the movement of positive charges (which usually don't move except in things like plasma and even then they don't move as much).

Both charges are thought to be moving in opposing directions. The movement of electrons from one atomic valence to another creates +ions in its wake. Removing outer valence electrons creates a + charge within the atom, adding electrons creates a negatively charged atom. I suppose it’s a philosophical difference to say whether the negative or positive charges are doing the moving since they are action/reaction.

Wow, awesome thread, I never even realized this. Very well done, ATS should have more threads like this! S&F.

originally posted by: Arbitrageur
currently the only thing that is wrong is the naming of the Earth's poles.

Indeed. But then it would confuse geologists: The North Pole is the south.

If we looked at it that way, wouldn't everything else be wrong, including all the textbooks in what they describe as north and south poles of all magnets?

Yeah, it does seem like it. I'm still scratching my head...

To resolve the issue we obviously need to abandon magnetism as the definition for "north" or "south" pole.

a reply to: Bedlam
Different yes but related. I can't think of anything better though.

Do you mean the symbol standards where a transformer is two overlapping circles etc?

originally posted by: Devino
The names “north” and ”south” are arbitrary designations. Bar magnets do not have an N or S on them naturally nor do electric fields have a + or -.

I agree that initially, the designations were arbirary.

However, now that the designations have been made and we have woven those definitions into our science, I would say they are now defined. Thus the definitions we have developed mean that of we want to communicate in terms of those definitions, we can no longer assign N or S and + or - arbitrarily. For example, the right hand rule for positive current flow and the left hand rule for negative current flow give us the magnetic field orientation and isn't arbitrary now that it's defined.

Also keep in mind the right hand rule.

Yes there's some confusion over Venus, but Uranus is tougher being on its side. I'd just put the geographic North pole of Venus in the same general direction as Earth's geographic North pole and I don't feel any compulsion to apply the right hand rule in that case.

a reply to: Devino
I've never seen that diagram before. I'm not really sure about the 60 degrees versus the 120 degres but 60 degrees is the commonly cited figure, though I suspect the sources that cite it may not be paying attention to the right hand rule so it might be 120, which as the diagram shows is another way of expressing 60 degrees except from the other direction. I've never felt compelled to research it further. Is that diagram correct? Do you have a source?

originally posted by: Devino
Both charges are thought to be moving in opposing directions.

In plasma, yes but even in plasma, the positive charges are much more sluggish than the negative charges because they are at least 1900 times more massive, so the negative charges do most of the moving, though not all.

In copper wire, only the negative charges move. In semiconductors we represent electron holes as positively charged quasiparticles but actually it's still the negatively charged electrons that move even in that case.

originally posted by: swanne
Wow, awesome thread, I never even realized this. Very well done, ATS should have more threads like this! S&F.

Thanks. I don't know about awesome but I thought it was interesting enough to share.

To resolve the issue we obviously need to abandon magnetism as the definition for "north" or "south" pole.

This would work for me, see the pink edits to the illustration from the OP:


It would take a little getting used to since like everybody else I was taught the north magnetic and geographic poles were in the same hemisphere, but I think I could adapt to this without much difficulty. All the maps would still be correct based on geographic north.

Then, the next time Earth's poles flip, just revert to the unedited version, the geographic poles stay where they are, and the magnetic poles flip. Works for me.

I'd always just thought of it as "The Magnetic Pole... That is in the North".

Never really gave much though to what polarity it was... does it matter what polarity it is if the handheld compass needle "just works" and points to it?

It doesn't really mean much for electronic navigation, as GPS use the satellites for location, and a "polarity" switch on it would fix things if a flip occurred.

Most people have a rough idea in their heads as to which general direction North is in.

a reply to: Arbitrageur
I must admit that I have taken this for granted as a scientific axiom. If we were to magnetize a compass needle then the side of the needle that points north would be the south end of this magnetized needle. This is after all how magnetism works as you have pointed out. Using this knowledge we deduce that the south pole of a magnet (as in the compass needle) points north. Do you know of any experiment where a bar magnet’s known North Pole points toward the Earth’s North Pole?

…give us the magnetic field orientation and isn't arbitrary now that it's defined.

I was thinking of how a compass needle was painted red or ‘N’ indicating the north pole when this would actually be the compass’ south pole. The ‘N’ is given to the side of the needle that is pointed towards Earth’s North Pole.

I'd just put the geographic North pole of Venus in the same general direction as Earth's geographic North pole and I don't feel any compulsion to apply the right hand rule in that case.

The right hand rule can also apply to rotational directions. I feel that with Venus this is another scientific misnomer. My point is either Venus is upside down (tilted 177.36°) or is in retrograde rotation, not both.

I've never seen that diagram before. I'm not really sure about the 60 degrees versus the 120 degres… Is that diagram correct? Do you have a source?

I made that diagram and posted it here on ATS years ago. I do not remember all of the sources of my research but the program Celestia played a large part.

If you were to download that program you can zoom out and see the directions and orientation of our solar plane of the ecliptic compared with that of the Milky Way galaxy’s. I got the degrees of tilt (60°) from somewhere else and put that diagram together using Microsoft paint. I believe it’s accurate.

the positive charges are much more sluggish than the negative charges because they are at least 1900 times more massive, so the negative charges do most of the moving,

I tend to try and not think of electrons as moving particles as I think this is incorrect, a plasma is of course different. In a copper wire we can remove one of the outer valence electrons from a copper atom (29 electrons) and make this atom positively charged. Removing more electrons makes the + charge higher, adding electrons above 29 gives it a negative charge. No atoms are moving in this scenario. Electrons are attracted to the positive charge so the adjoining copper atoms will lose electrons in the direction of the positive charge (i.e. battery) thus creating +Cu in the process and this starts a chain reaction, elecrtic current flows.

In copper wire, only the negative charges move.

I may be wrong but I think this is another misnomer, perhaps it is an over simplification. Negative charge moves just as much as positive charge. The positively charged body, battery, is where the energy comes from that does work, not the negative. I like to think of the positive potential in a circuit as the compression in a wave and the negative as the rarefaction. They are mutually inclusive.

a reply to: swanne

To resolve the issue we obviously need to abandon magnetism as the definition for "north" or "south" pole.

A true understanding of nature no matter how complicated is far better than a simple misunderstanding. We know how electromagnetism works. There have been countless experiments over the centuries that confirm our understanding in this field. All that is needed is for us to apply this knowledge to the Universe even if it contradicts accepted theories.

a reply to: Devino
Good question about compass versus bar magnets. This video clearly demonstrates that the ~geographic north seeking red tip of the compass needle is a magnetic north pole which seeks the magnetic south pole of the bar magnet (and by inference the south magnetic pole of the Earth which is in the northern hemisphere, which we somewhat erroneously call the "north magnetic pole":

Seeing Magnetic Field Lines


I think you're right that Venus is not without some possible confusion, six of one or half a dozen of the other:

Axial Tilt

Note that there are two standard methods of specifying tilt. The International Astronomical Union (IAU) defines the north pole as that which lies on the north side of the invariable plane of the Solar System;[5] under this system Venus' tilt is 3°, it rotates retrograde, and the right hand rule does not apply. NASA defines the north pole with the right hand rule, as above;[4] under this system, Venus is tilted 177° ("upside down") and rotates direct. The results are equivalent and neither system is more correct.

I happen to prefer the International Astronomical Union perspective, but can't say NASA is wrong, I can only say NASA's view doesn't align as well with my personal preference (or the IAU). Oh well, at least I have the IAU on my side, if not NASA.

About positive charges moving in a copper wire, no statement you make about a battery will make that true. It's the negative charges that move in a copper wire. You can try to apply some kind of quasiparticle theory like we do with electron holes in semiconductors but as I said even in that case where we assume positively charged quasiparticles move, and base our model on that assumption, we nonetheless know it's true that the positive charges don't actually move, only the negative charges. Plasma and ions in solution or batteries are a different story, but neither is a copper wire.

a reply to: Arbitrageur
From your link, Wiki;

Because opposite poles attract, this definition means that the Earth's North Magnetic Pole is actually a magnetic south pole and the Earth's South Magnetic Pole is a magnetic north pole.

Doesn’t this mean that the end of the compass needle that points toward magnetic north is the needle’s south pole? Which end of a compass is north? They are usually painted red/white or red/blue.
Using a bar magnet with labeled north and south poles and a compass we can determine which end of the compass needle is north. If the red end of the compass needle points towards the north pole of our bar magnet then there is your answer. It is the designation of the compass needle that has been inverted for our perspective. I thought this experiment has been done and thus determined that the Earth’s magnetic north pole is in the right location.

add; I just saw your last post. I'll have to look at it when I have more time.