Were the "North" and "South" poles' names picked randomly or based on some science?

Question

When I view Earth from a distance in my mind, I always think of the North pole as being "up", and South pole as being "down". Yes, I know Earth is tilted, but it's still up/down.

This means my "camera" is always placed in a certain way in this endless void. But it's based on nothing other than my perception that there is a "North" or "up" on Earth.

But why are they referred to as the North/South poles? Did they just pick these at random? Could the South pole just as well have been the North pole to humans?

I don't think it really matters, but it's something which I've often thought about and cannot find the answer to.

Answer 1

The Earth is more or less spherical, and more or less rotates steadily about an axis between the north and south poles, with a very long term (26000 years) precession and shorter term nutations. That the Earth is more or less spherical and that it rotates about an axis was known to the ancients.

This daily rotation makes the Sun rise more or less in the east, set more or less in the west, and at noon in places north of the tropics, the Sun is south of the zenith (vertical). Northward is where it gets colder the further north one goes. In addition, the northern hemisphere is blessed in having Polaris as a guide star by which one can determine which way is north.

This north-south, east-west set of directions were very important to seagoing civilizations. Regarding maps, which direction was at the top of a map and which direction was to the right varied from civilization to civilization. Some had south at the top and north at the bottom. Others had east at the top and the west at the bottom. Yet others had north at the top and south at the bottom. It wasn't until Mercator's time (mid to late 16th century) that European mapmakers settled on arbitrarily placing north that the top of a map and east to the right. That was about the same time that western European hegemony started, which is why modern maps almost universally have north at the top. It's a bit arbitrary, a bit chance that north is at the top of most maps.

Regarding etymology, this is the wrong site for that kind of question.

Answer 2

Since you didn't specify which kind of poles you're talking about: there is a specific reason that North and South magnetic poles are named as such, unrelated to why we consider North to be "up" by convention geographically.

"North" is the direction a North-seeking compass points to, and "South" the direction a south-seeking compass points to.

A bar magnet has two poles: a magnetic north (where magnetic field lines point outwards) and a magnetic south pole (where magnetic field lines point inward). A magnetic north pole is attracted to a magnetic south pole, and vice versa. So a compass needle, which is a magnetised metal needle, will point towards a magnetic pole of the opposite sense to that of the magnetised tip of the needle.

The Earth's magnetic field has a magnetic south pole located in the Northern hemisphere, and a magnetic north pole located in the Southern hemisphere. So a compass magnetised with a north magnetic pole at the needle tip will "seek" the Earth's magnetic pole in northern hemisphere, and vice versa.

The physics of magnetism was not understood historically in order to decide the naming convention for the geographical directions, rather the sense of magnetic poles were named to match the geographic sense later on when the physics was understood.