Unraveling the Relationship Between Magnetic North and Solar East

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    Magnetic Solar
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Discussion Overview

The discussion explores the relationship between magnetic North and the direction of solar East, particularly focusing on how these concepts interact on Earth and potentially on other planets. It covers theoretical aspects, observational phenomena, and variations based on geographic location and time of year.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes the apparent perpendicularity of magnetic North and solar East, suggesting a connection due to the Earth's spinning and its effects on magnetic poles and sunrise.
  • Another participant points out that solar East is not a fixed point on the horizon, varying throughout the year, with specific alignment only occurring on two days annually.
  • A further contribution emphasizes the variability of solar East based on latitude, detailing how the azimuth of the rising sun changes significantly from the equator to the poles.
  • One participant mentions that the magnetic field can flip, which complicates the relationship between magnetic direction and solar orientation.
  • Another participant introduces the case of Jupiter, noting its opposite magnetic poles compared to Earth, while still spinning in the same direction, raising questions about the definitions of magnetic and geographic poles.
  • A participant challenges the initial claim about the Earth's magnetic field generation, stating it is more complex than just the rotation of the Earth’s surface and referencing an external source for clarification.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between magnetic North and solar East, with no consensus reached on the implications of these relationships or the underlying mechanisms involved.

Contextual Notes

Participants highlight various factors that influence the relationship between magnetic North and solar East, including geographic location, time of year, and the nature of Earth's magnetic field, indicating that assumptions and definitions play a significant role in the discussion.

jjustinn
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This morning I was momentarily struck by the coincidence that magnetic North and "solar East" (the direction of the rising sun) happened to be (approximately) perpendicular, but now it doesn't really seem coincidental; as I understand it, spinning of the Earth causes a current that leads to the magnetic poles, as well as the sunrise.

So, if you woke up on an unknown planet with a compass and you faced magnetic north (assuming one existed), would the sun (or whatever astronomical object/objects) always come up over your right shoulder?
 
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The sun does not rise every day at the same point of the horizon. In other words, what you call the 'solar East' lies in the same place only two days in the year.
 
NTW said:
The sun does not rise every day at the same point of the horizon. In other words, what you call the 'solar East' lies in the same place only two days in the year.

I intended to cover that with the weasle-word "approximate", along with e.g. the deviation of magnetic from geological "North", finite propagation speed of electromagnetic effects, general-relativistic corrections, &c.
 
In our planet, what you call 'the solar East' varies widely with the latitude of the observer and the time of the year. On the equator, where that variation is minimal, tha azimuth of the rising sun may depart +/- 22,5 degrees from due East, and that extreme azimuth grows with the latitude of the observer, reaching a maximum of 90 degrees at the arctic circle, where the sun rises due north in the summer solstice, and due south in the winter solstice.
 
Even on earth, It doesn't always work. The magnetic field flips, but the direction of rotation does not.
 
Jupiter's magnetic poles are opposite to Earth's yet it spins in the same direction. In fact, the "north" pole of the Earth is actually a "south" magnetic pole, with the "north" magnetic pole at the southern geographic pole. The reason we call the north pole "north" is because the north pole of a magnet (like the needle in a compass) will seek the magnetic pole located there.
 
jjustinn said:
as I understand it, spinning of the Earth causes a current that leads to the magnetic poles

The Earth's magnetic field is generated by movement of the iron core, and there's a lot more to that than just the rotation of the surface of the earth. Wikipedia is not always reliable, but in this case the article looks pretty reasonable: http://en.wikipedia.org/wiki/Earth's_magnetic_field
 

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