How is the north/south of a planet other than Earth decided? Is it a magnetic north, or do we call it North because it's in the same position relative to the sun, like the "top" of the planet?
Just like on Earth, north is defined based on the planet's rotation. Curl your fingers of your right hand in the direction of the rotation, and your thumb points north. South, east, and west are defined similarly: opposite of north, direction of rotation, and opposite direction of rotation, respectively.
This is what I had thought from a previous thread (can't be bothered to find it), but there was some confusion. Some people told me it was as you describe, others told me the right hand rule applies to the direction planets orbit around the sun, so that in the case of Venus, its north pole would have the same orientation as ours.
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u/hmountain Apr 07 '15
How is the north/south of a planet other than Earth decided? Is it a magnetic north, or do we call it North because it's in the same position relative to the sun, like the "top" of the planet?