3 ms·
I'm curious how Venus's direction is decided, since everything I can find claims it has no magnetic field (except one generated in the atmosphere). Given that:
by Groxx 5y ago
I'm curious how Venus's direction is decided, since everything I can find claims it has no magnetic field (except one generated in the atmosphere).
Given that: how do you define what rotational-pole is "north", to derive east/west? Or is it not based on a planet's qualities, in which case it's likely something solar, and then what would Uranus' "north" (or east) be?
- mcphage 5y agoLooking at it from above, wouldn’t one way be a clockwise rotation, and the other be a counterclockwise rotation?
- retsibsi 5y agoDepends on which 'above' you're looking from though, right? (edit: that wasn't meant to be obnoxiously rhetorical, just to signal that I might be messing up the visualisation myself.) If the planet is rotating around the axis from pole to pole, then from above one pole (or anywhere that side of the equator) the rotation will appear clockwise, from above the other pole it will appear anticlockwise, and from directly above the equator it will just be 'left' or 'right' (or forward or back) depending on your orientation. edit: perhaps from directly above the equator you would still consider the spin to be clockwise or anticlockwise -- but which one would depend on your orientation.
- mcphage 5y agoI would suggest using whatever we consider North for the sun—individually, what way is up doesn't matter, all that matters is we use the same direction for the whole solar sytem.
- SamBam 5y agoThe issue is what is "above." Using the elliptic plane is a fine answer, but is just a convention.
- mcphage 5y agoI guess, for above I'd use whatever we consider "North" for the sun.
- murderfs 5y agoIt's defined relative to the ecliptic plane: the north pole is the pole that's on the same side of the ecliptic plane as Earth's.
- deleted 5y ago[deleted]
- Groxx 5y agoSo it'd be ambiguous / splitting hairs for something arbitrarily near 90 degrees? And given that planets wobble, seems like that'd let poles flip arbitrarily quickly, which would be weird. Uranus might be too far off for this (~8 degrees is a lot more than Earth's wobble, it might take an impact to shift that far and then I think it's fair to reassess), but heck, it got to this point somehow, it'll happen somewhere else too. For relatively perpendicular though, yeah - that largely works I think. But then we should expect most to be "sun rises in the east" as, as far as I'm aware, most solar system bodies orbit and rotate in the same direction as their star does.