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> that included two passes over the Equator (as opposed to shorter ostensible "circumnavigations" circling the North or South Pole) This is a really funny way
by bscphil 7y ago
> that included two passes over the Equator (as opposed to shorter ostensible "circumnavigations" circling the North or South Pole)
This is a really funny way of describing what I assume was a great circle path. It's certainly possible to do a "shorter ostensible circumnavigation" that passes over the equator twice: take an axis through the earth that passes through the equator twice, and take a circular path around that axis of any size. It's only a bias that says such a path counts less than circling the North / South pole.
You can even circle one of the polls and cross the equator twice without it being a real circumnavigation. Fly a path around the Arctic circle, dip down just past the equator, and come straight back...
- dTal 7y agoIt is possible to cross the equator twice without following a great circle, but it's not possible to follow a great circle without crossing the equator twice; perhaps this is the source of the confusion. In other words, you can reasonably say that crossing the equator is a necessary, but not sufficient, criterion for circumnavigation (it is of course not possible to cross the equator only once and return to your starting point). A good additional stipulation might be that the equatorial crossings must be separated by 180 degrees of longitude, plus or minus however tolerant you're willing to be.