Toph has been shown to be able to sense rock that's disconnected from the ground before, so long as she herself is in contact with any earth anywhere.
Though it's entirely fair to think the Moon is simply Too Far Away. 'cause Toph can't see what's happening in the Fire Nation at all times. So there's clearly a range.
Though it's entirely fair to think the Moon is simply Too Far Away. 'cause Toph can't see what's happening in the Fire Nation at all times. So there's clearly a range.