If that mark is related to our appearance because it's the remnants of a spell that pulled us in, could there be more than one? We're appearing in waves at regular intervals. I plan to check for worldwide news reports of any similar phenomena, and if I find them, to look at the timing.

[He doesn't expect to find them all. Not every place is as small, and regularly trafficked, as the Isle of Man; there are plenty of wilderness areas where a strange dead circle that size would never be noticed at all.

Perhaps he should be considering satellite photographs instead.]

If it starts looking like they match up to our appearances, we'd have a schedule and a signal to look for a place where the person casting this spell will actually be.