Here's the thing I like to think about the Transit of Venus across the sun it's all about station point. In other words it's like looking at a still life from a certain spot, things are going to overlap and line up a certain way that they don't from any other spot, all is dependent on your viewing point in relation to the objects in this case the sun and the planet. It could be a ball on a table in front of another ball or a plate.
It's a perfect illustration of something I'm fond of saying in drawing class which is that drawing is about perceiving the visual facts (as opposed to the physical facts) and that the facts are only true from your spot. The second you move they're no longer valid and another set of visual facts takes their place...
I like to think of the distances involved and that if we lived a planet or two over there wouldn't be a transit of Venus across the sun or rather we wouldn't see it not now in this spot at this time. We would have shifted to one side of the still life table and the ball would no longer be in front of the plate.
But it was, briefly, and we got to watch it move and it won't be visible again from this point of view till 2117.
Transit of Venus pictures in the New Yorker