What: Via Wikipedia, Sagan pointed out that "all of human history has happened on that tiny pixel (shown here inside a blue circle), which is our only home" (speech at Cornell University, October 13, 1994.)
Straight as the crow flies. Assuming, of-course, that you are a crow (or any other bird capable of sustained flight), or, that you are able to travel via a flying machine of some sort.
Barbados is an island in the Caribbean. It is not Jamaica. We do not wear grass skirts here (nor in Jamaica as far as I know). The Caribbean is a region of land and sea located on the Planet Earth (third rock from The Sun).
Before you run off (or mouse click away), have you ever thought about how difficult it is locate something? Stop what you are doing and think about it for a second. Or two. If a house guest, or burglar, asks you where your bathroom is, you simply tell him/her (i.e., down the hall, on your left, etcetera). Simple, right? Deceptively so my friend.
In order for you to give those directions, you had to know, a priori, where the hall was to begin with (but it's my house you protest, still...). Put another way, in order for us to locate something (e.g. Item A) in time and space, it seems as though we always have to know the location of an Item B. But in order for us to know the location of Item B, we have to know, once again, the location of Item C.
You see where this is going, don't you? This madness could go on forever. But I won't.