There is such a thing as the "gravity model of foreign trade", and if you are interested, the following Wiki link will tell you as much as you probably want to know. As far as I am aware, there is no such thing as the "gravity model of FX", though I find it is a useful analogy for thinking about currencies in the Asia-Pacific region. Maybe I can try to popularise it... If you use the analogy of the solar system to think about currencies, then the US dollar is clearly the sun, around which all other currencies revolve. But there are patches of space where other large celestial bodies, further away from the sun can ... (full story)