iI recently read a bit about "grand tack" hypothesis. It was extremely intrestinginteresting and it seems to reasonably well explain many features of our solar system. At the same time it supposedly is consistent with our knowledge of other planet systems, which i dontI don't understand. What exactly happened in solar system and at which point , that is so rare out in the other systems? Combination of Jupiter/Saturn showing up at the right places and the right time? IsntIsn't it common that the biggest gas giants appear somewhere over the edge of frost line?