drag: function(ev, ui) {
          var universe = $('#universe');
          var offset = universe.offset();
  
          var dragTop = ui.position.top +
                        universe.data("top0") - dragDelta.top;
          var dragLeft = ui.position.left +
                         universe.data("left0") - dragDelta.left;
  
          $('#universe')
            .css('top', dragTop).css('bottom', -dragTop)
            .css('left', dragLeft).css('right', -dragLeft);
        },
        refreshPositions: false
      });
    });