The mystery of a disappearing island in the South Pacific may have been solved by a curious librarian at Auckland Museum.Until this week, Sandy Island was believed to sit between Australia and New Caledonia in the South Pacific, plotted on Google Earth, marine charts and world maps.But when a team of Australian scientists sailed past the island's supposed location on a recent research trip, the island was nowhere to be seen.\We became suspicious when the navigation charts used by the ship showed a depth of 1400 metres in an area where our scientific maps and Google Earth showed the existence of a large island