SYDNEY, March 21 — Australian Deputy Prime Minister Warren Truss said today the objects spotted on satellite images that sparked an international hunt in the remote southern Indian Ocean for Malaysia Airlines Flight MH370 may have sunk.  The satellite images were taken on March 16. “Something that was floating on the sea that long ago may no longer be floating,” he told reporters in Perth. “It may have slipped to the bottom.” Truss said the search continued in treacherous seas in an area some 2,500km (1,500 miles) southwest of Perth, and Australian, New Zealand and US aircraft would be joined by Chinese and Japanese planes over the weekend. — Reuters