WASHINGTON (Reuters) - Methane bubbles from the sea floor could, in theory, sink ships and may explain the odd disappearances of some vessels, Australian researchers reported on Tuesday. The huge bubbles can erupt from undersea deposits of solid methane, known as gas hydrates. An odorless gas found in swamps and mines, methane becomes solid under the enormous pressures found on deep sea floors. The ice-like methane deposits can break off and become gaseous as they rise, creating bubbles at the surface. David May and Joseph Monaghan of Monash University in Australia said they had demonstrated how a giant bubble from...