Race Against Time: Missing Titanic Submarine Has Less Than 40 Hours of Air Left

Underwater noises have been detected in the area of the search for a sub that went missing while carrying five people to the wreckage of the Titanic, the U.S. Coast Guard says. The submersible had less than 40 hours of breathable air left as of Tuesday evening, and underwater operations have been relocated to try to locate the origin of the noises. The search for the missing sub is an incredibly complex operation, and authorities are working around the clock to effect a rescue.