‘We don’t know what they are’: Underwater noises provide glimmer of hope in submersible search

A Canadian military surveillance aircraft has detected underwater noises during its hunt for the missing Titanic tourist submersible, providing a glimmer of hope for the public about the five people on board. Mike Armstrong explains how this discovery is impacting the operation, the vast size of the search area, and how much oxygen is believed to be left in the sub.

• Titanic sub’s oxygen is dwindling. How can passengers prolong survival?