There's been another potential sighting of wreckage from Flight MH370 - from space.

France has passed on imagery to Malaysia taken from one of its satellites, high above the southern Indian Ocean.

Eight aircraft and a ship spent a fourth day searching the southern Indian Ocean today - but nothing was found. 

239 people were on board the Malaysia Airlines plane when it disappeared 15 days ago. 

Underwater specialist David Mearns says it's crucial to find something soon: