CNN CNN Tonight April 15, 2014 04:10:00
Ocean, he thinks this is what the surface zone nearly three miles down could look like. >> it is dark, it is very cold. >> with pressure so intense it crushes a styrofoam cup to a fraction of its size. the missing plane is believed to be 4500 meters, nearly 15,000 feet down. >> it is flat and the sediment is still. >> the extreme conditions will test the limits of the u.s. navy blue fin 21, beginning the slow painstaking process of mapping the ocean floor. >> people need to have patience. >> reporter: the navy captain says one mission takes 24 hours, two hours down, 16 hours scanning, two hour...