800 kilometers! This is the distance up to which the noise of the blue whale can be heard. Sound can bounce around in different layers of the ocean. It propagates horizontally and crosses the ocean for very long distances. From its scientific name, Balaenoptera musculus, the blue whale can produce a sound of 188 decibels. For comparison, the human voice goes up to 90 decibels and the ear cannot hear above 130 decibels. Photo credit: Humberto Braojos