Mariana Trench

Dive into the ocean. We only heard from rumor, saw from pictures and watched from national geographic, but we never went there. On the surface of our 'small' earth, there is a great creature called 'Mariana Trench':

Mariana Trench is the deepest trench in the world or we can simply say that the deepest trench on the earth. The bottom ground distance from our earth surface is about approximately 11 kilometers. Can you imagine how deep it is???

Mariana Trench is located at at the bottom of Pacific Ocean, east and south of Mariana Island which is at east Mindanao, Philippine.

Do you know that the deep of this trench is much deeper than Everest Mountain's height? And because of this trench is so deep, the pressure at the bottom is about thousand times greater that our standard atmosphere pressure (sea surface). Wonder if any animal lives in there. If there is, what kind of animal lives in such high pressure and deep trench. Lets keep wonder about that.

SOURCE:http://combopicto.blogspot.com

My comment: How do we actually measure the depth of this trench? Did the scuba diver dive into the trench with a 'measuring tape'? The answer is a special device known as SONAR is used. SONAR consists of a transmitter and a receiver. The transmitter emit an ultrasonic pulse. This pulse will penetrate through the sea and will be reflected back by the sea bed. it will then received by the receiver. The time taken for the pulse to travel to and fro is measured. The depth of the trench is measured using this formula:
                                     tv= 2d
                                       d = tv/2