The ocean is vast. It covers over two-thirds of the earth’s surface and has an average depth of about 3,720 meters (12,200 feet). But at about 11,034 meters (36,201 feet) deep, the Mariana Trench in the Pacific Ocean’s western part is the deepest ever measured.
But what lies deep beneath the water’s surface? How deep is the ocean? Scientists have several different ways to measure the depth of the sea. The most common way is with a device called sonar. A ship sends out pulses of sound energy and uses how fast the sound travels back to figure out how deep it is.
Another method involves lowering instruments into the ocean for long periods to collect readings every few meters. Here’s all the information you need about how deep the sea is.