How Deep Is The Sea?

To know the depth of the ocean, you need to know some amazing numbers.

About 71 percent of the earth’s surface is covered with water. All these waters together occupy a total of 332,519,000 cubic miles or more than 1,386,000,000 cubic kilometers of earth.

Even if the amount of water in the ocean were put into each one-gallon milk container, a total of 352,670,000,000,000,000,000 containers would be needed.

Since we cannot have so many milk containers, let’s understand this with a different example. In theory, you could cover the entire United States (including Alaska and Hawaii) with seawater up to a height of 82 miles (ie 132 km).

Most of the common questions people have about the ocean are about the depth of the ocean. How deep is the ocean? Where is the deepest part of it? And what is the average depth of the ocean?

This article provides answers to these questions about the depth of the ocean.

Average Depth Of The Ocean

Strictly speaking, there is only one ocean on Earth. So it’s a bit confusing when all 5 major regions of this vast body of water are called “oceans” separately: ie, the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Arctic or Northern Ocean, and the Southern Ocean.

These are collectively known as the “World Oceans”. Usually when people talk about “oceans” they mean the world’s oceans. The example given earlier in relation to the amount of sea water, ocean is also meant as the world ocean.

Of course, ocean depths are not the same everywhere. The depth of the sea varies according to the geographical location. The distance between the seabed and the water surface at any point on the map can be affected by various canyons, underwater ridges, or other features.

Using sonar, radar and satellite technology, scientists have determined the average depth of the world’s oceans. About 12,785 feet (3,897 meters). Equal to about 2.4 miles or 3.8 kilometers.

Deepest Place In The Ocean

The deepest of the 5 oceans into which the world’s oceans are divided is:

Molloy Hole is the deepest place in Arctic or North Ocean. It is located at a depth of 18,599 feet (5,669 m) below sea level.

Which is the deepest place in the Indian Ocean? Probably an unnamed area of ​​the Java Trench, which lies 23,917 feet (7,290 m) below sea level.

The South Sandwich Trench is the deepest part of the Southern Ocean that surrounds the continent of Antarctica. Its depth is 24,229 feet (7,385 m).

The deepest point in the Atlantic Ocean is the Milwaukee Deep in the Puerto Rico Trench. which is 27,585 feet (8,408 m) deep.

The Mariana Islands, located in the Pacific Ocean, have a deep undersea trench extending to the east. Adventure seekers and science fiction writers have never lost interest in this place.

Its name is Mariana Trench. And it is the deepest point not only in the Pacific Ocean, but in the entire world ocean. This spot is marked on our map as “Challenger Deep”. Its location is on the western side of the Pacific Ocean.

Measuring the exact depth of the Challenger Deep is quite difficult. But according to a 2019 study, it lies about 35,843 feet (10,925 meters) below sea level.

How deep is this depth actually? Very very deep. In fact, the depth of this point in the Pacific Ocean is greater than the height of Mount Everest. The summit of the Himalayas is only 29,025 feet (8,848 m) above sea level. The movement and interaction of the Earth’s tectonic plates has created these deepest troughs, so have the world’s highest mountains.

How Do We Measure Ocean Depth?

If you’ve seen Joe’s, The Meg, or any other deep-sea thriller, you’ve seen some of the scariest sea creatures imaginable.

Not all of these creatures are fictional, some of them actually existed. Like Megalodon—a shark the size of a school bus! We don’t know how deep in the ocean they lived. However, with modern technology we can say that today’s shark sightings are usually found down to about 2,000 meters (6,500 ft) deep. But how do we know this information?

We will now look at the methods by which scientists and researchers accurately measure the depth of the ocean.

Just like mountains and dunes on Earth’s surface, the ocean floor or sea surface is not completely flat. Just as there are plains at sea level, there are all kinds of landforms, including canyons, trenches, and underwater volcanoes.

The science of measuring the depth of the Earth’s oceans, lakes and rivers is called bathymetry or bathymetry. Bathymetric maps and ordinary land maps are almost identical. Both highlight the topography of a particular area. Scientists and researchers can measure the depth of the ocean in different ways.

Let’s take a look at these methods now:

  1. of gold The most common and fastest method of measuring ocean depth is using sounding. Using technology called sonar, ships can learn the shape, features and topography of the ocean floor. and based on this creates ocean maps. The English word Sonar is an abbreviation of ‘sound navigation and ranging’.  This device sends sound waves to the bottom of the ocean and measures how long it takes for the echo to return. “Echo” here refers to sound waves reflected from the ocean floor and returned to the sonar device. Multibeam echosounders (MBEs) are a type of sonar device. It sends fast sound waves in fan-like formations to scan the ocean floor. The US National Oceanic and Atmospheric Administration (NOAA) uses this MBE device to measure ocean depths. Some ships send sonar devices back and forth to map specific areas of the ocean floor.
  1. Radar and Satellite Radar can also measure the depth of the sea. Although it is not as fast as Sonar. Like sonar, radar also sends out a type of wave. The difference is that the waves transmitted from the radar are essentially radio waves. It is a type of electromagnetic wave. But electromagnetic waves travel slower from air to underwater and their energy is weakened as they pass through water. Radar is mainly better for atmospheric measurements. However, another method by adding radar and satellites is used to measure the depth of the sea. A radar altimeter is an instrument that can measure the distance from the ground to the air based on how long it takes for radio waves to return from the surface to the satellite. The surface of the sea is invisible to our eyes, the radar altimeter sends radio waves there, these waves bounce off the sea surface and return to the satellite. Depending on how much time it takes, the depth of the ocean can be determined. 

Researchers can also map different regions of the ocean using data from radar altimeters. This method has even been used in spacecraft studying the surface of Venus.

We have technology like sonar to measure ocean depths. Even then, it takes a long time to map a section of the ocean floor. It would take about 125 years to map the entire ocean floor, so only a tiny fraction of the world’s oceans have been mapped. But since the surface of the ocean mimics the topography of the ocean floor, we already know what the ocean floor looks like.

But this does not diminish the importance of measuring the depth of the sea. And the appeal of this information is in no way diminished. Because of these technologies, scientists have been able to discover various deep sea creatures like the Ninja Lanortanshark. 

Scientists have also benefited greatly from these data for navigation at sea, making maps for navigation, and furthering environmental conservation research.

Due to the advancement of technology we now have all the modern methods of measuring the depth of the ocean. As a result, we are getting to know marine ecosystems better. Expanding our knowledge of the ocean and our impact on it.

How The Depth Of The Sea Was Measured In Earlier Days

Before the use of sounding and radar to measure ocean depth, ship captains and their crews used a different method to measure ocean depth. Earlier sailors used a device called a lead line. In this method the lead was hung on a rope, the rope being marked every 6 feet, this length being called a fathom. Sometimes a piece of cloth or leather was also tied to the rope. One would then drop the rope into the water, and when the lead bead reached the bottom of the water, sailors would use the marks on the rope to measure and record the distance to the bottom of the ocean.

This lead line was the most valuable method for measuring depth in navigation. It has been in use since the fifth century BC. Through this, sailors could understand how deep the water was at a particular place and whether their ship would get stuck in this water. 

The inside of the bottom of the lead line was open and filled with grease. As a result, it would retrieve samples from the ocean floor. Lead lines help the captain determine whether the ocean floor contains sand, rocks, or mud.

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