Challenger Deep

The Challenger Deep is the deepest known point of the seabed of Earth. It is located in the western Pacific Ocean at the southern end of the Mariana Trench, in the ocean territory of the Federated States of Micronesia. This amazing spot is almost 11 kilometers below the surface of the water.

Scientists have studied this deep place for many years. The area was first found during an expedition by the British Royal Navy survey ships HMS Challenger from 1872 to 1876. Later, in 1950 to 1952, another ship called HMS Challenger II helped scientists learn just how deep it is.

In January 1960, a special vehicle called a bathyscaphe named Trieste made the first trip down to the Challenger Deep. Since then, only a few people have ever made the journey to this incredible place. It remains one of the most exciting challenges in exploration.

Topography

The Challenger Deep is a narrow, slot-shaped area at the bottom of a much larger crescent-shaped oceanic trench. It has three basins. Each basin is about six to ten kilometres long, two kilometres wide, and over 5,930 fathoms deep. The basins line up from west to east, with small mounds between them. The closest land to the Challenger Deep is Fais Island, southwest of it, and Guam, northeast of it. Recent mapping shows slopes and piles of rocks above a bed of soft ocean material.

Surveys and bathymetry

For many years, scientists have looked for and studied the deepest parts of the world's oceans using many different ships. This work still continues today.

The tools used to measure ocean depth can only be so exact, especially in very deep water. This can affect how exact the measurements are. Water conditions, like temperature and pressure, also change how sound travels, which is important for measuring depth.

In 1875, the ship HMS Challenger accidentally passed over the deepest part of the ocean while traveling from the Admiralty Islands to Japan. They used rope to measure depth and found one of the deepest points on Earth, about 26,850 feet below sea level.

In 1951, the ship HMS Challenger II returned to the area and used better tools to measure the depth, finding it to be around 35,400 feet. This is when the name "Challenger Deep" started being used.

Since then, many other ships have visited the Challenger Deep, using better technology to measure its depth more accurately. These include ships like the Vityaz, Stranger, Spencer F. Baird, Thomas Washington, Kana Keoki, Takuyo, Moana Wave, Hakuhō Maru, Yokosuka, Kairei, Melville, Kilo Moana, Sumner, Xiangyanghong 09, Tansuo 01, Sonne, Shiyan 3, Zhang Jian, Tansuo-1, Shinyo Maru, Kexue 3, Kairei, Shen Kuo, and Sally Ride. Each mission has helped us learn more about this deepest part of the ocean.

Study of the depth and location of the Challenger Deep

Since the year 2000, ships with special tools have helped scientists find their place in the ocean very accurately. This has helped them learn more about the deepest part of the ocean, called the Challenger Deep.

In 2014, scientists used old and new information to measure how deep the Challenger Deep is. They used special tools on ships to send sound waves into the water and listen for them to bounce back. This helped them make maps of the ocean floor. More recent studies in 2021 used even better tools and found the depth to be about 10,935 meters, or 35,876 feet, below sea level. Different studies sometimes give slightly different numbers, but they all agree the Challenger Deep is the deepest known point in the ocean.

Direct measurements

Some scientists have gone down directly to measure the depth with special tools. These direct measurements show the depth is around 10,900 to 10,930 meters, depending on exactly where in the Challenger Deep the measurement was taken.

Descents

Crewed descents

1960 – Trieste

Main article: Bathyscaphe Trieste

In 1960, a special vehicle called Trieste reached the bottom of the Challenger Deep. It was piloted by Jacques Piccard and USN Lieutenant Don Walsh. Their journey took almost five hours, and they spent a short time on the ocean floor before returning to the surface.

Trieste dived near 11°18.5′N 142°15.5′E / 11.3083°N 142.2583°E / 11.3083; 142.2583, reaching a depth of about 10,911 metres (35,797 ft).

2012 – Deepsea Challenger

Main article: Deepsea Challenger

In 2012, film director James Cameron made a solo dive to the bottom of the Challenger Deep in the Deepsea Challenger. The descent took about 2 hours and 36 minutes, and he reached a depth of 10,908 metres (35,787 ft). Cameron had to leave early because of a small problem with the vehicle.

2019 – Five Deeps Expedition / DSV Limiting Factor

Main article: DSV Limiting Factor

In 2019, explorer Victor Vescovo used the Limiting Factor to dive to the bottom of the Challenger Deep. The vehicle made several dives to different parts of the trench. The expedition measured depths of about 10,927 metres (35,850 ft) and 10,928 metres (35,853 ft).

2020 – Ring of Fire Expedition / DSV Limiting Factor

Main article: DSV Limiting Factor

In 2020, Victor Vescovo and others made several dives to the Challenger Deep as part of the "Ring of Fire" expedition. They used the Limiting Factor and reached depths of about 10,923 metres (35,837 ft) and 10,915 metres (35,810 ft).

2020 – Fendouzhe

Main article: Striver (bathyscaphe)

In 2020, the Chinese submersible Fendouzhe reached the bottom of the Challenger Deep. It was piloted by three scientists and reached a depth of 10,909 metres (35,791 ft). This made Fendouzhe the fourth manned vehicle to reach the bottom.

2021 – Ring of Fire 2 Expedition / DSV Limiting Factor

Main article: DSV Limiting Factor

In 2021, Victor Vescovo and others continued diving to the Challenger Deep as part of the "Ring of Fire 2" expedition. They made several dives to different parts of the trench using the Limiting Factor.

2022 - Ring of Fire 3 Expedition / DSV Limiting Factor

Main article: DSV Limiting Factor

In 2022, the Limiting Factor returned to the Challenger Deep for more dives. Victor Vescovo was joined by different mission specialists for each dive, exploring various parts of the trench.

Uncrewed descents by ROVs

1996 and 1998 – Kaikō

Main article: Kaikō ROV

The remotely operated vehicle Kaikō made several dives to the Mariana Trench in 1996 and 1998. It reached depths of about 10,898 metres (35,755 ft) and 10,907 metres (35,784 ft). Kaikō was able to collect samples from the ocean floor.

2009 – Nereus

Main article: Nereus (underwater vehicle)

In 2009, the vehicle Nereus made several dives to the Challenger Deep. It reached depths of about 10,902 metres (35,768 ft) and 10,899 metres (35,758 ft). Nereus collected samples from both the eastern and western basins of the trench.

Uncrewed descents near the Challenger Deep

2008 – ABISMO

Main article: ABISMO

In 2008, the Japanese vehicle ABISMO almost reached the bottom of the Challenger Deep but did not quite make it due to a cable issue. It did collect some sediment samples from nearby areas.

2016 – Haidou-1

In 2016, the Chinese submersible Haidou-1 dived to a depth of 10,767 metres (35,325 ft) in the Mariana Trench, making China the third country to deploy a full-ocean-depth vehicle.

2020 – Vityaz-D

In 2020, the Russian submersible Vityaz-D dived to a depth of 10,028 metres (32,900 ft) in the Mariana Trench.

Lifeforms

The first discovery of life in the Challenger Deep happened during the HMS Challenger expedition. They found tiny, single-celled creatures in samples from the deep. In 1960, when people first traveled to the bottom in the Trieste, they thought they saw a flatfish. Many scientists now think it might have been a sea cucumber instead.

More recent explorations found other simple creatures at the bottom, like sea cucumbers, small worms, and tiny shrimp. Researchers have also collected many soft-shelled organisms from the mud. These tiny creatures seem to be specially adapted to live in such deep, high-pressure places. Studies show that tiny microbes can survive even deeper in the ocean floor, showing how flexible life can be.