Challenger Deep Facts

The Challenger Deep is the deepest known point of the seabed.

The Challenger Deep is a depression in the ocean named after the British Royal Navy survey ship HMS Challenger, whose expedition of 1872 – 1876 made the first recordings of its depth. Since then, twenty-two people have descended to the bottom of the depression.

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Challenger Deep Facts for Kids

  • Challenger Deep is the deepest part of the world’s oceans.
  • It lies at the southern end of the Mariana Trench in the Western Pacific Ocean.
  • It’s approximately 10,935 meters (35,876 feet) deep
  • There have only been 9 manned descents into this slot. 
  • US Navy submersible Trieste made the first descent in 1960.
  • Jacques Piccard and Lieutenant Don Walsh manned it. The two spent 20 minutes at the bottom.
  • Sound pulses were sent through the ocean to measure it.
  • Temperatures range from 1°C to 4°C.
  • Mariana Trench was formed by colliding massive slabs of oceanic crust in a subduction zone.
  • Sirena Deep is the second deepest point in the ocean east of Challenger Deep.
  • This area has microbes that feed on hydrogen and methane.
  • The mud at Challenger Deep is home to more than 200 different microorganisms.
  • Tectonic plates on the ocean floor created the Mariana Trench

What is the deepest part of the ocean?

The Mariana Trench is the deepest part of the ocean. It is located in the western Pacific Ocean and extends for about 1,500 miles. The trench is about 35,876 feet deep–that’s more than seven miles below sea level!

The water pressure at Challenger Deep (the deepest point in the Mariana Trench) is 1,000 times greater than sea level pressure. In other words, if you were to stand at sea level and dive down to Challenger Deep, the water would be pressing down on you with the force of 1,000 elephants!

Despite these intense pressures, life can exist at depths of 11,000 meters. Scientists have found fish and other organisms living near the bottom of Challenger Deep. These creatures have evolved special adaptations that allow them to survive in this harsh environment.

Even though we know life exists at these great depths, we still don’t know a lot about it. In fact, scientists only explored Challenger Deep for the first time 60 years ago!

Since then, they’ve made some amazing discoveries about what lives there. For example, did you know that fish are able to see light even when they’re deep underwater?

What ocean is home to the Challenger Deep?

The Challenger Deep is located in the Mariana Trench, which is the deepest point in the ocean.

The Mariana Trench lies beneath the Western Pacific Ocean

The depths of other oceans have not yet been explored because they are not as deep as the Mariana Trench. However, there are four other trenches that exceed 10 kilometers in-depth in the Western Pacific Ocean.

The Challenger Deep is home to amphipods with high levels of contamination similar to that found in Suruga Bay off Japan. These creatures serve as an important indicator of environmental health because they live near the bottom of the food chain and are sensitive to contaminants.

The Challenger Deep is also home to a wide range of pollutants, which raises concerns about the long-term effects of this type of pollution on the ecosystem as a whole.

What was the first vessel to reach the Challenger Deep?

On January 23, 1960, Jacques Piccard and Don Walsh descended into the Mariana Trench, the deepest part of the ocean.

The vessel was called the Bathyscaphe Trieste

It had a spherical observation room. A gasoline tank was attached to this observation chamber. The buoyancy of gasoline makes it a good choice for deep-sea diving due to its resistance to compression.

It took nearly 5 hours to descend into Challenger Deep. 

As Walsh and Piccard reached the seafloor, they observed their surroundings. 

In the ship’s light, they could see a dark brown ooze, shrimp, and some fish resembling flounder and sole.

During the descent, the Plexiglas viewing window cracked, so the men only spent about twenty minutes on the seafloor. 

They then unloaded the ballasts (nine tons of iron pellets and tanks filled with water) and surfaced. 

The ascent took only 3 hours and 15 minutes.

How deep is the Challenger Deep?

The Challenger Deep is approximately 10,935 meters (35,876 feet) deep.

The temperature at the bottom of the trench is between 34 and 39 degrees Fahrenheit and the pressure at the bottom of the trench is 15,750 PSI.

Who was the first person to reach the Challenger Deep?

Jacques Piccard

Humans have only descended into the Challenger Deep once, more than 60 years ago. In 1960, Jacques Piccard and Navy Lt. Don Walsh reached this goal in a US Navy submersible, and a bathyscaphe called the Bathyscaphe Trieste

The expedition to Challenger Deep was fraught with danger. The Trieste had to withstand huge pressure from the water above it, and there were concerns that it might not be able to make the journey back up again.

On the way down, the Plexiglas viewing window cracked. However, On January 23, 1960, they reached the bottom after 5 hours of descent.

Their achievement was celebrated all over the world, and they even received a telegram from President Eisenhower congratulating them on their success!

What is the pressure like at the Challenger Deep?

The pressure at Challenger Deep is quite intense! In fact, it’s 1 atmosphere per 10 meters of depth. This means that at the deepest point in the ocean, the pressure is over 10,000 pounds per square inch!

It’s no wonder why scientists rarely mention this area when talking about deep-sea exploration. In literature-the, the conditions are quite extreme.

Interestingly, the bottom water temperature is between 1°C and 4°C. So even though the pressure is so high, it’s still quite chilly down there!

What is the temperature like at the Challenger Deep?

It’s hot and cold. No sunlight can reach the Mariana Trench, so you might expect it to be cold. However,  the water there is usually between 34 and 39 degrees Fahrenheit.

What kind of life is found at the Challenger Deep?

Xenophyophores, amphipods, and small sea cucumbers (holothurians) are the most common organisms at the bottom of the Mariana Trench.

Xenophyophores are single-celled, single-celled organisms that eat by surrounding and absorbing food

What are some of the challenges of exploring the Challenger Deep?

Exploration is inherently dangerous, as I’m sure you know already. It takes a lot of planning and preparation to get to the bottom.


Implosion is the inward collapse, the opposite of explosion. If the design of your sphere is incorrect, you’ll be in trouble. Suddenly, with barely a warning, the sphere could buckle.

Penetrator Failure

You have a dead short somewhere, and one of the pins in your electrical penetrator melts, causing the device to fail. At 16,000 psi, the water jet erodes the inside of the penetrator, letting seawater blast in.


It’s a race between your life support running out and freezing to death if you get stuck on the bottom. Because the water outside is just above 0°C, it won’t take long for your body heat to run out.


All the gadgets in the sub can catch fire, and with O2 pumping into the pilot sphere, fires can spread fast. The sphere has a fire extinguisher, but it may not be enough for a large fire.

Viewport Failure

You see cracks in the viewport. Cracks spread quickly throughout the thick volume of acrylic, and it begins to collapse. Boom! It sounds like a supersonic piston, and the cork pops.

What have we learned from exploring the Challenger Deep?

Since 1873, when the HMS Challenger first successfully explored the deep sea, humans have been fascinated by what lies beneath our oceans. Each subsequent expedition has taught us more about these dark depths and the strange life that exists there.

The greatest depth at which life has been found is 8 km in the Puerto Rico Trench, discovered in 1948 by a Swedish expedition. However, it’s important to note that this is not an absolute limit; it’s possible that deeper creatures exist somewhere out there waiting to be discovered.

In 1956, Jacques Cousteau took some of the first photographs down to the deepest part of the ocean – the Romanche Trough. These images revealed a world unlike anything we had ever seen before; a place where eternal darkness reigns and temperatures barely rise above freezing point.

Since then, researchers from Woods Hole Oceanographic Institute have conducted several robotic dives to even greater depths, reaching as far as 35,767ft in 2009.

The Haidou and Nereus submarines are two such vehicles that have allowed us to explore previously uncharted territory.