On the way to Jupiter, an emergency announcement resounded throughout the spacecraft, waking up many students who were sleeping and thinking.

"Urgent notice, route revision. The trip to Jupiter has been cancelled, and all personnel have entered a state of first-level combat readiness! Return to Earth at full speed to participate in the Great Wall of Steel Project! Destination: Mariana Trench! I will send specific tasks to your personal computers. The apocalyptic catastrophe came faster than expected! The first space-time rift to appear was in the depths of the trench, coordinates 11 °20′N, 142°11.5′E. Students, the purpose of our Shuguang Academy is to test our results!"

Mariana Trench (Ma

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ch), also known as the Mariana Trench. It is located at 11 °20'N, 142°11.5'E, that is, the northeast of the Philippines, the Pacific Ocean floor near the Mariana Islands, from Iwo Jima in the north to near Yap Island in the southwest. It has the Aleutian, Kuril Island, Ogasawara and other trenches in the north, and the New Britain and New Hebrides trenches in the south, with a total length of 2,550 kilometers, an arc, and an average width of 70 kilometers. It is estimated that the trench has been formed for 60 million years.

The deepest part of the trench is 6~11 kilometers, which is the deepest known ocean, where high water pressure, complete darkness, low temperature, low oxygen content, and lack of food resources make it one of the harshest areas on earth.

If the world's highest mountain, Mount Everest, is placed at the bottom of the ditch, the summit will not be able to expose the water. Many mountaineers have successfully conquered Mount Everest, but it is extremely difficult to explore the deep sea. In January 1960, scientists successfully dived to the bottom of the Mariana Trench for the first time aboard the deep-sea submersible "Trieste" for the first time. The huge water pressure of up to 1,100 atmospheres at the bottom of the trench is a huge challenge for humans. The deep sea is a high-pressure, dark and icy world, with a temperature of only 2°C (a very small number of seafloors can reach water temperatures of up to 380°C due to geothermal influence).

Amazingly, at such a deep seabed, scientists saw a flounder and a small red shrimp swimming. Some theories suggest that deep-sea trenches are mainly caused by violent depressions in the earth's crust.

Divers have seen well-known shrimp, squid, octopus, gun squid, sperm whales and other large sea mammals in the water at a depth of 1,000 meters, and schools of largemouth anglerfish have been found at depths of 2,000~3,000 meters: new fish species of only 18 centimeters in size have been found in the water column below 8,000 meters. In the deepest part of the Mariana Trench, animals are rarely seen.

In December 2014, scientists discovered a species of fish on the seabed of the Mariana Trench at 8,145 meters, which is nearly 500 meters deeper than the previous record.

The strange creature discovered by the scientists participating in the research program is believed to be a "lionfish" that "when it swims, it looks like a strange cartoon dog with wet wipes floating behind its nose." "This fish is white, with a large head, small eyes, no scales, and is usually slightly longer than a human palm.

University of Aberdeen (Abe

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sity) scientist Jamie Johnson (Ala

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"This deep-dwelling fish is not like anything we've ever seen, and it's not like anything we know," the doctor said. ”

In order to adapt to the deep-sea environment, the physiology of deep-sea fish has changed greatly. These changes are reflected in the muscles and bones of deep-sea fish. As a result of the tremendous water pressure of the deep-sea environment, the bones of fish become very thin and bend, the muscle tissue becomes particularly flexible, and the fibrous tissue becomes surprisingly fine.

What's even more interesting is that the skin tissue of the fish becomes just a very thin membrane, which fills the physiological tissues of the fish with water and maintains the balance of pressure inside and outside the body. That's why deep-sea fish don't get squashed even under such tremendous pressure. In addition, the eyes of deep-sea fish have become very peculiar. Our common goldfish are not only very brightly colored and have particularly large eyes, but also have fun.

Compared with goldfish, fish living in the deep sea have a much richer eye structure than goldfish eyes. The eyes of ordinary fish mostly grow on the sides of the head, while the eyes of fish living in the deep sea grow on the back of the head. Viewed from the front, the two large eye frames of the back fish look like two light bulbs erected. And from above, the two eyes resemble two large circles, occupying the "fortress" part of the head. What's even more interesting is that the fisheye moves up and down, left and right, its eyeball structure is similar to that of a telescope, and it can adjust its focus with ease. The peculiar eye structure is almost a common physiological feature of deep-sea fish.

The deep sea is not calm, and there is a lot of blood and carnage. Scientists have been looking for the 10-meter-long squid that lives on the bottom of the sea. No one has ever seen what it really looks like, but the natural predator of the overlord squid is the sperm whale, and scientists have found a giant squid tooth with a diameter of 20 centimeters in the stomach of the sperm whale. Scientists have concluded that this squid is the overlord squid. However, the natural predator of the overlord squid is actually a sperm whale, which means that they have been bloodshed and killing in the deep sea.

On May 28, 2019, members of the Chinese ocean-going comprehensive scientific research ship "Science" discovered nearly 10 colorful coral forests on the seamount on the south side of the Mariana Trench. It is rare to see a variety of corals and cyplica trees grow together in the forest, just like an "underwater garden".

In January 2011, an international team of scientists discovered that the Mariana Trench contains a large amount of carbon, meaning that the trench's role in regulating the Earth's environment is more important than previously thought. The Mariana Trench acts as a sediment collector, and the amount of carbon converted by bacteria in the trench is higher than that on the 6,000-meter-deep submarine plain.

This suggests that the carbon content in the trench is higher than the researchers previously thought, and they were unaware that there is such a carbon dioxide collection tank in the deep sea. The next step for scientists is to quantify the results of their research, figuring out how much more carbon is in the deep-sea trench than in other oceans, and how much carbon is converted by bacteria, which could help scientists better understand the role of the deep-sea trench in regulating the climate.

In 1957, the Soviet research vessel Vityaz reported a depth of 11,034 m (36,201 ft) and named it the "Mariana Deep Depression", but this data was never measured again and is therefore not used as a standard value.

In 1951, the Royal Navy's Challenger 2 first measured the trench, and Challenger 2 measured the local depth at 11 degrees 19 minutes north latitude and 142 degrees 15 minutes east longitude in an echo positioning mode. In this way, the probe passes through the gradient depth, sends sound waves repeatedly, and then captures the echo with a headset, and the rate of the echo is timed with a handheld computer. It is therefore prudent to subtract the measured depth by one scale (20 fathoms) to arrive at 5,940 fathoms (10,863 m) when formally reporting the new maximum distance.

In 1960, the US Navy submersible USS Trieste set a world record of 10,916 meters in the trench.

In March 2012, the famous Hollywood director James Cameron took the submarine "Deep Sea Challenger" alone and dived nearly 11 kilometers to explore the Mariana Trench in the western Pacific Ocean. At 7:52 local time on the 26th of Guam, that is, at 5:52 Beijing time, Cameron successfully dived to the bottom of the Challenger Abyss, the deepest part of the world's oceans, and returned to the surface on the morning of the 26th local time. This is the second time that humans have explored the Mariana Trench, and Cameron was the first person to dive single-handedly to the "deepest part of the earth".

The National Geographic Society, a partner at the event, said Cameron dived to a depth of 10,929 meters about two hours later to explore the Mariana Trench. The bottom of the trench is eternally dark, the temperature is only a few degrees Celsius, and the water pressure is equivalent to about 1,000 atmospheres. Cameron spent more than three hours exploring the ocean floor, collecting biological and geological samples, taking pictures and videos.

Those who wade in shallow water see fish and shrimp, and those who enter deep water see dragons. Since ancient times, Chinese have dreamed of exploring the mysteries of the deep sea. Now, this dream is coming true step by step through the Jiaolong manned submersible.

Jiaolong is an important high-tech equipment for China's ocean international seabed resources survey and scientific research. Jiaolong is 8.2 meters long, 3.0 meters wide and 3.4 meters high, with an empty weight of no more than 22 tons and a maximum load of 240 kilograms. The maximum speed is 25 knots per hour, cruising is 1 knot, and the current maximum depth is 7062.68 meters.

On June 15, 2012, Jiaolong made its first test dive in the Mariana Trench and finally successfully dived 6,671 meters underwater. Jiaolong conducted a total of six test dives in the Mariana Trench, with a maximum depth of 7062.68 meters, which set a new record for the deepest manned dive of man-made machinery in China.

From June 22 to August 12, 2016, China's "Exploration No. 1" scientific research ship carried out the first comprehensive 10,000-meter abyss scientific research activity in the history of China's marine science and technology development in the Mariana Trench area. China's self-developed "Haidou" unmanned submersible dived 10,767 meters. This time, the "Haidou" not only set a record for the maximum diving depth of China's underwater robots, but also obtained the temperature and salt depth data of the abyss below 10,000 meters and the whole sea depth profile for China for the first time. This is another milestone in China's marine science and technology after the success of the 7,000-meter sea trial of the "Jiaolong", marking the beginning of China's deep-diving scientific research into the era of 10,000 meters. From now on, the 10,000-meter deep sea is no longer a forbidden area for China's marine science and technology community!

In 2017, the Institute of Deep-Sea Science and Engineering of the Chinese Academy of Sciences achieved long-term continuous observation of the 10,000-meter anchor submersible in the Mariana Trench for the first time, and obtained the world's first 10,000-meter seabed artificial seismic profile.

On May 27, 2019, China's ocean-going comprehensive scientific research vessel "Science" officially began to investigate a series of seamounts on the southern side of the Mariana Trench in the western Pacific Ocean, and the "Discovery" remotely operated unmanned submersible on board collected rare deep-water nudibranchs.

In 1984, the Japanese sent the high-energy professional exploration vehicle "Takuyo" into the Mariana Trench, collected data with a multi-narrow beamback locator, and measured a maximum depth of 11,040.41 meters (also recorded as 10,920±10 meters2). In foreign countries, it is generally used to be 10,924 meters deep, such as the CIA and the World Factbook.

In 1992, the Japan Marine Science and Technology Center spent $50 million to develop the "Trench" underwater robot. The Trench is a 3-metre-long, 5.4-tonne cable-controlled underwater robot equipped with sophisticated cameras, sonar and a pair of manipulators to collect samples from the seabed. To develop it is to investigate the Charinger Abyss.

After several failures, on March 24, 1995, the Trench robot was slowly lowered to the bottom of the sea by a 12,000-meter-long primary cable, and 17 monitors in the mother ship's operating room showed images sent back by the submersible. After three and a half hours of "traveling", the Trench reached the bottom of the Charinger Abyss, at which point the bathymetric showed a depth value of 10,903.3 meters, and the corrected depth was 10,911.4 meters. The corrected water depth is the depth corrected by the salt content and water temperature data based on the value measured by water pressure.

"Trench" set a new world record for depth, 15 meters deeper than the previous record. Since then, the "Trench" has also carried out sample collection and photographic expeditions, and people can see from the images it transmitted: on the brown seabed soil, there are some white sea cucumber-like creatures wriggling, and there are several small fish swimming next to it. The deepest point at which fish was previously confirmed was 8,370 meters......

"These are some of the information on this mission. Yun Meng looked at Hua Feng and said calmly.

Hua Feng looked around at Yun Meng and Bai Feng, "Perhaps, we will have a fierce battle this time." Hua Feng carefully reflected on this journey, like a dream that was difficult to wake up from, and now it is time to face the challenge.

At this time, inexplicably he remembered the little fox who helped him through the stage of changing from weak to strong - Nangong Li, I don't know how she is now, whether she occasionally thinks of him.

He knew he couldn't retreat, and so did everyone who was responsible for guarding it. Because behind him are family, friends, compatriots, and all the places in this world where he is still beautiful.

The ship is moving at full speed like a meteor across the sky, but its direction is towards a beautiful dark blue planet in the distance!

"Earth, I'm coming!" Hua Feng said softly.