Mariana Trench: from 1872 to today, over a century of discoveries
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The first surveys of the depth of this area of ââthe Pacific Ocean were carried out by the Challenger expedition which between December 1872 and May 1876 made what is considered the first oceanographic expedition, circumnavigating the globe for 68 890 miles.
Measurements made by the Challenger corvette in the area revealed the existence of the depression, detecting a maximum depth of 4 475 fathoms, equivalent to 8 184 m. In 1951 the Royal Navy ship Challenger II explored the area for the first time using sonar, discovering the 10,900m deep depression, later dubbed the Challenger Abyss.
The survey was performed by measuring the return of the signal to the receiver with a stopwatch and, as this was done by hand, it was necessary to apply a correction of about 40 m, so that the depth was corrected to 10 863 m.
In 1957 the Soviet ship Vityaz measured a depth of 11 034 m. However, since subsequent expeditions of the time had not been able to repeat this measure, it was not considered accurate. In 1962 the M.V. Spencer F. Baird recorded the greatest depth of the time, equal to 10 915 m.
In 1984 the highly specialized Japanese ship Takuyo measured a maximum depth of 10 924 m with its multi-directional sonar. On March 24, 1995, eleven years later, the Kaiko, another Japanese probe, obtained a new record measurement of 10 916 m.
In 2009 a measurement was carried out using the Nereus robot, which detected 10 902 m. The last measurement was carried out on 7 December 2011 by mapping the seabed with a scientific sonar placed on a hydrographic vessel; according to the authors of the research, the deepest point is 10 994 ± 40 m below sea level.
The depression owes its name to the oceanographic boat HMS Challenger (1858) which during the expedition in the years 1872-1876 made the first measurements of its depth. It is the deepest point on the earth's surface, located at a depth between 10898 m and 10 994 m below sea level.
It is located in the Pacific Ocean, near the Mariana Islands at the southern end of the Mariana Trench (11 ° 22′N 142 ° 36′E). The closest emerged land is the island of Fais, one of the islands of the state of Yap, located 289 km to the southwest and the island of Guam to 306 km to the northeast.
On June 7, 2020, thanks to the expedition of explorer Victor Vescovo, Kathryn Sullivan, astronaut and first woman at NASA to take a space walk, she too became the first woman to descend to the deepest point of the oceans.