The ocean is big, deep and impermeable to the laser altimeter that made mapping our less watery neighbor planets possible. To complete a map of Earth's ocean floor, you've got to take to the high seas by boat. The first oceanographic researchers—like those onboard the H.M.S.
Given the high degree of difficulty and cost in exploring our ocean using underwater vehicles, researchers have long relied on technologies such as sonar to generate maps of the seafloor. Currently, less than ten percent of the global ocean is mapped using modern sonar technology.
Over land areas, one can take detailed photographs from airplanes and spacecraft and actually walk around at sites of interest. In the ocean, light only penetrates about 100 m, and it is difficult, with current technology, to take useable sea floor photographs from depths greater than about 10 m (33 ft).
“The intense pressures in the deep ocean make it an extremely difficult environment to explore.” Although you don't notice it, the pressure of the air pushing down on your body at sea level is about 15 pounds per square inch. If you went up into space, above the Earth's atmosphere, the pressure would decrease to zero.
Despite our knowledge of the land we live on and the technology available to us, very little of the ocean floor has actually been mapped in detail. Only 20% of the ocean floor has so far been mapped in detail. The surface of Mars and Venus has been mapped in more detail than areas of the Earth's ocean floor.
More than 80 percent of the ocean has never been mapped, explored, or even seen by humans. A far greater percentage of the surfaces of the moon and the planet Mars has been mapped and studied than of our own ocean floor. Although there is much more to learn, oceanographers have already made some amazing discoveries.
They're also all connected; the world's five oceans are technically one single ocean that covers 71 percent of the planet [source: NOAA]. This makes it difficult to divide, and so ultimately, you own the oceans. You and the rest of the 6.6 billion people swarming over Earth's face right now [source: CIA].
On 23 January 1960, two explorers, US navy lieutenant Don Walsh and Swiss engineer Jacques Piccard, became the first people to dive 11km (seven miles) to the bottom of the Mariana Trench.
While thousands of climbers have successfully scaled Mount Everest, the highest point on Earth, only two people have descended to the planet's deepest point, the Challenger Deep in the Pacific Ocean's Mariana Trench.
Vescovo's trip to the Challenger Deep, at the southern end of the Pacific Ocean's Mariana Trench, back in May, was said to be the deepest manned sea dive ever recorded, at 10,927 meters (35,853 feet).
For the 2022 release of the GEBCO grid, it is estimated that 23.4% of seafloor has been mapped, compared with 20.6% in 2021. The above image shows areas of the global seafloor that are considered mapped within the GEBCO grid.
It's kind of an odd reality that we know more about the surface of the moon and Mars than we do the floors of our oceans.
Marine biologists have a harder time of it, though, because seawater is infuriatingly opaque to radio signals. This makes it impossible either to receive GPS signals or to transmit any data collected back to base.
Most of our world is still shrouded in mystery
Unsurprisingly, we aren't. In fact, 65% of our planet remains unexplored, most of which lies beneath the oceans.
Since its bowels-of-the-earth voyage, only one person has returned to the Challenger Deep: explorer and filmmaker James Cameron in 2012.
Travel to 2,000 meters below the ocean's surface, and the pressure will be approximately 200 atmospheres. That's a lot of pressure! Most organisms with gas-filled spaces (like humans) would be crushed by the pressures that other deep-sea life experience.
At a kilometre under sea level, the pressure is 1,500 pounds per square inch. That's like the weight of a small car pushing on every square inch. Enough to kill you. So you can see how even machines have to be incredibly tough to be able to withstand that pressure without crumpling like an old pop can.
Another reason for the relatively small amount of ocean we have explored is that, at great depths, exploration conditions become extreme. The so-called “sunlight zone” ends at about 200 meters below the surface, making imaging much trickier, and pressure is extremely high.
The Arctic Ocean is the shallowest (mean depth 1361 m) and has significantly larger continental shelves than other oceans. The deep central Arctic Ocean Basin consists of four abyssal plains separated by submarine ridges.
Hidden inside the Earth—within the first several hundred kilometers below the crust—there is another ocean. It is, most likely, the largest ocean in the world. This water is not sloshing around in a big pool.
“Property law states that territorial waters belong to the country and cannot be sold or bought.
Also, the ocean controls our climate by absorbing carbon dioxide, and provides us with pharmaceutical ingredients. Habitats along the coast protect people from storms and flooding.
The law of the sea is a body of customs, treaties, and international agreements by which governments maintain order, productivity, and peaceful relations on the sea. NOAA's nautical charts provide the baseline that marks the inner limit of the territorial sea and the outer limit of internal waters.
Several mountains in Himalayan country Bhutan are believed to be unconquered, namely the world's largest unclimbed mountain: Gangkhar Puensum. Unexplored areas around the world also include small islands, such as Pitcairn Island off of New Zealand, and Palmerston Island in the South Pacific.