Humankind loves to look up towards new challenges
and greater aspirations. Whether we’re building immense skyscrapers,
climbing the tallest mountains, or reaching for the stars—we never stop striving to
better ourselves. But our world has plenty more to explore and
discover even if it means reaching a little lower. Perhaps a lot lower. Deep beneath the sea, buried far underground,
and even at the very center of the Earth. Let’s take a look at seven of the deepest
places in the world. Far beneath the chill waters of the western
Pacific Ocean, the Marianas Trench stretches across the seafloor in a realm that light
has never touched. The deepest point—appropriately called “Challenger
Deep”—has been measured at 10,994 kilometres below sea level, give or take forty meters. The bottom of the trench was seen for the
first time on January 23rd, 1960 by oceanographer Jacques Piccard along with US Navy Lieutenant
Don Walsh from within a cramped bathyscaphe. They missed the Challenger Deep by a few meters
but they were still able to observe the floor of the Marianas Trench, which was noted to
be “light and clear, a waste of snuff-colored ooze.” Despite the crushing weight of the water above,
the intrepid explorers were certainly shocked to find life waiting for them at the bottom,
in the form of “some type of flatfish, resembling a sole, about one foot long and six inches
across.” If sixteen thousand pounds of pressure per
square inch can’t dissuade life from finding a way, perhaps there’s a lesson to be learned
there. Later expeditions revealed other extreme forms
of life, like giant amoebas measuring ten centimeters in diameter. Before the nightmares set in, it might be
worth noting that the amoebas didn’t exactly resemble the single-celled organisms as we
think of them, but more like a sea sponge or coral. Scientists dubbed these creatures “xenophyophores”,
which is science-speak for “they look like aliens.” The era of discovery continues even to this
day; Hollywood director and science buff James Cameron performed the deepest solo sub dive
into the Marianas Trench on March 25th, 2012. Using his custom built submersible, he collected
samples of the oozy sediment and even captured 3D video of the entire dive—hoping to gain
a better understanding of the ocean’s depths and spur support for future expeditions. There’s certainly a lot left for us to discover
down there. As long as we don’t anger Cthulhu, we should
be okay. Just a short distance southwest of Johannesburg
in South Africa lies perhaps the greatest achievement in the world of mining since the
invention of the pickaxe. Miners in the Mponeng Gold Mine have been
hard at work since 1981, sifting the earth to produce gold from a vein that averages
less than a meter wide. An interesting dichotomy, when you consider
that the Mponeng Gold Mine is the deepest mine in the world—and it’s all thanks
to that relatively tiny golden thread. Most of the work is done between 2.4 and 3.9
kilometers deep, the latter number being the current world record for mining depth—and
the digging continues, extracting 5,400 metric tons of rock daily. Expansion efforts seek to ensure the mine’s
long term viability. Purely a precautionary measure, as in 2012
alone the mine produced around 11,500 kilogrammes of gold. That’s $460 million of the golden good stuff. If you’re still undecided on a career path,
perhaps you might consider becoming a miner. But it’s not all fun and games that far
down in the Earth’s crust. The closer you get to the core of our planet,
the hotter things get in turn. This is an effect known as the “geothermal
gradient”, and it’s a constant concern for the intrepid miners of the Mponeng Gold
Mine. If you were to descend to the deepest point
in the mine, the temperature of the surrounding strata would reach temperatures of up to sixty
degrees Celsius. Consider the harsh, unyielding stone surrounding
you—and you’ve got the makings of an oven. Inhospitable working conditions, for sure. Thanks to a constant stream of slurry ice
pumped through the mine, the temperature is maintained at a far more bearable thirty degrees
Celsius. Still a sweltering day in the mines, but hey—at
least you won’t end up broiled. Caves have long held a special sort of allure
for explorers. Natural fissures in the terrain which offer
nooks and crannies for those brave enough to test their shadowy depths. Krubera Cave—located in a particularly porous
area of Western Russia known as the Arabika Massif—isn’t just any old cave. It bares the unique distinction of being the
deepest cave in the world. It is with no small measure of respect that
some cavers have taken to calling it the “Everest of the caves”—evoking images of the danger
and excitement that many find in summiting the tallest mountains. Krubera Cave was recognized for its record
depth in August of 2004, after a particularly stoic band of cave explorers followed its
twisting path downward to a total depth of 2,080 metres. It’s the only natural formation known to
humankind greater than two kilometers deep, and it even has a reserve of water at the
very bottom known as the “terminal sump”. That’s as far as the team of cavers could
go with the equipment they had with them. In 2007, and again in 2012, a Ukranian diver
by the name of Gennady Samokhin climbed down to the sump with all the necessary equipment
to plunge into the icy water and map the tail end of the cave. He earned world records with both dives, and
added another ninety-eight meters to the depth total in the process. So if you’ve ever fancied a long climb with
a brief swim at the bottom, there’s a bloody scary idea for you to add to your next vacation. Once you’re through spelunking in Krubera
Cave, head east into Siberia to find the next stop on our whirlwind tour of the world’s
deepest places: Lake Baikal. The depth isn’t the only interesting thing
about this crescent shaped reservoir cutting through the Russian mainland—though it is
both the deepest freshwater lake and the deepest continental body of water to be found on our
planet. Besides reaching incredible depths, there’s
plenty of other facts about the lake to get excited about, especially if you’re a scientist. Geologically, Lake Baikal is the oldest freshwater
lake in the world, and contains nearly 20% of the world’s unfrozen freshwater reserve. Not to say that it doesn’t freeze over from
time to time—it is Siberia, after all. The lake and its surrounds are also home to
an incredibly diverse collection of flora and fauna, with some estimates identifying
around one 1,340 different species of animals living harmoniously with upwards of 570 species
of plants. A lush, thriving ecosystem to be catalogued
in and around an ancient lake of remarkable depths—and those eager scientists might
even be able to make it home for dinner. Provided that they live somewhere nearby,
of course. We’re going to have to bend the rules a
bit for this next one. Though the Bentley Subglacial Trench in Western
Antarctica isn’t technically covered in water, it is—well, covered in water. But not the wet kind. The trench is actually the lowest point on
the Earth not covered by an ocean or other form of flowing water, sitting at 2.5 kilometers
below sea level. As you might expect, “subglacial” means
that it is sequestered beneath the frozen mass of a majestic glacier. Surrounded by many other similar stretches
of ice all across the Antarctic continent. This means that the Bentley Subglacial Trench
is actually subterranean, though it’s still a point on the Earth’s surface. Just not one you could walk to. I told you we’d have to cheat a bit. It was named by the Advisory Committee on
Antarctic Names in 1961, in honor of Charles R. Bentley and his contributions to Antarctic
research as the chief traverse seismologist of Bryd Station, between 1957 and 1959. Seeing as he was the one who led the expedition
which first located the trench and recorded its depth, it seems an appropriate legacy
for him to leave behind in the snowy wastes. Who knows—there could be a secluded spot
in Antarctica just waiting for you to slap your name on it as well. When in doubt, start drilling straight down
and don’t stop until the Earth itself rejects you. Not exactly sensible advice, but someone involved
with the Kola Superdeep Borehole project must have heard it somewhere and really took it
to heart. During the Cold War, there was a constant
back-and-forth between the United States and the Soviet Union, each seeking to one-up each
other on the global stage. Scientific endeavors flew fast and furious,
one of the results being the Soviets’ decision to set a drill into the ground of the Kola
Peninsula and dig as deep as possible. There were certainly valid scientific reasons
for the project, but it almost sounds as if they were just waiting for an excuse to do
so. The drilling began in 1970 and didn’t stop
until 1994, producing what we call today the Kola Superdeep Borehole, the deepest hole
ever drilled to date and the deepest artificial point in the world, reaching a mind-boggling
twelve kilometers into the crust of our planet. That’s deeper than even the Challenger Deep. In the end, the borehole encountered the same
issue as the miners in the Mponeng Gold Mine—things get really hot that deep underground. Temperatures at the end of the shaft climbed
to around 180 degrees Celsius—no, not Fahrenheit, but Celsius. That’s a brain-melting 356 Fahrenheit. The equipment simply couldn’t continue to
function in those conditions, and so the Kola Superdeep Borehole had reached its end. But rumors continue to swirl about what exactly
brought about the conclusion of the drilling. There are campfire ghost stories about microphones
lowered into the shaft, which recorded the sounds of tortured screams. What’s really going on at the center of
the Earth? Well let me tell you… At the very center of our planet lies a sphere
of solid iron—at least, as best we can tell with current data. Deeper than the molten mantle and liquid metal
outer core, the inner core seems to be formed of a massive, non-uniform ball of iron. It is this core, and the extreme heat as a
result of several factors working in tandem, that serves to heat the planet from within. The same heat which wards off any attempts
to burrow through the crust; it’s as if the underworld is feverously trying keep us
at bay. There must be something going on down there. The estimated temperature at the boundary
between the molten metal of the outer core and the solid inner core is around 5,600 degrees
Kelvin. To put that in some perspective, the temperature
of our Sun’s surface is 5,800 degrees Kelvin—only two hundred more, some predict that the Earth’s
core might even be hotter than the surface of the sun. Thanks to pressure, friction, and radioactive
elements, the Earth essentially has a miniature sun burning at its very heart. Perhaps we will never get to see the very
core of the Earth with our own eyes, but we can dream. And every crevice, borehole, or trench we
discover can bring us that much closer to understanding the unsearchable depths beneath
us. And no matter how deep we go, it can only
get warmer and brighter once the darkest places are behind us.
