In a strange corner of our solar system there are two amorphous alien masses.
They are the size of continents, and it is believed that they spend their time waiting that sustenance falls on them, which they then simply absorb.
Their natural habitat is even more unusual than their diet.
It could be described as “rocky”: all around it there are exotic minerals in unknown shades and shapes.
It is otherwise quite barren, except for of a shining sea in the distance, so huge that it contains as much water as all the oceans on Earth put together.
Every day the “weather” is the same: some warm one.827°C, and its pressure in some areas is equivalent to about 1.3 million times that of the Earth’s surface.
In this crushing environment, atoms deform and even the most familiar materials begin to behave eccentrically: rock is flexible like plastic, while oxygen behaves like a metal.
But this scorching place is not on an alien planet, and those masses they are not strictly wildlife.
It is, in fact, on Earth, just deep inside it.
In that strange world
The environment in question is the lower mantle, the layer of rock that sits just above the planet’s core.
That mostly solid mantle is another world, a place that swirls and is dotted with a kaleidoscope of crystals, from diamonds (of which there are about a quadrillion tons) to minerals so rare that they do not exist on the surface of the planet.
Many of the materials m The most abundant found deep in the earth have rarely been seen on the surface.In fact, the most abundant rocks in this layer, bridgmanite and davemaoite, are largely a mystery to scientists.
They need the ultra-high pressures unique to the interior of the planet to develop and fall apart if brought into our realm.
We can only see them in their natural form when they are trapped inside the diamonds that reach the surface. And even then, it is impossible to know what they really look like inside the Earth, since their physical properties are so different at the pressures under which they normally exist.
For their part, that distant “ocean” does not contain a single drop of liquid.
It is made from water trapped within the mineral olivine, which makes up more than 50% of the upper mantle . At deeper levels, it transforms into indigo-blue ringwoodite crystals.
“At those depths, the chemistry totally changes,” says Vedran Lekić, associate professor of Geology at the University of Maryland ( USA).
“As far as we know, there are some minerals that become more transparent,” he says.
But it is those amorphous masses that most intrigue geologists around the world.
A complicated problem
In 1970, the Soviet Union embarked on one of the most ambitious exploration projects in human history: it tried to drill as deep as possible into the earth’s crust.
That solid layer of rock, sitting on top of Earth’s mostly solid mantle and eventually partially molten core, is the only part of the planet that has never been seen by human eyes.
No one knew what would happen if tried to cross it.
In August 1994, the Kola superdeep well, located in the middle of an inhospitable expanse of arctic tundra in northeastern Russia, had reached staggering depths, extending some .576 meters below ground.
At the start, the team leading the project made predictions about what they expected to find, specifically that the Earth would warm one degree for every 12 meters traveling towards its center.
However, it soon became of course that was not the case: in the mid-1990s 1980, when they reached km, the temperature was already 180°C, almost twice as long as expected.
But then the drill got stuck.
In these extreme conditions, granite ceased to be drillable: it behaved more like plastic than rock.
The experiment was stopped and no one has managed to cross the threshold of the crust to this day.
“We know much less about the Earth’s mantle than about outer space -which we can observe with telescopes-, because everything we know is very, very indirect”, says Bernhard Steinberger, Geodynamics researcher at the University of Oslo (Norway).
So, how do you study an environment that cannot be see or cannot access, where even the chemical properties of the most common materials are distorted beyond all recognition?
It turns out that there is another way.
Inverted Coconut
Seismology involves the study of energy waves produced by sudden ground motion during massive events such as earthquakes.
Among them are the so-called “surface waves”, which are superficial, and the “internal waves”, which travel through the interior of the Earth.
To capture them, scientists use instruments on the opposite side of the world from the earthquakes they are detecting and examine everything that has made its way.
By analyzing the different wave patterns they can begin to reconstruct what could be happening hundreds of kilometers underground.
It is these characteristics that allowed the Danish geophysicist Inge Lehmann to make an important discovery in 1936.
Seven years earlier, a major earthquake in New Zealand had led to a surprising seismic result: a type of internal wave, which can travel through any material, had managed to cross the Earth, but had been “bent” by an obstacle in the way .
And, another type of wave, which cannot pass through liquids, had not been able to pass.
This annulled the longstanding belief that the core was completely solid and led to the modern theory that there is a solid interior enveloped in a liquid outer shell, a sort of inverted bogeyman, so to speak.
A mystery hidden deep within
Screenshot of the video of the LLSVP published in the article of 2016 “Morphology of seismically slow lower mantle structures” by Sanne Cottaar and Vedran Lekić.Over time the method was perfected, making it possible to visualize the hidden depths of the Earth in three dimensions, “using the same techniques as computed tomography” used in medicine, explains Lekić.
Almost immediately, this led to the discovery of the two amorphous masses of the Earth.
Called “large low shear rate provinces” (LLSVPS). in English), are two colossal regions, where seismic waves find resistance and slow down.
One of them, called “Tuzo” is located under Africa; the other, “Jason”, is below the Pacific Ocean.
As with the Earth’s core , these areas are clearly different from the rest of the mantle and are some of the largest structures on the planet.
Their structures are thousands of kilometers wide and occupy 6% of the volume of the entire planet.
Estimates of their heights vary, but Tuzo is believed to have up to 800 km high, which is equivalent to about 90 Everests stacked on top of each other.
Jason could extend 1,827 km up, which translates to about 203 Everests.
Their deformed bodies are clinging to the core of the Earth, like two amoebas to a speck of dust.
“There is 100% certainty that these two regions are, on average, slower than the surrounding region. That is not up for debate”, says Lekić.
“The problem is that our ability to see in that region is blurry”.
Aside of how titanic their forms are, almost everything else about them remains uncertain, including how they were formed, what they are made of, and how they might be affecting our planet.
Scientists know something is going on there and are trying to figure out exactly what, believing that understanding them would help unravel some of geology’s most enduring mysteries , such as how the Earth was formed, the final fate of the “ghost” planet Theia and the inexplicable presence of volcanoes in certain places around the world.
They could even shed light on the ways in which the Earth is likely to change over the next few millennia.
If you want to know about various theories that are being considered about Tuzo and Jason , Click here and read the original note on BBC Travel (in English)
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