the brink of alien and terrestrial, lies two vast structures with unknown origins, and

scientists call them...

Earth blobs?

Uhh wait what?

Did I read that correctly?

Yes, yes I did read that correctly.

These 'blobs' have been a big geologic mystery that researchers believe are having

an untold effect on our planet and it's baffled scientists for over 40 years.

So what do we know about them?

Well, Earth blobs have picked up this rather un-sciency name because they look sort of

blobby with round, soft edges.

No, not that type of blob.

Scientists call them Large Low Shear Velocity Provinces, because waves of energy slow down

through these zones, but boy, that's a mouthful so let's just stick to Earth blobs for now.

They're hidden underneath Earth's crust, like really, really deep - about 2,000 kilometers

deep.

These blobs are so massive that if we moved them to Earth's surface, the International

Space Station would need to navigate around them.

So to better understand these gigantic structures, we need to journey into the center of the

earth.

They begin where Earth's mantle meets the outer molten core.

In the 1970's, scientists discovered that one of the blobs sits under the Pacific ocean,

while the other one sits under Africa and part of the Atlantic ocean.

So we know their general location and we know that these regions are different from the

surrounding mantle material because seismic waves move through these massive regions slower

than their surroundings.

But there are still many unanswered questions.

No one knows for sure where they came from, how long they've been around, or even what

their role is on the planet.

But yah know, scientists love a good mystery hidden deep within the Earth's crust.

So it's been an ongoing debate ever since they were discovered 40 years ago with a whole

range of ideas trying to explain them.

One hypothesis has described them as plumes of hot upwelling rock that connect to surface

volcanoes to form island chains like Hawaii and Iceland.

Another has speculated that the blobs are disrupting Earth's magnetic field.

And others have suggested that the blobs are connected to super volcanoes that at one time

caused extinction events.

So yeah... the ideas run from the generally benign to the apocalyptic.

But these are just hypotheses.

Because it's impossible to reach these depths in one piece—temperature and pressure would

kill you —scientists have to rely on a multitude of techniques to tell us what the interior

looks like, and maybe even explain how these mysterious regions affect our planet.

One way is with seismic tomography, a technique that helps us look below the crust by tracking

and calculating seismic waves.

This was how scientists actually discovered the blobs in the first place.

But while the method revealed where the blobs are and how large they are, it can't really

tell us much about their density.

So one researcher turned to a new technique called tidal tomography to peer under Earth's

crust.

It uses sensitive GPS measurements to track Earth's body tides and can give us a better

gauge of the blobs' density.

Preliminary results showed that the blobs were pretty dense and could be composed of

iron and have similarities to primordial material.

While geochemists are analyzing the chemical composition of lava samples to help determine

what role blobs could play on volcanoes.

One study, looking at underwater lava flows along Costa Rica, suggested that at least

one of the blobs may have been a source for an extinction level event millions of years

ago.

So evidently more research is needed to demystify the blobs before we make any conclusions.

What's important to keep in mind is that each of the earlier ideas may present a different

picture of Earth's inner workings and the role the blobs could play on our planet, which

is why these regions are so scientifically interesting.

They could tell us very different things about the planet, from its earliest beginnings to

the magnetic field to even super volcanoes.

But until Brendan Fraser figures out a way to journey back to the center of the Earth,

we'll use the techniques at our disposal to reveal the mysterious blobs wrapped around

the heart of our planet.

Come on Brendan, we're counting on you.

If you liked this episode, let us know if there are any other mysterious science phenomenons you'd like us to

cover down in the comments. Make sure to subscribe and thanks for watching.