Name: 死んだ衛星は、南極の下に潜んでいる秘密を解き明かしている (A Dead Satellite Is Unlocking the Secrets Lurking Beneath Antarctica)
Uploaded: 2021-01-14T10:46:23.000Z
Duration: 4 min 48 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

Antarctica contains between 60 and 90 percent of the world's fresh water in the form of

法助動詞 B1

It may look relatively barren, but don't let its seemingly uniform appearance on top

fool you—a dead satellite has now given us clues that something very interesting is

The satellite in question is called the Gravity Field and Steady-State Ocean Circulation Explorer,

pronounced GOCE for short, because the European Space Agency is cosmopolitan

This sleek little sports car of a satellite was created to measure and record fluctuations

in the earth's gravitational field and global mean sea level.

We then use this data to produce a model of the earth called the geoid—hold that thought,

The GOCE satellite completed its mission in 2013, but research teams all over the world

have still been piecing together the data ever since its cute little butt burned up

Because here's the thing about gravitational field data: it tells us what the earth is

like...even the parts of it we can't see.

And here's where the geoid comes back in.

The geoid is a hypothetical ocean—no tides, no waves, no nothin'.

In this model, the only things the world's oceans are influenced by are the earth's

Since objects with more mass have more gravity, the 'water' of the geoid bunches up in

places on earth where there's greater mass, giving us a model of the earth that looks

It's funky shape is our map to all the topographical features on earth!

The geoid lets us better understand ocean currents, sea level rise, and changes in ice

coverage, but it also lets us see inside the earth.

Using three pairs of ultra-sensitive accelerometers, mounted orthogonally to create what's called

a gradiometer, GOCE took measurements that allowed one research team to calculate gravity

gradients, which allow us to see the size and character of all of the earth's topography—including

what's under Antarctica, the least understood of all the continents.

Turns out, it's a patchwork continent, made up of at least three different cratons,

which are remnant rocky cores of long-lost ancient landmasses.

and—get this—each craton has geologic similarities to an existing land mass we know

One is similar to Australia, one matches up to India, and so on.

Now we finally know that this—Antarctica–is the accumulation of what was left over after

supercontinent Gondwana broke up and all the pieces went their separate ways 160 million

This new understanding of the tectonic puzzle pieces locked together at the bottom of the

globe can help us visualize the plate tectonics of earth past.

How did the continental plates move around, what did they bump into, what mountain ranges

and volcanoes and oceans did they create?

But how does knowing what's under Antarctica's icy face add to the science of the present?

Antarctica's ice sheets and glaciers are losing just shy of 300 billion tons of ice

That's compared to the 1980s, when the continent was losing just 44 billion tons a year.

When factoring in melting from other huge ice sheets like Greenland, Antarctica's

melting ice could contribute to up to six feet of sea level rise before the end of the

Plus—we're contending with something called post-glacial rebound.

Turns out, the earth's crust is pretty elastic, and after all that heavy, heavy ice is gone

off Antarctica's back, that landmass, all that bedrock...is going to spring back up.

So it'd be nice to be prepared for how that might play out.

This most recent study, with the help of handy dandy GOCE data, gives us a detailed look

at the rock composition and the configuration of land masses underneath all that ice–the

nature of the rock, the way it's all put together and the way it moves will influence

how fast the ice melts, what directions that water is likely to go in, and how the ice

And remember, these are big freaking ice sheets, so knowing how they may move as they melt

So collecting and analyzing data like this may complete our picture of how earth changed

and molded itself during formative periods of geologic time, helping us understand both

its past and prepare us for its uncertain—but definitely shifting—future.

What else do you think is also lurking beneath our icy continent.

Tell us in the comments below and if you want even more on ancient earth discoveries, check

out my other video on a secret hidden ocean here, don't forget to subscribe, and make

sure you always come back to Seeker to get your geology fix.

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死んだ衛星は、南極の下に潜んでいる秘密を解き明かしている (A Dead Satellite Is Unlocking the Secrets Lurking Beneath Antarctica)

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