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

  • ice.

  • 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

  • hiding underneath.

  • 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

  • like that.

  • 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 geoidhold that thought,

  • we'll come back to that in a second.

  • 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

  • in the earth's atmosphere.

  • 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 oceanno tides, no waves, no nothin'.

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

  • gravity, and the rotation of the earth.

  • 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

  • a little bit like a misshapen ball

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

  • So GOCE's mission was really important.

  • 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 topographyincluding

  • 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.

  • andget thiseach craton has geologic similarities to an existing land mass we know

  • and love today.

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

  • Now we finally know that thisAntarcticais the accumulation of what was left over after

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

  • years ago!

  • 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?

  • Well, the ice is melting.

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

  • per year.

  • 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

  • century.

  • Pluswe'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.

  • Yeah.

  • 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 icethe

  • 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

  • may shift as it melts and breaks apart.

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

  • is pretty important.

  • 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 uncertainbut definitely shiftingfuture.

  • 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.

  • Thanks for watching!

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

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