Deep Under the Earth's Surface, Discovering Beauty and Science | Francesco Sauro | TED Talks

132,767 views ・ 2015-11-16

TED


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I would like to invite you
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to come along on a visit
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to a dark continent.
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It is the continent hidden
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under the surface of the earth.
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It is largely unexplored,
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poorly understood, and the stuff of legends.
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But it is made also of dramatic landscapes
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like this huge underground chamber,
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and it is rich with surprising biological and mineralogical worlds.
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Thanks to the efforts of intrepid voyagers in the last three centuries --
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actually, we know also thanks to satellite technology, of course --
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we know almost every single square meter of our planet's surface.
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However, we know still very little about what is hidden inside the earth.
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Because a cave landscape, like this deep shaft in Italy, is hidden,
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the potential of cave exploration -- the geographical dimension --
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is poorly understood and unappreciated.
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Because we are creatures living on the surface,
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our perception of the inner side of the planet
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is in some ways skewed,
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as is that of the depth of the oceans
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or of the upper atmosphere.
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However, since systematic cave exploration started about one century ago,
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we know actually that caves exist in every continent of the world.
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A single cave system, like Mammoth Cave, which is in Kentucky,
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can be as long as more than 600 kilometers.
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And an abyss like Krubera Voronya, which is in the Caucasus region,
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actually the deepest cave explored in the world,
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can go as far as more than 2,000 meters below the surface.
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That means a journey of weeks for a cave explorer.
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Caves form in karstic regions.
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So karstic regions are areas of the world
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where the infiltrating water along cracks, fractures,
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can easily dissolve soluble lithologies,
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forming a drainage system of tunnels, conduits --
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a three-dimensional network, actually.
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Karstic regions cover almost 20 percent of the continents' surface,
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and we know actually that speleologists in the last 50 years
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have explored roughly 30,000 kilometers of cave passages around the world,
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which is a big number.
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But geologists have estimated that what is still missing,
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to be discovered and mapped,
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is something around 10 million kilometers.
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That means that for each meter of a cave that we already know,
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that we have explored,
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there are still some tens of kilometers of undiscovered passages.
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That means that this is really an endless continent,
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and we will never be able to explore it completely.
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And this estimation is made without considering other types of caves,
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like, for example, inside glaciers or even volcanic caves,
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which are not karstic, but are formed by lava flows.
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And if we have a look at other planets like, for example, Mars,
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you will see that this characteristic
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is not so specific of our home planet.
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However, I will show to you now that we do not need to go to Mars
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to explore alien worlds.
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I'm a speleologist, that means a cave explorer.
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And I started with this passion when I was really young
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in the mountains not far from my hometown in North Italy,
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in the karstic regions of the Alps and the Dolomites.
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But soon, the quest for exploration brought me to the farthest corner
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of the planet, searching for new potential entrances
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of this undiscovered continent.
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And in 2009, I had the opportunity to visit the tepui table mountains,
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which are in the Orinoco and Amazon basins.
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These massifs enchanted me from the first time I saw them.
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They are surrounded by vertical, vertiginous rock walls
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with silvery waterfalls that are lost in the forest.
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They really inspired in me a sense of wilderness,
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with a soul older than millions and millions of years.
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And this dramatic landscape inspired among other things
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also Conan Doyle's "The Lost World" novel in 1912.
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And they are, really, a lost world.
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Scientists consider those mountains as islands in time,
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being separated from the surrounding lowlands
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since tens of millions of years ago.
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They are surrounded by up to 1,000-meter-high walls,
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resembling a fortress, impregnable by humans.
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And, in fact, only a few of these mountains have been climbed
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and explored on their top.
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These mountains contain also a scientific paradox:
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They are made by quartz,
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which is a very common mineral on the earth's crust,
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and the rock made up by quartz is called quartzite,
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and quartzite is one of the hardest and least soluble minerals on earth.
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So we do not expect at all to find a cave there.
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Despite this, in the last 10 years, speleologists from Italy,
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Slovakia, Czech Republic, and, of course, Venezuela and Brazil,
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have explored several caves in this area.
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So how can it be possible?
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To understand this contradiction, we have to consider the time factor,
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because the history of the tepuis is extremely long,
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starting about 1.6 billion years ago with the formation of the rock,
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and then evolving with the uplift of the region 150 million years ago,
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after the disruption of the Pangaea supercontinent
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and the opening of the Atlantic Ocean.
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So you can imagine that the water had tens or even hundreds of millions of years
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to sculpt the strangest forms on the tepuis' surfaces,
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but also to open the fractures and form stone cities, rock cities,
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fields of towers which are characterized in the famous landscape of the tepuis.
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But nobody could have imagined
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what was happening inside a mountain in so long a time frame.
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And so I was focusing in 2010 on one of those massifs,
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the Auyán-tepui, which is very famous because it hosts Angel Falls,
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which is the highest waterfall in the world --
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about 979 meters of vertical drop.
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And I was searching for hints of the existence of cave systems
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through satellite images,
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and finally we identified an area of collapses of the surface --
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so, big boulders, rock piles --
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and that means that there was a void below.
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It was a clear indication that there was something inside the mountain.
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So we did several attempts to reach this area,
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by land and with a helicopter,
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but it was really difficult because -- you have to imagine
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that these mountains are covered by clouds most of the year, by fog.
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There are strong winds,
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and there are almost 4,000 millimeters of rainfall per year,
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so it's really, really difficult to find good conditions.
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And only in 2013 we finally landed on the spot
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and we started the exploration of the cave.
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The cave is huge.
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It's a huge network under the surface of the tepui plateau,
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and in only ten days of expedition,
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we explored more than 20 kilometers of cave passages.
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And it's a huge network of underground rivers,
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channels, big rooms, extremely deep shafts.
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So it's really an incredible place.
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And we named it Imawarì Yeuta.
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That means, in the Pemón indigenous language, "The House of the Gods."
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You have to imagine that indigenous people have never been there.
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It was impossible for them to reach this area.
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However, there were legends about the existence
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of a cave in the mountain.
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So when we started the exploration,
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we had to explore with a great respect,
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both because of the religious beliefs of the indigenous people,
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but also because it was really a sacred place,
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because no human had entered there before.
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So we had to use special protocols
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to not contaminate the environment with our presence,
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and we tried also to share with the community,
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with the indigenous community, our discoveries.
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And the caves represent, really, a snapshot of the past.
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The time needed for their formation
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could be as long as 50 or even 100 million years,
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which makes them possibly the oldest caves that we can explore on earth.
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What you can find there is really evidence of a lost world.
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When you enter a quartzite cave,
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you have to completely forget what you know about caves --
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classic limestone caves or the touristic caves
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that you can visit in several places in the world.
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Because what seems a simple stalactite here
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is not made by calcium carbonate, but is made by opal,
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and one of those stalactites can require tens of millions of years to be formed.
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But you can find even stranger forms, like these mushrooms of silica
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growing on a boulder.
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And you can imagine our talks when we were exploring the cave.
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We were the first entering and discovering those unknown things,
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things like those monster eggs.
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And we were a bit scared because it was all a discovery,
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and we didn't want to find a dinosaur.
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We didn't find a dinosaur.
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(Laughter)
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Anyway, actually, we know that this kind of formation,
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after several studies,
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we know that these kinds of formations are living organisms.
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They are bacterial colonies using silica to build mineral structures
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resembling stromatolites.
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Stromatolites are some of the oldest forms of life that we can find on earth.
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And here in the tepuis,
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the interesting thing is that these bacteria colonies have evolved
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in complete isolation from the external surface,
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and without being in contact with humans.
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They have never been in contact with humans.
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So the implications for science are enormous,
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because here you could find, for example, microbes
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that could be useful to resolve diseases in medicine,
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or you could find even a new kind of material with unknown properties.
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And, in fact, we discovered in the cave a new mineral structure for science,
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which is rossiantonite, a phosphate-sulfate.
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So whatever you find in the cave, even a small cricket,
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has evolved in the dark in complete isolation.
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And, really, everything that you can feel in the cave are real connections
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between the biological and the mineralogical world.
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So as we explore this dark continent
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and discover its mineralogical and biological diversity and uniqueness,
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we will find probably clues about the origin of life on our planet
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and on the relationship and evolution of life
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in relationship with the mineral world.
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What seems only a dark, empty environment
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could be in reality a chest of wonders
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full of useful information.
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With a team of Italian, Venezuelan and Brazilian speleologists,
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which is called La Venta Teraphosa,
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we will be back soon to Latin America,
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because we want to explore other tepuis in the farthest areas of the Amazon.
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There are still very unknown mountains,
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like Marahuaca, which is almost 3,000 meters high above sea level,
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or Aracà, which is in the upper region of Rio Negro in Brazil.
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And we suppose that we could find there even bigger cave systems,
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and each one with its own undiscovered world.
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Thank you.
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(Applause)
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Bruno Giussani: Thank you, Francesco. Give me that to start so we don't forget.
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Francesco, you said we don't need to go to Mars to find alien life,
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and indeed, last time we spoke, you were in Sardinia
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and you were training European astronauts.
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So what do you, a speleologist, tell and teach to the astronauts?
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Francesco Sauro: Yeah, we are -- it's a program of training
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for not only European, but also NASA, Roskosmos, JAXA astronauts, in a cave.
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So they stay in a cave for about one week in isolation.
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They have to work together in a real, real dangerous environment,
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and it's a real alien environment for them because it's unusual.
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It's always dark. They have to do science. They have a lot of tasks.
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And it's very similar to a journey to Mars
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or the International Space Station.
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BG: In principle. FS: Yes.
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BG: I want to go back to one of the pictures
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that was in your slide show,
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and it's just representative of the other photos --
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Weren't those photos amazing? Yeah?
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Audience: Yeah!
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(Applause)
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FS: I have to thank the photographers from the team La Venta,
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because all of those photos are from the photographers.
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BG: You bring, actually, photographers with you in the expedition.
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They're professionals, they're speleologists and photographers.
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But when I look at these pictures, I wonder: there is zero light down there,
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and yet they look incredibly well-exposed.
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How do you take these pictures?
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How do your colleagues, the photographers, take these pictures?
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FS: Yeah. They are working in a darkroom, basically,
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so you can open the shutter of the camera
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and use the lights to paint the environment.
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BG: So you're basically --
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FS: Yes. You can even keep the shutter open for one minute
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and then paint the environment.
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The final result is what you want to achieve.
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BG: You spray the environment with light and that's what you get.
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Maybe we can try this at home someday, I don't know.
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(Laughter)
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BG: Francesco, grazie. FS: Grazie.
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(Applause)
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