ฝึกพูดภาษาอังกฤษด้วยเทคนิค Shadowing จากวิดีโอ: The Ocean Is Deeper Than You Think. We Need Better Maps.

The ocean is terrifying...

....but the maps that we have of our oceans are actually terrible. If you look at Google Maps you might think that we know the precise topography of all of this. But that's a lie.

We know less about the ocean floor than we do about the surface of Mars... by a lot. How is that possible? We have mapped Mars to a resolution of 5 meters per pixel. For comparison, we've mapped the land on Earth to about 30 centimeters. But most of our oceans? 1.5 kilometers. Meaning 300 times less detail. And that's a big problem because we're using the ocean all the time. We're laying cables across it to carry your internet traffic, we fight wars in it, we get food from it, we use it for global trade. 71% of the earth's surface is water! And yet, we have a surprisingly limited view of what's below it. But hang on, we're smart. Why is that? Well, cartographically speaking, water sucks.

For Mars or Earth's surface, we can take pictures. But light doesn't get to the ocean floor so we need other ways to see it. And the good news is that we're developing that tech right now.

There is a terrifying, incredible, alien world right there are on our own planet. And finally, we're using technology to see it more clearly. In this video, we're going deep - with some help from a friend - to show you how we're mapping the ocean, the surprising things that we've found in the depths, and why this new technology could be huge if true.

"Map the ocean floor -" "map the ocean floor" "map an ocean floor that nobody has ever mapped before..." "piece together a complete map of all the world's seabed..." "Oh my god this one's freaking gorgeous..." "Nobody really knows quite what's down there..." Mapping the ocean is shockingly hard, largely because they're just so much deeper than most people think. Imagine that you walk off the coast into the water. At 10 meters or 33 feet deep you're already experiencing an entire additional atmosphere of pressure on your body. At 214 meters, you're passing the verified record for a human diver with no equipment and it's quickly getting darker and colder. At 828 meters, you're the depth of the tallest building on earth, the Burj Khalifa. And a thousand meters down the world is unrecognizable. No light from the surface can penetrate these depths. No light! The whole rest of the way is blackness and you're less than 10% of the way down. 1220 meters, you're in the territory of the deepest military submarines . 3800 meters, you hit the Titanic. Just above it is where we think the infamous OceanGate submersible imploded. The pressure down here, over 350 atmospheres, collapsed the faulty submersible in a thousandth of a second. For reference, in space it would take you up to 90 seconds to die. So, I mean, if you ever have to choose between a few seconds in space or in the deep ocean... choose space! Except... if you want to see aliens... choose the ocean.

Dory: "It's... so... pretty...." Anglerfish: Dory and Marlin: AHHHHH!!!!!

I just... I love the ocean. The deepest recorded natural point is 10935 meters or 6.8 miles deep.

You might have heard of this spot: Challenger Deep. If you put Mount Everest into the water upside down, there would still be over a mile until you get to the bottom. It's roughly the average cruising altitude of a 737 airplane. The ocean is incredibly deep and scary and amazing which as you can imagine makes it very hard to map. So we have over 70% percent of our Earth most of which light can penetrate and humans can't go... it's the last unknown place on earth.

When I look at Google Maps, I can see what looks like a topography of the entire ocean. But if we "haven't mapped the ocean in detail"... what am I actually looking at?

STEVE: "We don't have good maps of the global seabed." "What quite a lot of those maps have been derived from is used in satellite gravity data." That's Steve Hall, marine scientist and ocean mapping expert. He told me that because light can't penetrate past a certain distance, satellites use a method that totally blows my mind and has changed how I'm going to look at the ocean forever. Okay, here goes: The surface of the ocean isn't flat.

It is ever so slightly the shape of what's below it.

Yeah. STEVE: "The gravitational field of the earth isn't absolutely constant, so if there's a deep trench, there'll be ever such a slight dip down in the sea surface above it. If there's a mountain, there'll be ever such a tiny bulge." To create some of the topography that you see on Google Maps we're using satellites to send radar pulses down to the surface of the Earth measure the height of the water in different places and then estimate the shape of the ocean floor. The next time that you look out across the water, just just take a second to appreciate how absolutely bananas this is! But this radar on the ocean surface technique doesn't give us a very precise view of the seabed. We still need to fill in a lot of detail...

STEVE: "You're looking at a pretty good approximation of what the shape of the sea floor is like and a lot of that has been put together by good quality but educated guesswork." For example, see these bumps and ridges right here? We know that those are underwater mountains, but if you try and zoom in it gets blurry. There's just not enough data to make a clear image. Luckily, we have other methods, created a device that could send acoustic waves into the water and record the time that it took for them to bounce back. You've heard of this. This is sonar. But it wasn't until the 1940s that a woman named Marie Tharp turned those sonar measurements into maps. Those maps showed mountains and valleys and all kinds of things that we'd never seen before. They were some of if not THE first ocean floor maps ever created, but they've largely been forgotten by history...

However, in researching this story, I discovered that rare physical copies of them exist at the Library of Congress in Washington DC.

Now, I'm in New York but I have a friend in DC... and he loves maps...

JOHNNY: "Maps" "on every map" "earth map?" "this map" "map it out" "maps" "map" JOHNNY: "I collect a lot of maps..." I asked my friend and fellow video journalist Johnny Harris to go find these old ocean maps so we could really see the progress that we've made.

"Hey!" "Hey" "Listen I have a favor to ask. Do you want to go to the Library of Congress and look at some cool maps?" JOHNNY: "Absolutely, are you kidding? I will gladly take any excuse to go to the Library of Congress and stare at beautiful original maps." Oh they're just like pure art. Oh my god, this one's freaking gorgeous.

Okay come here, I want to show you. You can imagine them out there on the ocean, pinging sound off the bottom of the ocean floor, and they just come back with this raw data that's basically like a bunch of lines with numbers on them. Like it's super raw, just telling them how deep each of these sections were. It's not a map though. Not yet. And you can see Marie Tharp just drawing with like a colored pencil to connect all of these lines to start to get an idea of the contours of the bottom of the ocean. So then she took that data and she connected the dots and created these like 2D slices of land that are called profiles. And this is where you start to see it actually looks like mountains now. So then after the profiles her and her research partner Bruce Heezen in took these 2D profiles and then they started to sketch by hand what parts of the ocean might look like.

I mean this must have taken years. And then you do that with enough regions of the ocean and finally you put them all together other and you start to get like a real map. At first it was still pretty crude, like here's some of these early versions of what the ocean map looked like. This is one of the first, if not the first published map of the ocean floor from 1957. This is one of the most beautiful maps I've ever seen. This one from 1977 is considered a work of art. I mean look at it...

As beautiful as all this is, a lot of this was like filling in the blanks. And that's a problem if you're trying to get a like hyper realistic map of the ocean. So they needed a better way...

CLEO: I just love these. Marie Tharp's maps were so beautiful! But like Johnny showed, there were big parts that they had to essentially make up. Marie Tharp was using data from those narrow lines of sonar from old shipping routes. Today, we still use sonar to map the ocean floor, but instead of sending a few beams down, sonar devices send thousands in a fan that can span several kilometers. This is a really big deal because it makes it possible to map much larger areas at a time. Tou remember this blurry part of the map? Researchers just gathered sonar data for that part of the ocean, and now we can see it in much much more detail. But we still haven't done that for most of the ocean! And we need to step it up!

In part to better navigate the deep ocean to do things like lay internet cables, but also to save lives by better predicting tsunamis and storms and sea level rise, or to use the ocean for new kinds of renewable energy, or because in a crisis you really need a good map.

STEVE: "Whole new mountain ranges and valleys and things were discovered in the search for MH370 that never showed up on a map. People thought well well it should be really obvious if there's a plane on the bottom because it must just be a flat boring surface. It turned out to be you know deep ravines and crags and mountain peaks where you can easily hide a Boeing triple 7." Enter, an international group of Ocean Avengers named Seabed 2030...

"Seabed 2030..." The goal of Seabed 2030 is to map the entire ocean floor in detail by 2030. So instead of a resolution of 1.5 kilometers, they're trying to get even the most unknown areas mapped down to a resolution of 800 meters, and higher traffic areas mapped down to only a few meters. Nobody's done this before but Seabed 2030 is different in two key ways: First they're getting data from new sources. Basically, everybody, from oil and gas companies to environmental groups to militaries - with some caveats.

STEVE: "The Russians are never going to give us their high resolution map of the approaches to Murmansk Harbor and the Chinese aren't going to do the same with their approaches to Qingdao. And we wouldn't expect them to. Tut what we would expect them to do is, if they're able to say we're willing to let you have a map which is accurate to maybe 100 meters that's great. Tt's still giving us a much more detailed map than presently exists." Second, Seabed 2030 is getting data from the cutting edge ocean tech used by many of these groups.

STEVE: "There's two exciting things at the moment. First of all as I put it, the rise of the robots..." "Unmanned underwater robot" "Autonomous underwater vehicle" "Let's call it an underwater drone" "to explore underwater marine habitats" STEVE: "We call it "mowing the lawn." You're going back and forth, back and forth, just trying to go up and taking those kind of measurements which is really really dull for a human crew to do but the robots are fine. You know you can go out to the robot and say "There's your patch of ocean, go mow the lawn." And alongside the robots? AI.

STEVE: "I'm looking forward to the robots being smart enough to spot something interesting and investigate it to a higher level of accuracy." It's working! When the project, started we only had detailed maps for 6% of the ocean floor. Now? 25%. Long way to go but a lot of progress. Some people are worried about what we'll do with these maps. They think that better data might mean destruction if we find something valuable like minerals to mine, But as Steve put it: STEVE: "The lack of map is not the barrier to any of those people going out there and doing mining. You can't manage what you haven't measured and a map whether it's a map of the land or a map of the seabed, it kind of puts you all on the level playing field." Saying that we don't want information because we're afraid of what we'll do with it...

That's not what helps people. It's our responsibility to use what we learn wisely.

I think that we can't be afraid of knowledge for fear of what we'll do with it.

Humanity's ability to map our environment has always been our first step to understanding it and hopefully using it for the better. Right now, we're exploring one of the last unknown places on our planet. That's awesome to be able to do together as a species.

I think of it kind of like I think about the International Space Station: countries at odds over all kinds of political ideologies, working together for the sake of exploration and science. It's inspiring. The ocean is terrifying and beautiful and ing immense and we are these hairless monkeys, incapable of diving by ourselves 1% of the way down, who somehow through our technology and our curiosity and our grit over hundreds of years are finally now being able to see and be a part of a different world. I can't wait to see not just what it looks like and what we learn but what we build with that knowledge to continue to push our world forward.

That would be truly huge.