Field Trip: Earth

CARTER EMMART (Director of Astrovisualization): OK. Welcome. Welcome to Earth Day, 50th anniversary. My name is Carter Emmart. I'm the Director of Astrovisualization for the American Museum of Natural History. And we're celebrating the view of Earth from space. This is what gave birth to Earth Day 50 years ago, from the pictures brought back by our lunar explorers that went to the Moon in the Apollo program.

So today when we're all home and looking at the Earth together, this reminds us of our larger moment, which is the planet. And it really became obvious to us when we went out to the Moon that it was lifeless. That looking back at all the life on Earth is what matters. And this is where we are. And it's where we have evolved. And it's where all life that we know of in the universe exists.

So today what we're going to look at is this beautiful blue planet. It's blue because of the atmosphere and the way it scatters the light. And you can see the swirling clouds of weather. And also dominating our view for the most part, 3/4 of the Earth is covered by water. So we see oceans. And then also land, we see green and browns of the land.

But also the Earth spins on an axis. It spins-- imagine spinning a basketball on your finger-- is that you would balance it on the spin point. And that creates a sort of axis of rotation for the Earth. So where it spins, up at the poles, it's cold because it doesn't get a lot of sunlight. But where it's spinning around at the widest part, the equator, is where it gets the most sunlight. And so it's warm. And so what we see here is weather and the clouds, that this sets up these patterns.

I'm going to be joined today by my friend and colleague, astronomer Jackie Faherty, who's going to take questions from the Chat. And so we're here together. Jackie.

JACKIE FAHERTY (Senior Scientist, Department of Astrophysics): Hi, everybody. Yup. I'm here. I'll be monitoring the Chat and taking any questions you have about the Earth, as Carter flies you through some gorgeous parts of the Earth today.

EMMART: So thanks, Jackie. And also silently joining us is our pilot, Micah Acinapura. And what he's piloting is called Open Space. And Open Space is software that's freely available. And if you're interested in knowing more what it's about, our team is on the Chat. So you can ask questions about how to get it. And you can do this yourself.

We're looking at an image of the Earth from April 11. And it comes to us from NASA, and NASA satellite images that we direct into here. And as we get closer-- we're coming in now over South America. We're going to take a quick little tour to about five different, what we call biomes or environments of Earth. So think of mountains, or deserts, or rainforests.

And our first destination here in South America is, as you can see, as we're coming in, a lot of clouds. Can you see the white clouds? And then also to the lower right we can also see some browns. And that brown band is actually the land that's just west of the Andes Mountains mountain chain.

And so the Andes Mountains in South America, that run along the west side of the continent, actually trap the circulation of the moist air coming off the ocean in this tropical region, the equatorial region that we call the Amazon Basin, named after the great Amazon River. Basically, it's the world's largest river. It has the capacity of basically one fifth of all the river water in the world.

And as Micah brings us down lower, we're going to be seeing through the clouds essentially. So Micah, why don't we come on down through the clouds.

FAHERTY: Hey, Carter, as we go in, we've got a question on the age, as we're coming down, the age of the Earth. And if you're looking at younger or older parts of the Earth here?

EMMART: Oh, that's a good question. Well, what we know about the Earth can be inferred from some Moon rocks that we brought back in the Apollo program. They're the oldest rocks found, 4 and 1/2 billion years. And the oldest Earth rock is about 4 billion years. So we've been around a long time.

But what we're seeing here, these continents of Earth that move around, that we found out, and something-- we call it plate tectonics. But the sort of land areas of Earth move about. But as they do, and as they move and sort of collide with one another, it forces up mountains. But then also erosion happens, basically rain. It's brought up. It's moist air that comes up and drops the moisture out as rain over the mountains-- comes down.

And what it does is it erodes the mountains. And so it carries a lot of dirt and a lot of soil. And that comes into these rivers. This is the Amazon River we're chasing. Micah is-- Micah, can we come lower?

And as we do-- Micah, can you tip it over so that we see the atmosphere? And so I'm asking Micah to tip the atmosphere over. The atmosphere is really, really thin. It's only about 20 miles thin. And the Earth itself is about 8,000 miles in diameter. So really what we live in, and the atmosphere, is equivalent to about as thin as a skin on an apple.

Micah is coming into an area here in the river. Micah, let's drop down. I want to see the city of Manaus in Brazil. It's the capital of the Amazonas Region of Brazil, so the Amazon rainforest. The green that we see surrounding this area, beyond the river, is all forest. It's tremendous. It's the largest rainforest in the world, the Amazon.

But we're coming in. We see a city here. It's gray. And this is typical, the color of cities, mainly concrete. But Manaus has a population of about just over a million and a half people. It's about the size of the city Phoenix in Arizona.

So what we're going to do now is we can see actually the Amazon River. Can you see these pictures? These pictures have taken from space, and brought together, and sort of all stitched together like a big quilt. We call it a mosaic. And so sometimes you'll see pictures that maybe have a little clouds and then you might see a little border. But these are how we put this together.

And so NASA takes these pictures. Various satellites take these pictures. And we work with a company called Esri that helps us put this together. And that's what we're showing you now, up close.

But let's fly farther downriver river of the Amazon. We're going eastward through the rainforest. The rainforest is on both sides. And it's in green.

FAHERTY: Carter, as we fly away, the question is the river is always this brown or if it changes color?

EMMART: Actually, as we came down, Manaus is this area where the Rio Negro, which looks kind of dark, comes together with the brownish-looking Amazon. And the Rio Negro has less dirt in it. And it's actually clear, but looks sort of dark from space. And it flows together just east of Manaus, in this confluence of two-- of the tributary rivers that make up the Amazon.

So now we see where the Amazon drains into the Atlantic Ocean, and so the mouth of the delta of the Amazon River. And so we're now going to move back up and away from the Earth. And this green, this tremendous green, once again is because of all the rain that's come coming down off of this warm belt, right down around the middle of the Earth. That's mostly the sunlight.

And so, again, it's very warm. So it evaporates the water of the ocean. And then that flows and creates the circulation patterns that we see of the weather. Can you see the blue of the ocean, the Atlantic? We're going to fly about 2,000 miles across the Atlantic. So we're going to come across.

The width of the United States is about 3,000 miles. So the distance from New York to Denver, about 2,000 miles. So now we can see the brown of the Sahara Desert. We're coming in on Africa. And so the Sahara occupies about one third of Africa.

You can see in the lower right, we can see clouds over the Congo rainforest. So above that are these desert bands on Earth. And this is caused by-- once again, the equatorial warming causes the air to get hot and buoyant. So it goes up like a hot air balloon.

And then it starts to cool as it gets higher. And it spreads out on both sides of the equator, north and south, and creates these desert bands. So we're coming up to the largest desert in the world, the largest hot band of desert here.

I'm going to ask Micah to go a little bit farther eastward, if you can please. These are the Tibesti Mountains. And so if we go a little bit farther east, these are mountains that are built by volcanoes out in the middle of this desert.

FAHERTY: Carter, just real quick, another question here from eight-year-old Lily, which was on-- since we're on land, but it looked like there was a lot of water. The question is, how much of the Earth is land versus water?

EMMART: About 3/4-- that's a good question, Lily. So 3/4 of the Earth basically is ocean. So we live on sort of one fourth or one third roughly of the Earth that's land. And the land is divided up into deserts, and grasslands, shrublands, and forests. And so we're now coming into this portion of the Earth. About 30% of the Earth is-- of the land area are actually deserts.

So Micah is coming in over the Tibesti Mountains. And these are lava flows that were created by volcanoes. And they've been eroded. Can you see-- when I say that, they've been carved. Can you see that in these darker areas here, this is volcanic rock. And we can see this carving of it in little-- sort of river channels that have been eroded away.

This indicates to us that this area wasn't always this dry. And so about 100,000, 200,000 years ago, and during the ice ages, this was actually a greener environment. But now it's quite dry. And so the oranges-- can you see that sort of yellow orange color-- those are sand dunes.

And so this area had been carved when it was wetter. And it creates these drainages basically where the water flows and erodes that rock that comes down. And the hot winds circulate the sands. And so these sand dunes blow around.

And they're yellowish in color because sand is really made up of like glass. This is silica or sort of the crystal of silicon dioxide. It's glass. It's what we make glass out of. And glass can be clear. But it's coated a little bit with iron and that iron that weathers off. And that creates a kind of orange-reddish color.

FAHERTY: Carter, my question about something that I think is one of your favorites, which is if this looks like how Mars looks since it's so red And little Elliot has heard that that is also a rusty planet.

EMMART: Well, that's-- Elliot, thank you for asking that question. Because, in fact, I was about to mention that, that Mars is essentially a weathered planet that has kind of a rust component that makes it red, reddish-brown, very much like the Sahara Desert. When we fly over the Sahara, we can we sort of pretend that we're on Mars. But it's a lot hotter in the Sahara than it is on Mars.

So I'm going to ask Micah to now fly higher up so that we can go into some other mountainous areas that are in the continent of Asia. So we're going to be flying eastward over the Middle East. And as we elevate higher up, we can see the Mediterranean. Can you see the blue in the top left? That's the Mediterranean Sea. We don't really call it an ocean because a sea is smaller than the oceans. But it's right there between Africa and Europe.

So we're now going to pull away from the Earth. And we're going to fly eastward into Asia. What we can see as we pull back is how the atmosphere kind of comes on. We see that again. And this is from April 11.

And down below, can you see the blue that's stretching from the center, over to the right? That's the Red Sea. It flows down to the Gulf of Aden. And then we see the Arabian Peninsula. And then we're going to go farther east into Asia.

FAHERTY: Carter, a quick question from Maggie. Little Maggie wants to know if there is still atmosphere in this area or if the Earth's atmosphere is gone where we're orbiting here?

EMMART: So the atmosphere-- that is a good question, too. The atmosphere covers the entire Earth. The earth is so big that it can actually-- its gravity can just hold onto air. And that's what it does.

Our Moon doesn't really have air because it's too small. It's about one quarter the diameter of Earth. It's too small to really hold onto an atmosphere. And so the Earth has this beautiful, rich atmosphere that we enjoy.

What we're coming down on-- can you see that river valley, this sort of green river valley, the Indus River Valley, that's running to the bottom of the screen? But we now see a green band. Can you see the green band across the middle? And then also we're going to see snows or the white areas of mountains. And these are the Himalayan Mountains.

These are the tallest mountains in the world. The green that you see, in Nepal and India, is actually forests. And these forests are thanks to the water, once again from the atmosphere that flows up north. Flows up the mountains, cools off, drops off as rain, feeds these forests.

And then when it gets over the mountains, to the left, we have the Tibetan Plateau, which is a tundra. It's dry. It's sort of a desert of itself, high desert.

And so Micah is bringing us down across the top of the Himalayas. And these snows build up. So here we have snow.

And when it melts, it runs off. First, it flows in ice glaciers, alpine glaciers. So the ice flows downhill. But then that melts off into the rivers that come off the Himalaya. And the major rivers of Asia come off of this mountain chain. And it feeds-- basically, the water is responsible for feeding over 3 billion people, India, China, Southeast Asia.

And so now we're coming in to an area where these mountains are the highest in the world, the Himalayas are. And Micah is going to bring us to the highest mountain. Maybe some of you have heard of it. It's called Mount Everest.

And as we come in-- now, can you see that sort of gray little fingers that are coming off the snows here? Those are glaciers. And that's ice that builds up. And actually ice kind of flows. It flows slowly, but it flows down. And when it does, it sort of carves these valleys. And it sculpts the mountains that we see. The Himalayas are still--

FAHERTY: Carter, a question-- before we get in, there's a question from Max and Maddie. And they want to know if we've been also flying over little lakes, too, as we've been going over the mountain?

EMMART: Well, we saw lakes in the Tibetan Plateau. There are tiny lakes up here. So some of them you see. And you'll see them kind of bluish color.

But also these mountains are still growing. They're growing about half an inch per year. Why are they growing?

Well, the whole continent of India-- a smaller continent started to collide with Asia as a continent after the death of the dinosaurs. And they died off. Dinosaurs died off about 60 million years ago. But about 40 to 50 million years ago, these two land areas came together. And they're still colliding, forcing up these mountains.

Micah, let's come closer to Mount Everest. This is beautiful. I want you to drop down lower if you can. We are now to the north of it. That's why we see the sort of shadow from the Sun. And we're looking across the beautiful greens of Nepal and then across, out to India.

And so this is the tallest mountain in the world. And this is a good way to get there, is to fly in Open Space and see it this way. And you might wonder. These pictures are taken from space. But they also-- from space, we can actually get-- an elevation map, we call it.

In other words, we can get the shape of the mountain. And then the picture is put on top of that. So everything you're looking at is basically data that we've gotten from our space program and satellites. And we put it together into this big map.

FAHERTY: Carter, as we fly away, one of my favorite questions-- little four-year-old Eleanor says her mom really wants to hike Mount Everest. Have you ever seen people in any of these images?

EMMART: We can see people. And we don't see anything-- I haven't seen any people in the pictures of Mount Everest. But where the pictures are good enough-- and it varies in quality. So if you come into a place-- well, like in Mecca you can see the people around the Kaaba, which is the black cube that is worshipped in Islam, is full of people. Tiananmen Square in China, you can see people. And I think I can see people, indeed, in Washington, D.C.

So here we see the mountains of the Himalayas. And also this is the great Brahmaputra River. It flows together into the Ganges. And it's one of these river systems that come off the Himalayas.

So now we're flying up-- Micah is going to turn to the right. And we're going to fly down across Southeast Asia, the various countries there, and a favorite part of the world for me. Micah is also-- we're going to just adjust the timing. In other words, we're looking at lighting because the Earth spins day and night. So in the software, we're going to-- rotating the Earth to see the lighting change.

So here we are-- down below us Southeast Asia. And then we're coming-- we're aligning ourselves, so that we're going to come down to Australia. And Australia is a continent about-- it's the smallest continent. But it's about the width of the United States, about 3,000 miles wide. And it's south of the equator.

So the most northern reach, which is closest to the equator, is tropical. And so again we have rainforest in the Queensland area of Australia. And off of that east coast, that northeast coast of Australia, is the largest reef in the world. And this is basically a barrier island chain, which is created basically from shells.

This is life. Over about 10,000 years that life has been building this reef system. And so it basically is a sort of boundary area between land and the oceans. And reefs are responsible for where all our-- a lot of the fish that we eat are actually born. And it's home to thousands of species.

So it's very important for us in how we interact with the Earth. And Micah is going to bring us in closer. We rely, of course, on the Earth, whether we eat only plants or whether we eat plants and animals. We are of the Earth. We're part of this whole ecosystem. The beauty of looking at the Earth this way is that we see the Earth for what it is.

Here, this is called Cape York up there, those beautiful blues, that sort of blue and turquoise water. And then we begin to see the lighter blue. Can you see the lighter blues in here? And they amount to sort of a chain of islands. And these are the barrier islands that sit off the northeast coast, up by Queensland, Australia.

FAHERTY: Carter, a question-- we coming in here. I think it's a nice one, from Charity. Which is, if there's also-- this is such a wet area. Is there also a rain forest in this area, in Australia?

EMMART: Yes. And I mentioned that Queensland is a rainforest because it's the most northern part of Australia. So it reaches up into the tropics. That island just north, Cape York, I was pointing out, it's sort of in the upper left area-- is basically the island of New Guinea. So it's rainforest on New Guinea and also in the Queensland Peninsula, that's sticking out there. And the green that you see is really green because of the forest and the tropical rainforest.

So we've gone over these various biomes, so the rainforest of Brazil to the rainforest of Queensland and the Great Barrier Reef off of Australia. Of course, we've seen the mountains of the Himalayas and the Sahara Desert. But as we pull out slowly here, we're going to see the clouds come together and completing our sort of picture of the Earth.

And I'm going to ask Micah, as we as we do this movement away from Earth, is that we're going to go into the night side of Earth. When we go into night, we'll be able to see our city lights. And so the city lights show where humans are. It shows where our cities are. It shows where we are.

And so as we pull away from Australia, again we can see the swirly nature of the clouds, so the weather. Again, that's all set up because of the day/night cycle of Earth. When the Earth rotates, the night side is cooler. It comes around into the day side. It warms up from the Sun. We have evaporation of the oceans. And then that goes up higher in the atmosphere, cools off, creates the clouds.

There we can see India beneath us. We're going to come around. And Micah, can we go into nighttime here, if we could? So he's going to rotate the Earth.

FAHERTY: Carter, as we're kind of coming down, I know we had one before. But we're getting a lot of questions in the Chat on size. So could we remind people-- Riley and Rory are actually asking this right now, about how big is the Earth? Can we tell everybody?

EMMART: So it's 8,000 miles in diameter. It's very big. And think about that. In math class, if you take a diameter of a circle and multiply times 3.14, which is pi, you get the circumference of the circle. So 8,000 times 3 is 24,000 miles around. And we rotate in 24 hours.

We're now looking at-- Micah has come down over a beautiful-- almost the shape of a rose. You see that. It's almost like a stem going up to a rose. Well, what that is-- we are looking at the city lights now of humans.

And in this case, that rose pattern is basically-- the stem is the Nile River Valley. And there are almost 100 million people that live right here in Egypt. This is Egypt. And where it fans out, making the rose, is the Nile River Delta.

And you can see where the stem connects with the top of the rose there and it's kind of brighter. Micah, let's move in a little bit. That's where most of the people in Egypt live. And that's the city of Cairo.

And then just off to the right of the rose is-- we can see the coastline of Israel, and further up into Lebanon. And we see cities of Jordan and Syria. And over-- so Micah is moving in closer now. And so we're going to see some of these city lights. So we see the patterns of where we live, basically because we light ourselves up at night.

FAHERTY: Carter, we had a question from Matteo, which is an interesting question. Do people ever live on the water there?

EMMART: Well, people live-- it's a good question. Do people live on the water? In some communities around the world, yes, they do. But they live typically close to land because-- of course, cruise ships and things like that go out onto the ocean.

But few people actually live out there on the ocean. We live typically close to water. And notice how everybody was living along the river. Well, that's because that's where the water is.

So Micah is now flying a little bit westward, which is nice. We see the lights of Turkey in the upper right; the lights of Athens, right in the middle of the screen there now. But then coming into view, can you see the sort of shape that's coming up? And it's rather distinct. It kind of looks like a boot.

And that boot is the boot of Italy. It's the shape of Italy. We can see the night lights sort of outline that. And the two bright spots you can see along the boot, or maybe the boot buckles, are Naples to the right. And farther up is Rome. And even farther up is the city of Milan and the Po River Valley that flows into Venice and Florence-- all these beautiful places there in Italy.

So we're going to bring the day back around. And we're going to finish up by going up to a polar region. And we've talked about the hot desert of the Sahara, around the equator. But look at the poles. Even though they're ice covered, that it's actually quite dry because of the way the atmosphere flows.

It goes up to the pole. It basically cools off. And then it comes-- because it cools off, it gets heavier. Then it comes down and sweeps out, winds, and sort of dries off that ice. So what we're going to do now is we're going to come in-- coming north. And we can see here in this image--

FAHERTY: Carter, as we come down, too, because it's such a beautiful part of the Earth, we've had a lot of questions about the shape of the Earth. And Lanier is asking if the Earth is a perfect circle or not? It's such a good view from here, to talk about that.

EMMART: It looks like a perfect circle. If you're a geophysicist-- that's how I was trained through my undergraduate years-- it's not a perfect sphere. And we have this concept called the geoid, which is sort of the shape of the planet. But from where we are and how we see it, it's nearly a perfect circle, a circular shape, spherical shape. But that's a really good question because it does vary. And, of course, the mountains are bigger here and there.

So we're looking now at the continent-- or the sort of subcontinent of Greenland. OK. All right.

FAHERTY: Maybe while we wait, since we're now waiting for our Earth to come back up, I can shoot you a couple more. We've had a very, very active chat with people--

EMMART: That's great.

FAHERTY: --in here. And some off-the-wall questions, that I'm going to throw a couple of them at you.

One from Matteo, who's 4. Do you know how-- can you explain how gravity works, how people are kept on the planet?

EMMART: So, boy, that's-- gravity is one-- this is a great question. We can describe how gravity works. In other words, we understand that gravity happens because if you have a lot us stuff somewhere, like the Earth, that attracts other stuff. And we're small stuff. So we'd stick onto the big stuff. So the Earth is big. And you can jump up and down and try and get away from Earth. But it really takes a rocket to get away from Earth.

So what we understand is more stuff has more gravity. Why it has gravity, we don't really know. That's a real good question. And some of the greatest physicists in the world have thought of this question. We wonder why? Why does gravity happen?

This is kind of a mystery to us. But how it works, we can describe in great detail. And we that by experiments.

FAHERTY: It's a good point. And as astronomer, we think about gravity a lot. Oh, it looks like we've got our planet back on.

EMMART: So the eastern coast of Greenland-- and every year at this time, in spring, the ice sheet begins to melt at the edges. And so the ice starts to come off in chunks. And if we come in close-- Micah, this is great-- we're going to actually see chunks that are almost the size of cities, that are breaking off. And these become icebergs. And they begin to float around.

Now, you also see a lot of things. There's a lot of white. You see the blue. The blue is the ocean. But what we see are clouds. Clouds are white. And we also see the ice of-- the ice sheet of Greenland, which is in the upper left. And so that's like snow.

And then we can kind of see some mountains in here. And we can also see-- again, we can see valleys that have been shaped by glaciers and by meltwater. But then also the finest detail that we see in these little, swirly patterns is actually ice floating on the ocean. So the difference between the clouds and the ice, the ice sheet, it's all white. It's kind of like trying to tell-- you've got a polar bear in a snowstorm. It might be difficult because they're both white. But in this case, we can see this. And that creates these beautiful patterns that we see every year at this time.

FAHERTY: Carter, on this cue we had several people ask questions. The last one I saw came from JD on whether or not the Earth could get bigger? And seeing the glaciers break off and contributing to the ocean might be a good point to talk to JD and the others about that.

EMMART: So it's interesting. The Earth doesn't get bigger. It was sort of formed billions of years ago, about 4 and 1/2 billion years ago. And so the stuff that we have of the Earth is here. We have occasionally things fall to Earth. In fact, last night I guess is the Lyrid meteor shower.

And so we still collect stuff because we-- again, we have big gravity because we're big. And so stuff is attracted to us and falls in occasionally. So we get slightly bigger by those things falling in.

But we can get bigger if we have a lot of stuff falling on us. But that really happened in the formation of the Earth. But since then, we've been dealing with what we got. And so this budget of different things, that the lighter stuff kind of rose to the top, and the hot dense core in the middle, actually creates a magnetic field. And we're not seeing that. Join us later today when we talk with Professor Martha Gilmore about what makes Earth so special-- but our magnetosphere that's created.

But what we're seeing here right now is the air. We can see-- that beautiful blue edge to the Earth, it's from what we call the scattering of the light from the oxygenated atmosphere. We're really about-- sort of 3/4 of our atmosphere is nitrogen, about 20% is oxygen. But that oxygen creates is beautiful blue glow. And that's reflected in the ocean. So we really do call Earth the blue planet.

And we're coming back now. Micah is lining us up. So that we can finish off this program, coming into where Jackie, and I, and our team come from, from the American Museum of Natural History. So we're going to close in to New York.

And when we do this, remember at the beginning of the program I showed you a city. We saw briefly the city of Manaus, out in the middle of Brazil. And it was kind of gray. And it's gray because concrete roads, buildings, things like that. And as Micah comes in closer now, what we see is-- we can see the green of North America.

Notice that light blue that we see in the ocean. And then it gets darker blue. That's because there's something called the continental shelf. So we're seeing lighter blue where the ocean is not as deep. And then deeper blue in the lower right now, from where it falls off into the abyssal depths of the ocean.

Now, we're coming in. We can see Long Island. Can you see Long Island? It's sort of stretching from the middle. Micah is centering in on the gray patch which is New York. And in the upper right, we see Cape Cod. That's where I'm sitting and talking to you from. And also Boston is just off the top of the screen up there.

But now as we come into the head of the sort of fish-shaped Long Island, we could see the five boroughs of New York. We see Connecticut. And we also see New Jersey. That's where I grew up.

And so we come in closer now. And we see this beautiful harbor-- it's an amazing harbor, and the Hudson River that runs north. And the city grew because this harbor was a goldmine for transport of all the riches of the New World several hundred years ago.

Now, we come in. We can see Brooklyn to the lower right. We can see the island of Manhattan. And it's between the Hudson River and the East River. And as we come in closer, we might be able to see some darker patches at the tip-- of the southern tip of Manhattan. That's where all the tall buildings are.

And again, Midtown, all those tall buildings in New York City right there, in Midtown, it makes it kind of darker because of the shadows. But we also see Central Park. And also can you see the blue in the middle of Central-- Central Park is green. And it forms a rectangle dead ahead of us.

And then off-- you can also see Roosevelt Island. That's that long, little island in the middle of the East River over there. But in the middle of Central Park, can you see that blue? There's a sort of blue thing. That's called the reservoir.

FAHERTY: Carter, if I could just jump in for second because I know we're just right at our edge of time.

EMMART: OK.

FAHERTY: I want to give one shout-out here as we look at Manhattan, with this beautiful grid, to the event that happens-- starts to happen in Manhattan in one month. Right now the Sun is getting itself-- and we're getting in ourself-- in a position where we're going to have a line up a setting Sun, with this beautiful grid of Manhattan, for an event we call Manhattanhenge, which hopefully will be able to celebrate. It's always wonderful to see the grid and the view here. I know where we're at our 12:40 breaking point.

EMMART: I'll just do one last point. The George Washington Bridge, which is out there in the background, is exactly one mile. So the Hudson River is about a mile wide. And Central Park is just a little shy of that. But right in the middle is the American Museum of Natural History, our home, and the home of this proper Open Space.

I want to give a shout-out to our colleagues in Sweden, who help us to develop this. And also to our NASA support, that has helped us build Open Space and bring it to you today. And it's been a lot of fun, hasn't it Jackie? It's fantastic.

FAHERTY: It's been great. I know we had students from all over, Montclair Kimberlee Academy, Lockhart Air Academy, I know you both were in the Chat. Thank you for joining us, kids. And you can look forward to more educational content from the museum all day long, including an event we're going to do in the evening at 6:00 o'clock for those that want a little bit more on Venus and Earth.

And tune in right after this for a super-cut video on Earth Day that you can watch from the American Museum of Natural History.

EMMART: Thanks, Jackie. And thank you all.