NOVA scienceNOW : 53 – Sleep, First Primates, Earthquakes in the Midwest, Profile: Sang-Mook Lee

NOVA scienceNOW : 53 – Sleep, First Primates, Earthquakes in the Midwest, Profile: Sang-Mook Lee


NEIL DeGRASSE TYSON (Astrophysicist/American
Museum of Natural History): On this episode of NOVA scienceNOW: Everybody knows earthquakes
happen in places like California, but there may be a looming threat where you least expect
it. Memphis, Tennessee? That’s right; land of
Elvis, barbecue, and Beale Street. These folks don’t look too worried, but maybe
they should be. Some of the most powerful earthquakes in history happened right under
their feet. Now, geologists are deep underground, uncovering
a frightening pattern. BRUCE FOULKE (University of Illinois at Urbana-Champaign):
And that layered stalagmite is what lets us recreate the timing of earthquakes. NEIL DeGRASSE TYSON: Could the next big one
strike America’s heartland? Also, why are these fruit flies being rolled
and bumped on a machine called the deprivator? It’s all in the name of sleep research. MATTHEW WILSON (Massachusetts Institute of
Technology): Sleep is an enigma. What is its purpose? That’s something that we do not understand. NEIL DeGRASSE TYSON: But new studies indicate
that one purpose of sleep may be to help us learn, that while we snooze, our brains replay
memories, maybe even editing and enhancing them. ROBERT STICKGOLD (Beth Israel Deaconess Medical
Center): When we wake up in the morning, in some way, we have a different brain. NEIL DeGRASSE TYSON: And in our profile, you’ll
meet “the Stephen Hawking of South Korea.” SANG-MOOK LEE (Seoul National University):
He looks into the universe; I look into the bottom of the sea. NEIL DeGRASSE TYSON: A geophysicist and professor,
struck down in his prime. SANG-MOOK LEE: My van flipped, I was crushed. NEIL DeGRASSE TYSON: He struggled for acceptance
in a society that shuns the disabled. SANG-MOOK LEE: People with disabilities tend
to hide in a shadow. NEIL DeGRASSE TYSON: Fueled by his passion
for science, he fought his way back, inspiring others to overcome their disabilities. SANG-MOOK LEE: I ask myself, “What can I do,
actively, to give back?” NEIL DeGRASSE TYSON: All that and more on
this episode of NOVA scienceNOW. SLEEP
NEIL DeGRASSE TYSON: Hello. I’m Neil deGrasse Tyson, your host for NOVA scienceNOW. We all know that dreams can be, dreams can
be a little weird, sometimes filled with bizarre events that would never happen in real life.
Nobody really knows why we dream. In fact, nobody really knows why we sleep. Here are some folks who are trying to figure
it out. Amita Sehgal likes her flies, fruit flies,
to be precise. AMITA SEHGAL (University of Pennsylvania and
Howard Hughes Medical Institute): I do have a genuine affection for them. NEIL DeGRASSE TYSON: But sometimes, she has
a strange way of showing that affectionóespecially, when she puts them into this thing. AMITA SEHGAL: We use this piece of equipment
we call “The Deprivator.” NEIL DeGRASSE TYSON: The Deprivator? It’s
like riding a roller coaster during an earthquake. What’s interesting to Sehgal is what the flies
do after spending a whole night in here. The flies on the left were undisturbed last night,
and they look fine. But the flies on the right, they were jostled all night long in the Deprivator.
Now, some of them look dead, but they’re not. According to Sehgal, they’re catching up on
lost sleep. AMITA SEHGAL: If we keep flies awake at night,
they need to make up for the sleep they have lost, and so will sleep in the morning, at
a time when they’re normally active. NEIL DeGRASSE TYSON: But why would flies need
to sleep? Could it be for the same reason we need to sleep? Maybe. But if you ask an
expert what exactly that reason is… MATTHEW P. WALKER (Harvard Medical School):
We actually know very little about what sleep is doing for the brain. AMITA SEHGAL: We spend a third of our lives
sleeping. If you don’t sleep, you die. MATT WILSON: Sleep is an enigma. What is its
purpose? That’s something that we do not understand. NEIL DeGRASSE TYSON: Looks like a waste of
time. But then why would so many creatures do it? MATT WILSON: Sleep is something that, the
more we look at it, the more we see that it is fundamental. It’s fundamental to essentially
all organisms. NEIL DeGRASSE TYSON: Including, it seems,
organisms like fruit flies. When they’re not being knocked around all night, Amita Sehgal’s
flies follow a pretty familiar schedule. AMITA SEHGAL: They’re active during the day
and they sleep at night, for the most part, although there is an afternoon siesta as well,
especially in males. NEIL DeGRASSE TYSON: Trying to pinpoint the
reason for a fly to snooze up to 12 hours a night, Sehgal’s lab studies the fruit fly’s
brain. AMITA SEHGAL: What we were doing was trying
to figure out which part of the fly brain was important for sleep. NEIL DeGRASSE TYSON: Sehgal’s experiments
pointed to the mushroom body, a part of the brain found in creatures like insects and
spiders, but not in humans. Biologists have known about the mushroom body for years, but
they associated it, not with sleep, but with something else entirely, an insect’s memory. AMITA SEHGAL: There is, then, this structure
in the fly brain, which we already knew was required for memory, and we now find that
it controls sleep. NEIL DeGRASSE TYSON: The finding’s intriguing
because, for a long time now, sleep researchers have been debating a possible connection between
sleep and memory. Bob Stickgold has been looking into this possibility,
sometimes in unconventional ways. For him, video games are research tools that can help
reveal how our brains learn. ROBERT STICKGOLD: Do you remember, when you
first started playing TetrisÆ,… NEIL DeGRASSE TYSON: Oh, yeah. ROBERT STICKGOLD: …that you went to bed
at night, and you lay in bed, and you closed your eyes, and you saw little Tetris pieces
floating around in front of your eyes? NEIL DeGRASSE TYSON: How did you know that?
How did you know that… ROBERT STICKGOLD: Because… NEIL DeGRASSE TYSON: …I dreamed Tetris shapes? ROBERT STICKGOLD: …because everybody does. NEIL DeGRASSE TYSON: After taking a few rides
on a ski machine, Stickgold’s research subjects fall asleep, and then he promptly wakes them
up. ROBERT STICKGOLD: If we wake you up just two
or three minutes after you fall asleep and ask you, “Neil, what’s going through your
mind?” You’ll say, “Seeing those suckers somersaulting down when I crash.” NEIL DeGRASSE TYSON: And why would I dream
of this embarrassing moment? Stickgold is convinced that while you sleep,
your brain is reviewing what you’ve learned and strengthening your memories. ROBERT STICKGOLD: The brain is being modified
while we sleep, so that when we wake up in the morning, in some way, we have a different
brain. And it’s a brain that functions better. NEIL DeGRASSE TYSON: At least it seems to
function better on some kinds of memory tasks. Recent studies show that after a single night’s
sleep, sometimes even after a nap, we can do a better job recognizing visual patterns
and even solving some math puzzles. MATTHEW WALKER: What we’re going to have you
do is try and type out a short, five-digit sequence. NEIL DeGRASSE TYSON: I saw it first-hand when
I took a simple typing test, typing a string of five numbers over and over again, as fast
as I could. After a night’s sleep, I could suddenly type
the numbers faster and more accurately. And research backs this up. Most people improved
their typing by about 20 percent after sleep. MATTHEW WALKER: Practice doesn’t make perfect.
It seems to be practice with a night of sleep that makes perfect. Sleep is enhancing that
memory so that when you come back the next day you’re even better than where you were
the day before. NEIL DeGRASSE TYSON: But exactly how could
sleep enhance your memory? We don’t know. But possible clues have been showing up, not
just in the brains of flies, but in the dreams of rats. M.I.T. researcher Matt Wilson says he can
read rats’ minds, including their dreams, with tiny electric probes. MATT WILSON: What it means is that we’re able
to, at any time, plug in our electronics, and… NEIL DeGRASSE TYSON: Figure out what they’re
thinking. MATT WILSON: …read their, read their mind. NEIL DeGRASSE TYSON: Wilson’s mind-readers
are actually thin wires, about a tenth the width of a human hair, that pick up the electrical
signals among dozens of brain cells. The wiresópainlessly implanted in the rat’s
brain and held there by a kind of hatócarry the signals right into Wilson’s computers. That information comes up back through these
connectors into your computer, and you’re sitting there watching a map of the thoughts
of this rat? MATT WILSON: Exactly. That’s exactly right. NEIL DeGRASSE TYSON: It’s remarkable. Wilson is most interested in mapping the rat’s
thoughts in a part of the brain called the hippocampus. Like the fruit fly’s mushroom
body, the hippocampus of a rat or a human plays an important role in memory, including
our sense of space and location. Wilson uses a specially designed rat maze.
If the rat follows the right route, he’s rewarded with some chocolate syrup. And as he moves
through each different spot in the maze in search of his goal, a unique pattern of cells
fires in his brain. MATT WILSON: So we can tell where the animal
is, simply based upon which cells in the hippocampus are active. That pattern will be unique for
a given location in a given environment. NEIL DeGRASSE TYSON: What’s amazing is that
the same patterns turn up again, even after the rat drifts off to sleep. That’s right, Wilson eavesdrops on the rats’
dreams. And they aren’t about cheese, they’re about running the maze. MATT WILSON: So when the animals would go
to sleep, we would see these patterns of brain activity that were expressed while the animals
were running on the maze, being replayed, in the same sequence, the same order in which
they had been experienced. NEIL DeGRASSE TYSON: But the replay wasn’t
exactly the same as when the rat ran the maze. Sometimes it was like an extreme fast-forward;
quick flashes of the experience. MATT WILSON: Now, at the time, you never know
what is going to be important and what is not important. So you may re-evaluate or edit
those memories to identify the things that were important. NEIL DeGRASSE TYSON: And this fragmented replay
wasn’t just happening in the hippocampus. Wilson also detected it in the visual cortex,
meaning the rats were likely seeing the maze in their sleep. What’s more, the visual cortex is part of
the larger neocortex, which, in humans, is responsible for, among other things, long-term
memory. MATTHEW WALKER: The hippocampus is replaying
the events of the day. The hippocampus is almost, sort of, reactivating the memories
at night and playing them out to the neocortex. It’s almost as though the hippocampus is having
a therapy session with the, with the neocortex. And it’s almost saying, “Okay, here’s what
we learned during the day.” MATT WILSON: What are rats and what are people
doing during sleep? They are processing memory. They are replaying memory. Now, we could ask,
“Is this about learning?” And I believe that’s exactly what it is about, that animals are,
and humans, are trying to learn from past experience. NEIL DeGRASSE TYSON: So, the idea here is
that the sleeping brain might be reviewing and strengthening new memories it wants to
hold onto for the long-term. And it might identify certain goals we want to work towards. So could it be that “sleeping on it” isn’t
just an old saying, but a biological process that consolidates and organizes important
information? MATT WILSON: These are pretty big concepts.
And they certainly are controversial. The function of sleep, as it relates to learning
and memory, that’s something that, at this point, remains speculation. We’re making a
leap. NEIL DeGRASSE TYSON: Not everybody is leaping
into bed with this idea. And researchers have a long way to go before they know what sleep
is really doing for our brains. But if the speculation turns out to be true, then you’d
have to wonder, “What is our 24/7 culture doing to our ability to think straight?” MATTHEW WALKER: Sleep is not just something
that we can choose to sort of dabble in every now and again. It’s not a luxury; it’s a biological
necessity. MATT WILSON: My sense is that disruption of
sleep is much deeper than simply, you know, robbing us of rest. My guess would be that
we lose the opportunity to gain understanding, a deep understanding of our past experience,
that what we sacrifice, in a sense, is wisdom. FIRST PRIMATES
NEIL DeGRASSE TYSON: As inhabitants of Earth, we humans are relative newbies. In fact, our
branch of the evolutionary tree may have split with these apes only about 6,000,000 years
ago. But what if we look further back in our primate
family tree? There must have been some great and wise ancestor who founded this wonderful
line of creatures, right? Well, as correspondent Peter Standring reports, the latest research
is revealing that our origins may have been quite a bit humbler than we thought. PETER STANDRING (Correspondent): The Badlands
of Wyoming: some of the largest dinosaur bones, ever, were found right here. But University
of Florida paleontologist Jonathan Bloch is hunting for a set of bones that are nothing
like the giant bones of T-Rex. JONATHAN BLOCH: Here’s a little piece of bone
here. Here’s a little piece of bone. I think that’s a little vertebra. PETER STANDRING: Tiny mouse-sized bones, buried
in limestone, that just might be the fossil remains of our earliest primate ancestors. An age-old mystery surrounds the origin of
primates. No one knows exactly where we come from or how we got our evolutionary start. Here’s what we do know: giant dinosaurs once
ruled this basin, where they dined freely in a lush forest. But then, around 65 million
years ago, the dinosaurs die off when a massive comet slams into the planet. Ten million years
later, something extraordinary happens. The fossil record suddenly shows a new kind of
mammal, with unique characteristics: the primate, our ancient ancestors. So what is a primate? What is it that separates
us from the rest of the evolutionary pack? Well, maybe it’s our good looks or our superior
intelligence. The truth is brain size does come into play.
We primates, even Noah here, have larger brains than our mammal relatives. It’s a feature
that evolved to help us learn complex social behavior and how to do things like make tools
or even outwit our prey. We also developed forward-facing eyes with
stereo vision. It’s a feature that allows us to judge the world around us in 3D. Over
time, we also developed the ability to leap, basically to jump from branch to branch, where
grasping hands, or in Noah’s case, grasping feet, equipped with nails instead of claws,
enable us to reach that tasty piece of fruit. Our earliest ancestors developed these unique
characteristics, some time after the extinction of dinosaurs. The question is, “When and why?” So let me get it straight. If the dinosaurs
became extinct 65 million years ago, and then primates suddenly appeared around 56 million
years ago, what happened in between? I mean that’s almost 10 million years that’s unaccounted
for. JONATHAN BLOCH: Right. That’s the $6,000,000
question. And I don’t think they just appeared on the face of the planet, they evolved. PETER STANDRING: But from what? I mean, something
the size of a mouse? JONATHAN BLOCH: Exactly. PETER STANDRING: Jonathan believes the evidence
to support his theory and help solve this ancient primate mystery can be found here,
hidden inside the limestone of the Bighorn Basin. JONATHAN BLOCH: A tiny little piece of broken
bone can connect up with an entire skeleton of a mammal. This looks like a pretty good limestone. It
should be…should be full of fossils, but we really won’t know until we get it back
to the lab. You see a tiny little piece of bone, and you
hope that there’s more inside, you have no guarantees, so it’s a little bit of a gamble. PETER STANDRING: But a gamble worth taking,
because these stones might hold ancient clues. Back in his lab, Jonathan, along with graduate
student Doug Boyer, gets to work. Their goal? To free the delicate bones from the rock-hard
stone. They begin by placing the limestone under a microscope. JONATHAN BLOCH: That immediately starts to
open up the world of the block. We identify all of the bone that’s outcropping on the
surface. PETER STANDRING: Doug carefully coats the
tiny bones with plastic to protect them from the powerful acid bath they’re about to take. DOUG BOYER (Stony Brook University): We leave
the block in acid for, at the most, two to two and a half hours, and that’ll remove about
a millimeter-thick rind of limestone. JONATHAN BLOCH: We repeat the process, again
and again and again and again, until all of the bone is exposed. PETER STANDRING: Much to their surprise they
find hundreds of tiny bones. Doug devises a method to meticulously document
the relationship between each and every bone. The process will take months, but when complete,
it will reveal far more than they ever anticipated: dozens of tiny mammals never before seen,
including these three extraordinary skeletons. And what are these? JONATHAN BLOCH: These are plesiadapiforms. PETER STANDRING: Plesiadapiforms are tiny
mouse-like creatures that lived during the mysterious 10-million-year period between
the extinction of dinosaurs and the appearance of primates. It’s a very diverse group, with
more than 120 species, including these three. JONATHAN BLOCH: They represent the most complete
skeletons of plesiadapiforms known in the world. PETER STANDRING: An extraordinary find, for
sure, but will they help Jonathan solve this primate mystery? Are plesiadapiforms our earliest
ancestors? JONATHAN BLOCH: If we look here, this nail-like
structure makes you think, because the presence of a nail is a hallmark characteristic of
living primates. PETER STANDRING: This is an enlarged image
of the extraordinary nail Jonathan found. Next to it, the claw he expectedóa startling
difference. JONATHAN BLOCH: This nail might actually be
the first nail in the history of primate evolution. PETER STANDRING: Concrete evidence to support
his theory of primate evolution. Could there be more hidden within these tiny bones? To find out, Jonathan enlists the help of
Mary Silcox, evolutionary anthropologist at the University of Winnipeg. She’s been busy
zapping primitive skulls with an industrial-strength CAT scanner, large enough to fill an entire
room. Mary takes the skull of one of the limestone skeletons and prepares it for scanning. MARY T. SILCOX (University of Winnipeg): The
x-ray goes through the specimen, and we collect 2,400 separate views, which produce a cross-sectional
image. A structure that had been identified as just
a little piece of bone in the middle ear actually had the form of a tube. And the reason that
was exciting was because there’s a structure running through the ear of particularly primitive
primatesóthings like lemursówhich is a tube for a large vessel that goes to the brain. PETER STANDRING: A tiny tube, a tiny nail,
the evidence is mounting. But to prove his theory of primate evolution, Jonathan still
needs more. He adds another member to the team. Eric Sargis, professor of anthropology
at Yale University, and the world’s leading expert on tree shrews. Why a tree shrew expert?
Scientists believe that tree shrewsóa primitive species of tiny tree-living mammalsóare actually
related to early primates. ERIC SARGIS: Tree shrews are not primates,
but they’re close relatives. They share a number of characteristics that separates them
from other groups of mammals. PETER STANDRING: Would plesiadapiforms pass
the ultimate primate test? Are they the first step on the primate family tree or just another
relative on the tree shrew family tree? The team goes to work bringing together all
the information they had collected independently into a single comprehensive study. Detail by detail, feature by feature they
comb through all the data using a numerical system to compare and contrast. JONATHAN BLOCH: After we studied the different
characteristics of these animals, and reduced them down to numbersóyou know, absence of
a nail is a 0, presence of a nail is a 1ówe then ran this through a computer algorithm. PETER STANDRING: Using this information, the
computer was programmed to create family trees illustrating the potential relationships each
mammal has to the next. The team expected the computer to come up with several possible
scenarios in the form of several possible family trees. Instead, the program came up
with only one. JONATHAN BLOCH: I was a little surprised to
see it so unambiguous. PETER STANDRING: This single family tree could
lead to only one conclusion. JONATHAN BLOCH: I think the evidence, as it
stands today, is pretty compelling that yes, in fact, these are primates. MARY SILCOX: Every new piece of data that
we had coming out of our study of this material seemed to be consistent with that idea. PETER STANDRING: Not only that. One of the
plesiadapiform skeletons Jonathan and Doug painstakingly etched out of limestone, a species
by the name of Dryomomys, turns out to be far more primitive than the other two, possessing
only one primate characteristic, the shape of its teeth. ERIC SARGIS: It’s sort of a transitional specimen
between more primitive things, like tree shrews, and later primates. PETER STANDRING: One part primate, other parts
not. ERIC SARGIS: I mean, it really starts to tell
us something about the base of the primate tree, what the earliest primates look like.
So, if we’re one leaf on the branch, so are chimpanzees, gorillas, orangutans, among apes;
all the different monkeys in the old world and the new world; lemurs from Madagascar;
lorises and galagoes; all those animals are living today, but you can trace it all back
to a single common ancestor. And as you get closer and closer to that common ancestor,
dryomomys is one of the animals that’s closest to the base there. It’s the most primitive
primate skeleton ever found, to date. PETER STANDRING: Jonathan had evidence to
support his theory. Primates didn’t just appear on the planet, they evolved over a 10-million-year
period. And just as he thought, the earliest primates were the size of a mouse. Still one
question remains. What sparked this amazing transformation? The team believes our ancient
ancestors evolve on the heels of a mass extinction. Without the mighty T-Rex around, the tiniest
of mammals are free to forage and explore, and they discover a world filled with flowering
plants and succulent fruit. With tempting fruit growing at the end of
tiny branches, our ancestors have plenty of motivation to change. So they begin to evolve,
developing long fingers for climbing trees, specialized teeth, hands and feet, uniquely
designed for grasping and eating the tiniest, tasty berry. Over 10 million years, they slowly
develop unique characteristics that we recognize in our primate relatives and ourselves. ERIC SARGIS: So that if plesiadapiforms don’t
evolve, we’re probably not standing here talking about this right now. EARTHQUAKES IN THE MIDWEST
NEIL DeGRASSE TYSON: We’ve got a pretty good idea of what causes earthquakes in places
like California. It’s all about movement along the big cracks in Earth’s crust. North America
is part of a giant rigid plate of crust moving this way, and the Pacific Ocean sits on another
plate moving this way. Most of the time, the edges are just kind of stuck together, but
every now and then, the tension gets too high…boom! The edges slip; you get an earthquake. So you might think, “Hey, if I just stay away
from here, I can avoid the big shake up.” But not so fast. As correspondent Peter Strandring
reports, they’re now realizing that there’s another kind of quake. It’s big, it’s dangerous,
and it could be headed straight for the middle of America. PETER STANDRING: Sam Panno is on the hunt.
He’s looking for evidence, hidden deep inside a cave in Illinois. There’s over 14 miles
of wet, slippery, bat-filled tunnels down here. After hours of hiking, he spots what he’s
come for. SAM PANNO (Geochemist, Illinois State Geological
Survey): Looks good. PETER STANDRING: These lumps of rock might
not look like much, but for Sam, they could help answer a frightening question: “Is the
American heartland about to be hit with a cataclysmic earthquake?” When I think earthquake, I think California,
the San Andreas Fault and fears of “the big one.” And that makes sense, because most big
earthquakes happen in places like California, where big plates of the earth’s crust collide
with each other. But if you ask the experts, they’ll say one of the biggest looming earthquake
threats in the US is far from California. In fact, it’s here, in Memphis, Tennessee. It’s Saturday night, and the crowds on Beale
Street seem pretty, well, carefree. But about 200 years ago, the entire region was rocked
by enormous earthquakes, and experts like Gary Patterson say Memphis has something to
worry about. So here we are on Beale Street on a Saturday
night, and, obviously, the place is packed. From what I understand, luckily, Memphis didn’t
exist when the big quakes were happening in 1811 and 1812. GARY PATTERSON (University of Memphis): That’s
right. We didn’t have instruments in the ground, but we know they were really big. They really
happened and they could really happen again. What happened was that the midwest was hit
by not one, but three epic earthquakes, with epicenters somewhere near the town of New
Madrid, Missouri. According to eyewitnesses, parts of the Mississippi
River changed direction. TISH TUTTLE (U.S. Geological Survey): Geysers
of water and sand went shooting into the air. Fissures were forming in the ground. Some
of them were so large that they were afraid they’d be swallowed up by them. PETER STANDRING: In fact, one report claimed
eight Indians were killed by the opening and shutting of the earth. There weren’t any big cities in the region,
and no one knows how many people died, but the tremors were so strong, they were felt
from Mexico to Canada, over a thousand miles away. How is it possible that some of the biggest
quakes in American history would strike in the middle of the continent, where there are
no visible faults, and away from the plate boundaries? GARY PATTERSON: It’s an enigma. It’s, it’s,
it’s a, it’s a puzzle. PETER STANDRING: To help solve the mystery,
geologists are trying to uncover the truth of what happened here in the past. And that’s
why I joined geologist Sam Panno and his team on their little cave adventure, to track down
rocks that bear the imprint of ancient earthquakes. And I expect we’re going to get muddy? SAM PANNO: A little bit. PETER STANDRING: If we want to find the right
rocks, it turns out we need to go underground, and we need to get a little wet. Hey, Sam, I guess that trail of popcorn that
I dropped behind us isn’t going to do us any good at this stage. SAM PANNO: I guess not. PETER STANDRING: Lucky for me, Sam knows his
way around these tunnels, all 14 miles worth. He’s been trekking through midwestern caves
for years, on the hunt for stalagmites, those spikes of rock that grow up from the cave
floors. Since they build up gradually, from minerals
dripping from above, each stalagmite carries a unique geological record, sometimes stretching
back tens of thousands of years. If earthquakes happened here, the stalagmites
will prove it. SAM PANNO: Stalagmites grow layer upon layer. PETER STANDRING: Break a stalagmite in half,
and you can see rings of growth, kind of like tree rings. SAM PANNO: You have the youngest rings on
the outside, the oldest ring on the inside. PETER STANDRING: So a stalagmite like this
one, for example, may have taken tens of thousands of years to grow to that height? SAM PANNO: That’s about right. PETER STANDRING: For years, Sam has been taking
samples of these rocks to hunt for signs of earthquakes hidden in their crystal rings. Back in the comfort of a warm, dry lab, the
collection starts to tell a story. BRUCE FOULKE: That one layer would have been
a split. PETER STANDRING: Bruce Foulke, at the University
of Illinois, studies the rocks Sam gathers. Even the rough shape can reveal past earthquakes. BRUCE FOULKE: You can see that the outermost
layer here is shifted. Instead of growing here, it’s moved down and shifted off to here.
The reason that’s happened is the stalagmite is growing from a point source of water that’s
dripping, dripping, dripping. Then we had earthquake activity, and the position of the
drip moved. And now the new drip started accumulating
and growing a new stalagmite in this position, which is down and off the shoulder of the
old stalagmite. PETER STANDRING: Whenever they spot a shift
like this, the team cuts a paper thin slice of stalagmite. With a powerful microscope,
Bruce can isolate individual crystal layers… BRUCE FOULKE: Wow. PETER STANDRING: …and see exactly where
the earthquake happened. BRUCE FOULKE: That specific line is represented
here on the microscope screen by this dark area of crystal growth. PETER STANDRING: To date the earthquake, they
don’t count the rings like you do with tree rings. Instead, high precision chemical analysis
of the crystals reveals how long ago they formed. When the results for this stalagmite came
back, the team discovered that this major shakeup dates to about 200 years ago, a remnant
of the great quakes of 1811 and 1812. And with other samples they’ve gathered, the
team has uncovered more. In fact, the rocks reveal a pattern of violent
midwestern earthquakes stretching back at least 15,000 years. The 1811, 1812 quakes
weren’t a freak one-time event. And if they happened many times before, then they will
probably happen again. The big question is when. Today, the whole region, called the New Madrid
Seismic Zone, is carefully monitored by seismic sensors. It turns out the ground here is shaking
almost every day. GARY PATTERSON: We have about 200 small earthquakes
per year, 90 percent of those too small to be felt by humans. It’s the most active seismic
zone east of the Rockies. PETER STANDRING: So why is the midwest made
of such shaky ground when there are no visible faults on the surface? According to one theory, it’s because the
region lies over an ancient wound, deep down in the earth’s crust. GARY PATTERSON: Half a billion years ago,
the North American continent was being pulled apart by plate tectonic forces. And it created
a rift. PETER STANDRING: But at some point, the continent
stopped breaking up. GARY PATTERSON: For some reason, that rift
failed. PETER STANDRING: The failed rift created a
weak spot in the crust, which might make the region more vulnerable to quakes, but no one
really understands how. To try to get a better picture of what might
be going on, Beatrice Magnani is probing the earth’s crust beneath the Mississippi River. Chugging along in a tugboat, her team sends
powerful sound waves down through the water, and a mile deep into the earth’s crust. As
the sound waves bounce back, they’re picked up by dozens of small microphones trailed
by 80 yards of cable in the river. The echoes reveal distinct layers of sediment. BEATRICE MAGNANI (University of Memphis):
Reading the sediments is like reading a book. The sediments tell us the story of what happened
with time. PETER STANDRING: What happened was these layers
became deformed and folded by major earthquakes. But as Magnani discovered, these folds were
outside the currently active New Madrid Seismic Zone. BEATRICE MAGNANI: Nobody knew about these
faults. It’s actually a discovery that…it’s even more puzzling than not finding anything. PETER STANDRING: For Magnani, it means that
over the eons, the danger zone in the midwest may jump from one area to another, which makes
it even more difficult to predict future big earthquakes in an area that is underprepared. This city wasn’t even founded until seven
years after the great earthquakes of 1811 and 1812, so it’s hard to imagine what would
happen if something of the same magnitude occurred in this region today. If the 1811 and 1812 quakes are repeated,
they will affect much more than Memphis, but also the entire region stretching to the north,
including St. Louis. GARY PATTERSON: A huge area would be affected,
possibly an area containing 12 million people. There’re a lot of old buildings. PETER STANDRING: Whenever it happens, the
next big midwestern earthquake is guaranteed to be catastrophic, destroying billions of
dollars in property, and affecting millions of lives. Yet, unlike Californians, many people here
remain unaware that their cities and towns stand on potentially very shaky ground. PROFILE: SANG-MOOK LEE
NEIL DeGRASSE TYSON: Scientific research is filled with challenges like will your experiment
work or won’t it? People can invest years of their lives, not knowing if they’ll get
the payoff of a big discovery. In this episode’s profile, we meet a man who
met all the ordinary challenges to become a successful researcher, and then one day,
quite suddenly, was handed a whole new set of overwhelming obstacles that his passion
for science empowered him to overcome. Meet Sang-Mook Lee. Where he’s from, he’s
known as the “Stephen Hawking of South Korea.” SANG-MOOK LEE: “Sang-Mook Lee, professor of
Seoul National University, also known as Stephen Hawking of Korea.” That’s like a fixed quote.
Every time I’m cited, they cite like that. He looks into the universe; I look into the
bottom of the sea. NEIL DeGRASSE TYSON: Sang-Mook is an esteemed
professor at South Korea’s top university, and one of the foremost geophysicists in his
country. He studies underwater volcanoes and tectonic plates deep beneath the ocean. Yet, just three years ago, he was in a near-fatal
car accident that left him paralyzed from the neck down. Many thought he would never
work again. MIKE GURNIS (California Institute of Technology):
He was heavily sedated; he couldn’t move; the machines were keeping his lungs going,
but you could just see a light in his eye and that there was a future out there. NEIL DeGRASSE TYSON: He made an impossible
comeback. He has since emerged as a national hero. KUNWOO LEE (Seoul National University): By
showing his attitude, will become a hope for every handicapped people. NEIL DeGRASSE TYSON: He credits his return
to his passion for science. SANG-MOOK LEE: I just love science. I knew
I had to get back because it was something I really wanted to do. NEIL DeGRASSE TYSON: Sang-Mook’s love for
science began as a child, when he dreamt of exploring the world. SANG-MOOK LEE: That’s when I dreamt about
being a globetrotter and going around the world at very exotic places. NEIL DeGRASSE TYSON: He went after this dream.
Getting a Ph.D. in geophysics from M.I.T., he began a life on the sea. SANG-MOOK LEE: When I returned back to Korea,
I became the marine geophysicist in Korea, and we had the ship. That was when my science
got really, really exciting, because I was the only one in charge of this big ship. You’re
being like pirate. NEIL DeGRASSE TYSON: His research involves
studying the submarine activity of tectonic plates, those massive slabs of rock that make
up Earth’s crust. SANG-MOOK LEE: We use indirect ways to image
what is below the seafloor, because all the records are preserved in the ocean. NEIL DeGRASSE TYSON: Shooting seismic waves
through the ocean floor creates a picture of what lies inside the earth. These pictures
allow him to monitor underwater earthquakes and volcanoes, and learn more about how Earth’s
crust was formed. SANG-MOOK LEE: What I do is I study the past
200-million years of Earth’s history, to understand how Earth has behaved in the past four and
a half billion years. NEIL DeGRASSE TYSON: Sang-Mook hopes that
by studying the tectonic activity in uncharted regions, we might someday be able to forecast
geological disasters, like tsunamis and earthquakes. SANG-MOOK LEE: I looked at the map of the
western Pacific, and I tried to choose targets where nobody has gone before. I think that
is the real essence of science, discovery, like, climbing up the peak of a mountain that
nobody has gone before. NEIL DeGRASSE TYSON: But everything changed
on July 2, 2006, on a field trip to California, with a group of students. SANG-MOOK LEE: It was toward the end of our
trip, and we were working toward Death Valley. I don’t remember anything, that day, nothing
at all. People will tell me, “This is what happened. This is what happened.” “Oh, is that so?” I don’t recall anything.
My van flipped, and I was crushed in the seat. NEIL DeGRASSE TYSON: Sang-Mook’s fourth cervical
vertebrae had been fractured, and he was in a coma. SANG-MOOK LEE: When I was still in coma, I
knew that I was injured. And I said, “Oh, Sang-Mook, you’re in trouble.” And then, I
said, “But Sang-Mook, you have been in difficult situations before, so you can come out of
this trap. Figure out what to do.” NEIL DeGRASSE TYSON: He awoke from his coma
after three days, paralyzed from the neck down. SANG-MOOK LEE: Immediately after the injury,
I worried that I wouldn’t be able to work. NEIL DeGRASSE TYSON: And he worried about
the challenges that South Koreans with disabilities commonly face, challenges like economic hardship
and family problems. Married with three children, Sang-Mook Lee and his family would ultimately
separate, and although financially able to provide for his own care, he knew he would
have to contend with the stigma that so often accompanies disability, especially in South
Korea. DAN SHIM (Massachusetts Institute of Technology):
People with disabilities are not well accepted in this society. And they tend to hide in
a shadow and, you know, they don’t want to expose themselves. Even taxi drivers will
refuse to, to get you on, if you have disability. SANG-MOOK LEE: In Korea, people with my level
of injury would stay in the hospital, or would shun from the society, but I was not embarrassed
to come back to my work and to try to do what I used to do. NEIL DeGRASSE TYSON: Using all the technologies
available, he was out of bed within a month of his accident. SANG-MOOK LEE: Science played a very, very
important part for me to come back after the injury. Because of my interest in science,
I just thought, “I must go back to work.” MIKE GURNIS: Suddenlyóand it was, it seemed
like it was suddenlyónow he was in motion again. He had this chair, and he had all of
the gizmos. And he could literally move the wheelchair around, turn it, and then also
use computer devices, almost immediately, by breathing into a straw. He also could move
his head back and press a button by moving his head. I mean it was extraordinary to see
this happen so quickly. NEIL DeGRASSE TYSON: Just six months later,
Sang-Mook returned to teaching. SANG-MOOK LEE: One day, a reporter noticed
me. This reporter was from one of the major newspapers in Korea. He heard about me, but
when he saw me, it shocked him, and he knew from reporter’s instinct that
this could be a big story. And the next day, on March 5th, this very big newspaper in Korea
ran my story on the front page. NEIL DeGRASSE TYSON: The attention made him
immediately recognizable throughout his country. MIKE GURNIS: As time went on, he then assumed
this greater and greater role to become a spokesperson for disabled people within Korea. NEIL DeGRASSE TYSON: He now hosts his own
radio show, writes a column on disability in South Korea’s biggest newspaper, and he’s
written a popular book about his work in the sciences. WOMAN: I was incredibly moved by your book. SANG-MOOK LEE: I feel very fortunate that
I had an opportunity to reevaluate myself at that moment in my life. I asked myself,
“What can I do to give back? What can I do actively to give back?” NEIL DeGRASSE TYSON: Sang-Mook’s biggest project
is a multimillion dollar undertaking, funded by the South Korean government, and it’s finding
ways to help other handicapped South Koreans get back in the workplace. SANG-MOOK LEE: Why do so many disabled students
only take the civil service exam? We need to lead more of these students to go into
computers and science. NEIL DeGRASSE TYSON: As part of this program,
he’s working to discover and develop technologies for the handicapped, including Korean voice
recognition software and robotic limbs. SANG-MOOK LEE: You and I may run a shop. NEIL DeGRASSE TYSON: In a city where Sang-Mook
often has to bring his own ramp just to get around, there’s still lots of work to do. SANG-MOOK LEE: It is very difficult, you know?
Basically, we have to remodel Seoul. NEIL DeGRASSE TYSON: But this hasn’t stopped
him. His love for science has him globetrotting once again. He recently made his first overseas
trip since his accident, to an international science conference in San Francisco. MIKE GURNIS: That he can come to an international
meeting, fly across the Pacific, interact with his colleagues, present his scientific
work, it does symbolize he is now part of the community of scientists, once again. NEIL DeGRASSE TYSON: In fact, Sang-Mook has
major research trips planned to explore underwater volcanoes in Tonga and mid-ocean ridges in
the Pacific Antarctic. And although he no longer sails the seas himself, Sang-Mook can
still be the captain of his crew. SANG-MOOK LEE: Now that I’m confined to wheelchair,
I cannot go directly to those places. But nowadays with the development of Internet,
satellite communication, I’m able to participate in many of the cruises, without going directly
to sea. I can enjoy science without getting seasick. Many people heard of my story, that I was
severely injured, and they doubted that I would ever come back. But with the new programs
that are opening up, they will see a lot more of me. NEIL DeGRASSE TYSON: Before we leave, we’d
like to hear your perspective on this episode of NOVA scienceNOW. Log on to our Web site
and tell us what you think. You can watch any of these stories again, download additional
audio and video, explore interactives and hear from experts. If you want to get the
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24 thoughts on “NOVA scienceNOW : 53 – Sleep, First Primates, Earthquakes in the Midwest, Profile: Sang-Mook Lee

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