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"Life's
Really Big Questions"
– SHOW 1103
EPISODE
OPEN
ALAN
ALDA Our ancestors spent a couple of million years bashing
rocks like this to make tools. And that may have helped
make us human. You want to cut some?
ALAN
ALDA (Narration) See how our hands set us free -- and
gave us baseball. How an ancient telescope found an
alien world.
ALAN
ALDA And here we were.
DAVID
LATHAM And tonight's the night!
ALAN ALDA (Narration) Meet a baby robot that may grow
up not needing us.
ALAN
ALDA The computer knows more than I do in this case.
ALAN
ALDA (Narration) And learn why Noah's flood may have
been caused by a snowball.
ALAN
ALDA I'm Alan Alda. Join us as Scientific American Frontiers
heads out to explore Life's Really Big Questions.
back
to top
NOAH'S
SNOWBALL
ALAN
ALDA Every now and then on Frontiers we take a look
at some of the really big questions scientists are asking
-- probably the kind of big questions human beings have
been asking ever since we became human. Which is, incidentally,
one of the big questions we'll be tackling today --
just when and how did humans set out on our uniquely
human path? As we'll see later, Tujo here may be able
to help us out with that particular big question. The
thing is that big questions don't have easy answers
-- that's what makes them big. So we may not always
come up with answers to our questions. But asking them
can still be a lot of fun.
ALAN
ALDA (Narration) Of everything that's happened since
the world began, one event was more dramatic than any
other -- and perhaps more significant. Astonishingly,
we didn't even know about it until a year or two ago,
when geologists Paul Hoffman and Dan Schrag came up
with the extraordinary idea that the earth was once
frozen solid, like a snowball. These rocks, on the New
England coast, were formed when the snowball began melting
600 million years ago. In what was then the ocean floor,
a stone fell from the melting ice and plopped gently
into the mud.
ALAN
ALDA Here's a moment, many millions of years ago, where
that ice started to melt just enough for that rock to
fall out of the ice through the ocean and down into
that sediment. And we're looking at a specific moment
in time there.
DAN
SCHRAG That moment, you can put your finger on it and
say, this is the moment of the biggest climate change
in Earth's history, where it flipped from being incredibly
cold to incredibly warm, and we can now tell the story
of that.
ALAN ALDA (Narration) It's a story that's breathtaking
enough by itself. But it may also unlock the answer
to a really big question: how did life become interesting
enough eventually to produce… us. But let's start with
the rocks. What we're walking on may be near Boston
now, but once -- 600 million years ago -- it was in
what later became equatorial Africa.
ALAN
ALDA There were glaciers all over Africa at this time,
is that what you're saying?
PAUL
HOFFMAN That's right. At 600 million years ago, every
continent in the world was covered by ice.
ALAN
ALDA (Narration) And according to my companions' startling
hypothesis, it wasn't just the continents that were
ice bound.
DAN
SCHRAG We see here sea ice that was formed in the last
few weeks. But 600 million years ago, the sea ice was
a mile thick.
ALAN
ALDA A mile thick, the oceans were…
DAN
SCHRAG The oceans were frozen over.
ALAN
ALDA And so the whole earth was in fact this giant snowball.
DAN SCHRAG That's why we call it a snowball.
ALAN
ALDA It sounds more like an iceball, I mean it was really
impenetrable.
DAN SCHRAG It's extraordinary. The idea that this happened
makes you rethink everything that you think you know
-- about life on this planet, about the chemistry of
the earth, about the geology of the earth.
ALAN
ALDA (Narration) Here's what Hoffman and Schrag think
happened. For reasons they don't fully understand, 600
million years or so ago the earth cooled by a few degrees
and the polar ice caps began expanding slowly toward
the equator. As more and more of the earth's surface
became covered with the highly reflective ice, more
and more of the sunlight falling on the earth was radiated
away into space.
PAUL HOFFMAN When you get to about half the earth's
surface covered, that is the ice line's down to about
30 degrees north and south of the equator, then the
effect is unstoppable and the whole thing just freezes
over instantly, all the way to the equator.
ALAN
ALDA Instantly, meaning… how quickly does it go?
DAN SCHRAG Probably in a few years. And once you have
the whole planet white, once the whole planet's surface
is white from the snow and ice, the temperature plummets.
It goes down to about minus 50 degrees C.
ALAN
ALDA (Narration) And there the earth might have remained
forever --- a brilliant white cloudless snowball floating
in space. What saved it were its volcanoes, poking through
the ice and spewing into the atmosphere the gas that
today we fear may be leading to global warming -- carbon
dioxide. Eventually carbon dioxide built up to levels
where the Greenhouse Effect kicked in with a vengeance.
Temperatures started to rise, the equatorial ice began
to retreat -- and the snowball melted as suddenly as
it was formed.
DAN
SCHRAG When the snowball ended and you started to melt
the ice at the equator, you could say literally all
hell broke loose, where in a hundred years you go from
a completely frozen planet to the warmest state the
earth's ever been in.
ALAN
ALDA (Narration) This cataclysmic climate change must
have been devastating for life on earth -- or so you'd
think. But life today is very different from life 600
million years ago -- when it was quite literally still
stuck in the mud -- boiling mud.
ALAN
ALDA Is this whole park on a crater, a volcanic crater?
SUE
BARNES That's right, that's what Yellowstone is, the
remnants of a massive volcano that occurred on the order
of 800,000 years ago. Blew ash all over the western
United States and this is what is left of it. It is
still pretty active.
ALAN
ALDA Pretty...This is as active as it is ever going
to get now?
SUE
BARNES Ever, no.
ALAN
ALDA It is going to blow again, you are telling me.
SUE
BARNES We are very...there is a very thin crust area.
It could well..
ALAN
ALDA Are we standing on one of the places that ...
SUE
BARNES It is going to come up here first.
ALAN
ALDA It's bubbling already.
SUE BARNES That's right.
ALAN
ALDA (Narration) Whenever they visit here, biologists
Sue Barnes and Norman Pace first measure the water temperatures
-- which seem way too high for the sort of life that
occupies most of the planet today.
NORMAN
PACE So this is going to be all water temps now, Sue.
SUE
BARNES O.K. That's fine.
NORMAN
PACE O.K. Read them off.
ALAN
ALDA 182, 180
SUE
BARNES Whoa.
ALAN
ALDA I'm sorry.
NORMAN PACE No, it's o.k.
SUE
BARNES It's not fatal.
ALAN ALDA Have you lost many microbiologists?
SUE BARNES Nope.
ALAN
ALDA I saw a bleached bone up there.
ALAN ALDA (Narration) But in fact there is life here.
Even where it's boiling, the mud is teeming with microscopic
creatures.
ALAN
ALDA All my life I have been taught that if you boil
the water you will kill anything nasty in it. And if
you boil the medical instruments, you will make them
sterile.
NORMAN
PACE That is certainly true for the sorts of organisms
that would infect us. They would not survive the boiling.
But if you evolved, if you were capable of, if you are
in fat city if you are in such a hot environment, then
it doesn't matter.
ALAN
ALDA (Narration) We've brought along a microscope, to
take a look at these heat-loving creatures.
SUE
BARNES Should be in focus.
ALAN
ALDA (Narration) I'm looking at the sort of microbes
Sue and Norm believe were once -- and for a very, very
long time -- the only life on earth.
ALAN
ALDA That was -- that's like looking through a time
machine in a way...
NORMAN
PACE In a very real way...
ALAN
ALDA To the earliest days.
NORMAN
PACE In a very real way. I think that, that these organisms,
the general properties of these organisms will be not
at all too dissimilar from the nature of the earliest
organisms.
ALAN
ALDA (Narration) Even after two billion years of evolution,
this is all life had come up with. At least it was well
equipped to survive the snowball, nursed through the
deep freeze by the heat of the same volcanoes that eventually
re-warmed the earth. But life not only survived the
snowball. It was about to be transformed. To see how,
we've come to southwestern China. Our journey begins
with a train ride on a rainy summer morning. On board
the train is biologist Andy Knoll.
ANDY
KNOLL We've all heard of the Big Bang through which
the universe is thought to have begun. But in biology,
there's another kind of big bang--a big bang of animal
evolution. Life began at least three and a half billion
years ago, but it wasn't until 580 to 570 million years
ago that we see any kind of animal life--and then, in
just a few million years, we have a tremendous diversification
of different types of large and complicated animals.
And here in China, we see one of the best available
records of that biological big bang.
ALAN
ALDA (Narration) It's in the Chun Jiang Hills of Yunan
that you can see spectacular fossils of those first
animals, in rocks that formed out of mud on the bottom
of an ancient ocean, 550 million years ago. In rocks
just a little older than these, all fossils are still
microscopic -- so this place marks the very beginning
of animal life. There's been an excavation here for
almost five years, and today Andy is meeting the man
behind it, paleontologist Chen Jun Yuan.
ANDY
KNOLL It's in there that the event beds that really
captured the fauna are found.
CHEN
JUN YUAN Yeah, yeah.
ALAN
ALDA (Narration) The real fossil hunting here takes
place across the road, where 30 local women split the
newly excavated rocks into thin slices. They get paid
about 50 cents per fossil found -- plus a bonus for
unusual discoveries. The rocks are loaded with fossils.
ALAN
ALDA (Narration) While the fossils come pouring in,
Professor Chen tries to figure out what they were. Andy
Knoll ...two valves, and then the animal inside is a
little bit shrimp-like.
CHEN
JUN YUAN Yes.
ALAN ALDA (Narration) This seems to have been a kind
of combined clam and shrimp.
ANDY
KNOLL It has almost like a fin on it, which would help
it to move through the water.
CHEN
JUN YUAN Yes. Andy Knoll Interesting. How about this,
these look like big pincers.
ALAN
ALDA (Narration) And this fossil has the familiar look
of a lobster claw. Chen's never found a whole one, but
he's got enough parts to know these animals could get
huge.
CHEN
JUN YUAN The largest one can be two meters long. Andy
Knoll Two meters long, that's...
CHEN
JUN YUAN Very large, a large mouth. Andy Knoll And so
this could eat everything else in the whole Chun Jiang
fauna.
CHEN
JUN YUAN Right.
ALAN
ALDA (Narration) Many of the fossils don't look like
anything alive today. But for the first time, life had
broken through the constraints imposed by being simple
single-celled creatures, and had begun an explosive
exploration of the possibilities of complexity. Animals
had arrived. And that brings us right back to our snowball.
PAUL HOFFMAN The question ultimately is, were animals
inevitable? Would biology have come up with animals
in any case, or did you have to hit biology over the
head with a hammer?
DAN
SCHRAG Or hit them with a snowball. ALAN ALDA So it
sounds like you feel you had to hit it over the head
with a hammer.
PAUL
HOFFMAN Yeah, because of the coincidence in timing.
It's hard to ignore the fact that you had this explosion
of multicellular animal life in the immediate aftermath.
DAN
SCHRAG For two billion years you had algae and bacteria
living and nothing happened. And then all of a sudden,
after you've had these repeated glaciations, that's
when multicellular life occurred. It's possible that
it's a coincidence, but I think it's unlikely.
ALAN
ALDA Yeah, it's such a giant event…
DAN
SCHRAG Yeah, it's amazing.
ALAN
ALDA It's such a clear marker in history.
DAN
SCHRAG Exactly. I mean, in some ways it's like Noah's
Flood, a catastrophe and then a redemption that actually
ends in a much more interesting world than you had before.
ALAN ALDA (Narration) It's a captivating idea: that
volcanoes saved both our planet and our ancestors from
an icy coffin, in a period of cataclysmic climate change
that kick-started animal evolution -- and that eventually
led to us. While Paul Hoffman and Dan Schrag are very
aware that the snowball earth hypothesis is just that,
a hypothesis -- they are still savoring its invention.
ALAN
ALDA When all this came together for you, was it a gradual
process or was it a volcanic explosion?
PAUL
HOFFMAN Well in my case it was like a flash. And all
of a sudden my world was transformed. Because not only
did I suddenly get this clue but I just knew in my bones
almost from the instant not only that it was right but
also that it was a big thing, a big deal.
DAN
SCHRAG We tend to… Both Paul and I are night owls and
we tend to talk late at night about science. And at
about one or two in the morning we had a conversation
and it was sort of an epiphany for both of us. And as
a result for the next two months we were both scurrying
back and forth, new ideas flying, and that exciting
discovery, being able to go out into the field and know
that you've forever changed the way people think about
this, that moment of discovery was amazingly exciting.
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HANDMADE
HUMANS
ALAN
ALDA Billions of years of evolution has produced probably
billions of different living things. But of those billions,
only one -- so far as we know -- wonders about how and
even why it's here. Which poses perhaps the biggest
of life's big questions. What happened some four or
five million years ago that set us off on our unique
journey to becoming Homo sapiens? We know it happened
in Africa, when a species of ape left the trees of the
forest behind and strode away on two legs, freeing its
hands to become… well, that's what our next story is
going to explore.
RESEARCHER
Make a fist. Point at something.
ALAN
ALDA (Narration) I'm returning to the stone age -- equipped
with a cyberglove, able to measure every subtle movement
of my fingers and hand. It's a great mix: the very latest
in high tech being used to study the oldest tech of
all -- tools made of stone.
RESEARCHER
Close your fist.
ALAN
ALDA Ah, there, I got a nice piece there.
STEVE
SHAKELY I think we have natural here.
ALAN
ALDA Now I have two. Here, you want to cut some? I'll
go halves with you on that antelope. Well, how did I
do with this? Mary Marzke I think we're quite impressed
with how you did with that. Very effective. Removed
a lot of flakes.
ALAN
ALDA So that must mean it must be innate, right?
ALAN
ALDA (Narration) That's the idea we're exploring in
this story -- that our hands were designed for making
stone tools -- that they were in fact designed by making
stone tools.
STEVEN
SHAKLEY You've got quite a cutting edge here, so you'd
be quite competitive. So you can move up 100,000 years.
ALAN
ALDA (Narration) Of course, the hands of our ancestors
got a great start. This is Tujo the orang-utan, one
of the stars of the Phoenix Zoo. Orangs and humans last
shared a common ancestor about 12 million years ago.
While we've both been evolving ever since, Tujo's hands
give us a glimpse of what ours may have once been --
extremely dexterous, but shaped by a life in the trees.
MARY
MARZKE You notice that he's carrying it in his foot.
ALAN
ALDA Yeah.
MARY
MARZKE When they're moving around, they have two hands
that they're moving on the branches with. And the only
way to keep the fruit with them is to carry it in the
foot. And the feet act very much in coordination with
the hands in manipulating foods.
ALAN
ALDA (Narration) Tujo uses his feet not just to carry
the grapefruit but to help eat it too -- and needs at
least both of his hands to help resist the pull of his
teeth.
MARY
MARZKE Possibly we would do that with a big piece of
fruit, but as it gets smaller we would get a good purchase
on it with our thumb and fingers which adapt to the
shape of the grapefruit.
ALAN
ALDA (Narration) To Mary Marzke this is an important
clue as to what makes our hands different -- and far
more capable. But before our hands could change they
had to be free. And that meant standing on our own two
feet.
ALAN
ALDA Is that Lucy there?
WILLIAM
KIMBEL This is Lucy. This actually is a copy of her
bones.
ALAN
ALDA (Narration) Our most famous ancestor, Lucy lived
about 3.2 million years ago in what is now Ethiopia.
ALAN
ALDA How do you know she was an adult?
WILLIAM
KIMBEL Well, we have her lower jaw. And we can see that
her last molar tooth, the so-called wisdom tooth, is
erupted and was being used for chewing. (And we can
actually see that) because the tips of the little cusps
on top of the teeth are polished and worn, (meaning
that she was using them to chew.) That's full adulthood.
Three and a half feet tall, however, which is you know,
when down on the ground is not much bigger that a good
sized umbrella you know when you put its tip on the
ground. So she's very tiny. Her brain -- although we
don't have too much of her skull, unfortunately -- what
we do have suggests a brain size not much bigger than
that of a chimpanzee. And that really drives home one
of the most important points about Lucy. And that is
the stark contrast between her anatomy beneath the neck,
which is fully consistent with an upright two-legged
walking; and the anatomy above the neck with a very
primitive ape-like jaw and teeth and a very tiny brain.
ALAN
ALDA (Narration) One of the below-the-neck features
suggesting Lucy walked upright is her pelvis -- short
and wide when compared to the pelvis of a chimp. Then
there are the leg-bones themselves.
WILLIAM
KIMBEL You can see here's the hip and here's the knee.
And there's a very pronounced angle as the thighbone
runs from the hip joint to the knee. With the knees
being much closer together.
ALAN ALDA Yeah, I can see that over here too.
WILLIAM
KIMBEL Very obvious. Very obvious in a human. And in
a chimpanzee, when it stands upright, that's not the
case. The thighbone is more or less perpendicular to
the ground, in contrast to what we see in Lucy and modern
humans.
ALAN ALDA (Narration) This combination of a tall pelvis
and upright thighs give chimps their characteristic
waddle when they walk on two legs -- not an efficient
way of getting around -- especially when you're in a
hurry. But Lucy was probably quick on two legs, and
she had bipedalism's most useful spin-off -- genuine
hands rather than modified feet.
ALAN
ALDA Is this Lucy's hand or one of her relatives?
MARY MARZKE This is a composite set of hand bones from
Lucy's relatives. Beautifully preserved. Very nice joint
surfaces. And some of the interesting things are at
the base of the index finger where there are three joint
surfaces, and these surfaces are oriented in the way
that they are in modern humans. And they are all different
from the way that they are oriented in chimpanzees.
And the different orientation would have allowed a little
bit of rotation of the index finger…
ALAN
ALDA Rotation meaning what?
MARY
MARZKE Rotation toward the thumb. And when you rotate
the index finger toward the thumb, this helps you to
grasp.
ALAN
ALDA (Narration) Lucy's ability to pick up and firmly
grasp an object like a round stone opened up a whole
new way of earning a living. Chimpanzees throw stones
-- but underhand and not very accurately. Lucy's ability
to hurl a rock hard and on target brought her into a
different league.
ALAN
ALDA Would Lucy have been able to pitch?
MARY
MARZKE She could have. She had the anatomy to do it.
And if she had practiced she would have been able to
pitch. She had a hand that could have grasped the ball,
and controlled it. And she had a pelvis that allowed
the balance of the trunk on the hind limbs. So she could
have used her trunk as leverage in pitching. As we watch
these pitchers, they're rotating their trunk and then
they're putting on the brake with their gluteus maximus
muscle so that their arm accelerates in a whip-like
way. And she had both of these features both in the
hip region and in the hand. So it takes a lot of practice,
but she could have done it.
ALAN ALDA (Narration) Of course, Lucy's strikes weren't
on batters but small game -- and could have significantly
increased her food supply. We're back in the lab again,
where Mary has assembled a team of experts to delve
more deeply into the link between anatomy and the technological
breakthroughs that set our ancestors apart from everything
that had lived before.
RONALD
LINSCHEID Ouch!
ALAN
ALDA (Narration) Dr Ronald Linscheid is a retired hand
surgeon. Nick Toth is an archeologist. The needles in
Nick's arm and hand are implanting thin wire electrodes
into his muscles to measure how vigorously they contract.
RONALD
LINSCHEID You're going to feel a little stick right
about there. May have felt that hit the bone a little
bit.
ALAN
ALDA (Narration) Nick will also be wearing the cyberglove
I was modeling earlier -- and you'll understand now
why my participation in the experiment ended right there.
MARY
MARZKE Alright Nick, imagine there's an animal there,
and that's your food for the night.
ALAN
ALDA (Narration) Mary's purpose in organizing this little
party is to closely monitor the hand and its muscles
when Nick, then his wife, Kathy Schick, start behaving
like stone-agers. Our ancestors from the time of Lucy
-- 3.2 million years ago -- may have been hot on the
mound… But they would have had problems at the plate.
Here's a chimpanzee letting off steam with a stick.
He's swinging it with great determination, but his grip
is quite different from that used by a baseball batter.
Our old friend Tujo the orang-utan uses the same grasp
as the chimp, with all four fingers curled into his
palm. Neither modern orangs nor chimps -- or even, it
turns out, Lucy -- can do what we can do: rotate our
little finger across the palm to touch the thumb.
MARY
MARZKE The advantage of having this rotation can be
seen when you hold something cylindrical, like this
bone, where you grasp things in a trough, across the
palm with the little finger and the thumb strongly opposed.
And this allows you to bring the tool down in line with
your arm.
ALAN
ALDA That's interesting. I was taught in tennis to squeeze
these last two fingers as I hit the ball. And that gives
control.
MARY
MARZKE Yes.
ALAN
ALDA And that's what they were able to do when they
shifted over to this kind of a finger.
MARY
MARZKE Yes.
ALAN
ALDA (Narration) It was a shift that didn't take place
for a few hundred thousand years after Lucy's time --
but when it did, our ancestors would certainly have
made the most of it. After stunning, say an antelope
with a well-aimed stone, the tennis racquet grip would
have made finishing it off much easier. Of course, not
everything was easy to kill.
ALAN
ALDA So what did it take, about a million years for
people to find out you couldn't kill a pillow?
ALAN
ALDA (Narration) But look at this. As Steve Shakely
takes his turn with the glove and the electrodes while
making a stone tool, you can see he's relying on the
flexibility of his hand to manipulate and grip the stone
he's hitting.
ALAN
ALDA There's so much attention paid to the opposable
thumb. But the opposable pinky turns out to be really
valuable. I mean, if I hit this stone without that little
finger giving me pressure, this stone would just come
right out of my hand, right?
MARY
MARZKE Yes.
ALAN ALDA I can really manipulate it and keep it right
where I need it with strength.
ALAN
ALDA (Narration) So while Lucy could have gripped the
hammer stone like a baseball, only her descendents could
have cradled the stone being struck firmly enough to
have fashioned it into something useful. Mary Marzke
plans to use the data she's getting from her volunteer
Stone-agers to help her interpret the fossil bones that
are all that remain of our ancestors. Kathy Schick meanwhile
has re-discovered the one inescapable consequence of
making stone tools.
ALAN
ALDA So what have you left yourself with here?
KATHY
SCHICK Tourniquet! You don't want to see this.
ALAN
ALDA Oh God! You know this is heroic what you're doing
for science. In all the years we've been doing this
show I've never seen people bleed for science like that.
KATHY
SCHICK Only a flesh wound!
ALAN
ALDA (Narration) From the time our still non-human ancestors
started making stone tools two and a half million years
ago, until just a few thousand years ago, this is how
we fashioned the tools and weapons we used gradually
to dominate our planet. With grips we use today to hold
a bat and ball, our hands helped make us human.
ALAN
ALDA I get the impression talking to both of you that
we can do amazing things with our hands now because
of what these people did a couple of million years ago
with stones. We can work the keys of a computer. But
I also get the impression that the very invention of
a computer, the way we use our minds to come up with
a computer, is in a way an outgrowth of this stone work.
STEVE
SHAKELY Very much so.
ALAN
ALDA Trace that for me a little bit. You may not be
able to document every step along the way, but what's
your thinking on that?
STEVE
SHAKELY Well, I think a lot of it has to do with, we
as human's ability -- and I think that really separates
us much from the animal world -- this ability to look
into the future. To build something today that will
make our lives easier tomorrow. Now some might argue
that computers don't necessarily do that, they make
our lives more complicated. But I think that in general
that's why computers were invented, to make our lives
easier in the future, to get through the day. And stone
tools were no different. And somebody 2.5 million years
ago must have discovered and thought and invented this
piece, this flake, to make his or her life easier in
the future.
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ROBOT
INDEPENDENCE
ALAN
ALDA (Narration) Evolution may have created billions
of different living things. But it hasn't stopped there.
Thanks to our invention of the computer, evolution is
now producing a whole new generation of creatures.
KARL
SIMS Evolution by itself has led to the creation of
incredible complexity. Ourselves, all the organisms
in the world. This process happened on its own. At least
in my opinion. There was nobody that assembled all of
these wonderful things in the world. On computers, we
can simulate the same process and we can get these very
complicated, very interesting things without having
to understand them and assemble them.
ALAN
ALDA (Narration) Karl Sims was one of the first researchers
in what is now a burgeoning field --- artificial life.
He started by giving his computer the instructions for
a set of basic parts.
KARL SIMS The bodies of these creatures are fairly simple.
They're just made of some number of blocks. The blocks
are connected by joints which can bend or twist. The
creatures also have a nervous system. They have sensors
which can sense the angle of the joints or sense contact.
And the nervous system processes the signals from the
sensors and tells the muscles when to move, which generates
some kind of behavior. I've given it the capabilities
to include all these elements but the computer actually
decides how they're assembled and used in specific creatures.
ALAN
ALDA (Narration) Numbers chosen randomly by the computer
-- a synthetic genetic code -- described how the first
simple creature would look, and how its nervous system
would be wired. Then it was put into a simulated lake
and told to swim. It twitched but didn't get anywhere,
so now the computer went to work. Using the original
numbers as its base, the computer made a few random
changes -- the equivalent of mutations. It did this
again and again, creating a new generation of 300 different
offspring. Then all the offspring got a swimming test,
with the best swimmers selected as the basis for the
next generation. KARL SIMS When the computer makes mutations
in the genes of these creatures, it has no idea what
these mutations are going to do. Sometimes the mutations
might knock out pieces of the nervous system and perhaps
cause the muscles not, not to move any more. But other
mutations might actually improve the motion.
ALAN
ALDA (Narration) So from the original creature, increasingly
better swimmers evolved over generations, all without
any human intervention. In the end, this was the best
swimmer of all. But when Karl Sims put it on simulated
land... it was like a fish out of water. So over subsequent
generations, the mutation and selection process had
a new goal -- to walk. After 15 generations, this was
the champion. Other computer runs have produced even
better walkers
KARL SIMS Sometimes these evolving creatures would think
of solutions to their goal which were completely different
than I expected. In this one example, the creatures
got taller and taller and taller, and would simply fall
over. Instead of figuring out some clever way of walking,
they would fall to generate horizontal velocity. What
I was telling them to do was to just move, and falling
was a perfectly good solution as far as they were concerned.
So this creature specialized in falling for as long
as it possibly could, including doing a complete somersault.
ALAN
ALDA (Narration) Karl Sims' creatures may have evolved
some very clever tricks, but they are confined to the
virtual world of the computer screen.
ALAN
ALDA All right. What do I do, take a piece and put it
next to this?
ALAN
ALDA (Narration) But here in Jordan Pollack's lab at
Brandeis University, artificially evolved creatures
have already taken the first steps into the real world.
ALAN
ALDA You know, you should have had a five-year old come
and do this. What am I making here?
PABLO
FUNES We call it a lamp. We don't really know what it
is. It's a structure that the computer evolved or designed
through evolution.
ALAN
ALDA (Narration) The Brandeis computer is told the basic
facts about Lego bricks -- their weight, how firmly
they stick together and so on. Then through hundreds
of generations the computer uses its virtual Legos to
evolve structures selected for how well they perform
a certain task -- in this case, to hold a 20 gram weight
as high and as far to the left as possible. This is
the computer's best current solution. A human -- in
this case me -- gets involved only to build it. This
design was evolved to reach out as far as possible without
breaking. And this crane was evolved in the computer
to lift a 100 gram weight. The point of actually building
the structures is to see how well a design evolved in
the virtual world -- where everything is perfect --
holds up when it meets the real world, where almost
nothing is perfect.
JORDAN
POLLACK Put it down gently sir.
PABLO
FUNES Oh, it broke!
ALAN
ALDA Ahh, was that me or was that the computer?
PABLO
FUNES I think that was…
JORDAN
POLLACK I think that was a gap in the table.
PABLO
FUNES I think that the books moved. ALAN ALDA The book
moved?
PABLO FUNES Yeah, I think that the books slipped.
ALAN
ALDA These books?
PABLO FUNES Yeah.
ALAN ALDA Now there's an example of the real world,
right? That thing worked in the computer. Had you ever
put that catalogue on top of it?
JORDAN
POLLACK No.
PABLO
FUNES Yeah.
JORDAN
POLLACK Oh, yeah, actually, before…
PABLO
FUNES Yeah, we have tried it, yeah.
ALAN
ALDA OK, well, there's another example of the real world.
JORDAN
POLLACK That's right.
ALAN
ALDA Sometimes the real world works one way and sometimes
it works the other way.
JORDAN POLLACK Well, why don't we see if we have more
success standing up today's new structure. Betsy and
Greg have finished it, it's never been tested before.
PABLO
FUNES The other ones had been tested before.
ALAN
ALDA Lot of help that was.
ALAN ALDA (Narration) Now it might seem odd in a show
about life's really big questions to be worrying about
whether a computer-designed Lego lamp is going to stand
up. But Jordan and Pablo see this as the first step
toward something far more ambitious: machines that are
not only designed without humans but are built without
humans. In other words, robots that don't need us at
all.
JORDAN
POLLACK So there it is. It stands.
ALAN ALDA (Narration) But first things first.
ALAN
ALDA It's holding its own weight.
JORDAN
POLLACK It's holding its own weight. And now the question
is, sir, you have a real way with robots…
ALAN
ALDA I have a touch for this.
PABLO FUNES Oh no, not again.
JORDAN
POLLACK So put it between the last two knobs.
ALAN
ALDA (Narration) OK, drum roll please.
ALAN ALDA I'm not going to jerk it, I'm just going to
let it go… Look at that!
ALAN
ALDA (Narration) Mission accomplished. Now about those
robots that can do without us. This artificially evolved
creature is one of several the Brandeis computer has
come up with that are very similar to the ones Karl
Sims' computer created. Except that these creatures
-- with only minimal human help --are already making
the leap into reality
HOD
LIPSON The idea is that not only do we want the robots
to be autonomous in terms of behavior and in terms of
power but we also want them to be autonomous in terms
of their own design and manufacture.
ALAN ALDA (Narration) Hod Lipson has written a program
that allows the computer's design to be directly printed
out in plastic. We've speeded up the time it takes;
but the remarkable fact is that between telling the
computer what the robot should do and actually taking
the robot out of its miniature factory, no human was
involved. There are still a few tricky steps that haven't
yet been automated -- like plugging a motor into… well,
at this point I'm not quite sure what.
ALAN
ALDA The computer came up with this loose hanging down
piece in the evolution of this thing. What was it told
to do, what was it told to make?
HOD LIPSON The only thing the computer was told to do
was to make something that moves. And we will see, this
flappy thing is very important for its motion.
ALAN
ALDA OK, this is great. You know, if you just… I come
up to this table and I look at this and you say the
computer invented this great thing and it moves and
it uses this to move, I'm thinking, I don't think so.
The computer knows more than I do in this case. I can't
wait to see this move around the table. HOD LIPSON That's
the nice thing -- you get creative surprising sometimes
solutions.
ALAN
ALDA Yeah. There, oh look at that. There's something
especially weird and interesting about the fact that
the computer thought it up and then it told another
computer to make it. And then you just had to help it
a little bit….
JORDAN POLLACK Plug in the motors…
ALAN
ALDA (Narration) It's possible of course to see these
awkward machines as the innocent forerunners of a sinister
robot race that evolves beyond our control -- But Jordan
Pollack sees them rather as prototypes for cheap, disposable
robots for everyday use.
JORDAN POLLACK You might (have a meta-robot in your
home and you) say, gee, I want something to clean the
front gutter of my house and you generate a robot and
out it comes and you throw it up onto the roof and it
cleans the gutter of your home, and when it's done you
throw it in the recycling bin.
ALAN
ALDA Oh I have this robot-making machine…
JORDAN
POLLACK A robot-making machine…
ALAN
ALDA Depending on what I need that week.
JORDAN POLLACK Exactly.
ALAN
ALDA (Narration) But as our little robot gets recycled
in the laboratory toaster, it's hard not to wonder if
one day robots that can evolve and manufacture themselves
will find humans unnecessary.
HOD LIPSON These things might completely do without
humans and surpass maybe human engineering capability
and reach something that we can't think of today.
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ALIEN
WORLDS
ALAN
ALDA (Narration) The top of a modest mountain in Massachusetts
may seem an unlikely place to be asking our next big
question: Are we alone in the universe? The telescope
here is almost 70 years old -- and looks it.
ROBERT
Stefanik I can operate the telescope from here…
ALAN
ALDA (Narration) With only a 61-inch mirror, it's puny
by the standards of today's telescopes, located on far
more exotic mountaintops. But it's playing a key role
in searching for alien worlds.
DAVID
LATHAM Come up and take a look at the instrument.
ALAN
ALDA It seems hard to believe that with a relatively
small telescope you can find something so tiny as a
planet.
DAVID
LATHAM Well, we don't find the planet. We only see the
motion that the planet makes on its parent star. In
fact we have a model over here that might help you see
how that works a little better. Here we have our model
of an extra-solar planet. There's a star like the sun,
and then out there swinging around in its orbit is a
planet. Of course planets are much fainter than their
parent stars because they only shine by reflected light.
So it's almost impossible to take a picture of a planet.
Instead we look for the motions of the parent star.
The star is much more massive than the planet so its
motion is much smaller. The planet swings in a wide
orbit and the star swings in a small orbit in response
to the pull of the planet.
ALAN
ALDA Now when you're looking with the telescope, are
you seeing the star move from side to side the way it
appears to me or are you looking at something that goes
away from you and toward you?
DAVID
LATHAM Well, right now it's going away from you and
that's the motion that we're measuring, back and forth
along the line of sight.
ALAN
ALDA (Narration) My hosts point the telescope at a favorite
star.
ALAN
ALDA And what is it you like about this?
DAVID
LATHAM Well I like it because it looks a lot like the
sun. ALAN ALDA What, has it gone behind a cloud now?
DAVID LATHAM Yeah, the star has gone behind a cloud
now.
ALAN
ALDA (Narration) The clouds part long enough for the
star's spectrum to be recorded. And it's these lines
that reveal the star's wobble back and forth.
ROBERT
As the star moves, these lines will shift their position,
depending on what their velocity is.
ALAN
ALDA (Narration) The telescope here is old but it's
cheap -- and that's why it's useful. With it, David
and Robert can sift through hundreds of stars, looking
for just the ones that wobble -- and so are candidates
for those much more powerful telescopes on much more
imposing mountains. Over 13,000 feet up at the top of
Mauna Kea in Hawaii, for instance, is the Keck telescope.
The mirror here is almost 400 inches across. Its ability
to collect far more light means it can see far more
details in the wobbles of stars -- and in the last few
years, the Keck and other huge telescopes have produced
a cornucopia of likely planets -- over 30 in all. Almost
all these other possible worlds are huge and orbiting
much too close to their parent stars to support anything
like life as we know it. The most dramatic discovery
made by analyzing stellar wobbles has been of three
planets orbiting a star in the constellation Andromeda.
But looking for wobbles has its limitations -- at best
it says only that something is tugging on a star.
DAVID
LATHAM But there's another way that you might deduce
that there's a planet in an orbit around a star, and
that's if it happens to go between the observer and
the star. You'll see the light of the star blocked a
little bit.
ALAN
ALDA Right now that planet is not passing across the
plane that the camera's looking, I don't think. It wouldn't
see anything.
DAVID
LATHAM Yep. Too bad. So you have to look at a lot of
stars to see the ones that are lined up just right to
see a transit.
ALAN
ALDA (Narration) And as it turns out, only days before
my the patience of the Harvard team had paid off with
the first ever observation of a planet passing in front
of another star.
ALAN
ALDA Oh, there it is. That's the one, huh?
ROBERT
That's it.
DAVID
LATHAM This is a star that's been in our catalogs because
we've been observing it for seven years. So in August
we gave this star to one of the graduate students at
Harvard and suggested he go look for a transit. And
we told him when to look because of course we know the
orbit so we know when the planet is going in front of
the star, if it goes in front. We had no idea it would
go in front. It might go above it or below it and we
might never see anything. But he's a graduate student,
you know, he has time to do things like that, and damned
if he didn't find it, in September, on the 8th of September,
the 15th of September. A very exciting way to begin
a PhD research program for Mr Charbonneau I can tell
you!
ALAN
ALDA (Narration) From an observatory in Colorado, the
graduate student measured the star's slight dimming
exactly when David Latham had predicted it. The amount
of light blocked gave the diameter of the planet --
the first time this has ever been possible. The planet
turns out to be a little bigger than Jupiter and far
lighter than the Earth -- still an unlikely spot for
life, but unquestionably a planet.
ALAN ALDA This is big stuff, isn't it? I mean…
DAVID
LATHAM This is very exciting. ROBERT Yeah, this is very
exciting.
DAVID
LATHAM Something this exciting only comes along once
or twice in your career. And you caught it!
ALAN
ALDA Here we were.
DAVID
LATHAM And tonight's the night!
ALAN
ALDA And not only that, the clouds parted for us, that's
the great thing. What's drawing you on like this? What
personally is making you look for those planets?
DAVID LATHAM It's on of the big questions. Is there
life elsewhere out there? And if there's life, does
it live on a planet? And are there planets where they
might live? And we have an opportunity in this age to
make a contribution to the answers to those questions.
ALAN
ALDA (Narration) Meanwhile, the contribution of this
elderly little telescope doesn't stop with simply screening
stars for wobbles.
ALAN
ALDA This is your box here?
PAUL
HOROWITZ This is the apparatus that we built at the
Harvard Physics Labs, and you can see it's a sort of
parasite, it's screwed on to the side of the spectrograph
which as you know is looking for planets around other
stars. And we're also looking for planets, but in a
slightly different way. We take about a third of their
light and we look instead for a different kind of signal.
We look for a sudden flash of light from an alien civilization's
laser, sent in our direction to establish contact with
us, civilization to civilization.
ALAN
ALDA (Narration) You heard right: Paul Horowitz is looking
for laser beams, sent our way by aliens who've detected
our planet and are looking to open a dialogue. And if
that isn't amazing enough, he sees what could be a laser
flash every couple of nights or so.
PAUL HOROWITZ We've spent extra time observing many
of these objects because you know, it's kind of fun,
you see a flash in the data in the morning and you'd
have to have rocks in your head to say, well, on to
the next object.
ALAN
ALDA It sounds like it would be a semi-eureka to get
a second flash from an object.
PAUL HOROWITZ Well, you know, how about three or four,
equally spaced…
ALAN
ALDA Well, yeah, that would be a big eureka. But I mean
if you got a second flash, wouldn't your hair start
to stand up on the back of your neck?
PAUL
HOROWITZ Yeah, well, we probably have an object with
two flashes, so I'd better be cautious about hair standing
on end.
ALAN
ALDA You think you have one…
PAUL
HOROWITZ Well, we have to look at the data. But I think
we've seen objects with a couple of flashes. I should
say that the fuzziness in my statements here have to
do with the fact that in the summer, when humidity is
high, these detectors start to show artefacts, and in
summer we definitely have multiple hits on objects.
But we don't take it too seriously. We have to hope
that aliens will communicate with us wintertime, North
America.
ALAN
ALDA (Narration) Paul Horowitz is the first to acknowledge
that his way of looking for planets is a long shot.
But astronomers have growing confidence not only that
planets are commonplace in our galaxy, but that methods
for detecting them will soon allow us to look for Earth-size
planets -- and even for signs of life. Then we'll know
where to point our laser beams -- if we decide to say
hello.
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I,ROBOT
ALAN ALDA (Narration) To end our show on Life's Really
Big questions we've come to a man whose job it is to
wonder about such things -- a philosopher. The old stereotype
of philosophers of course is that they spend their time
counting how many angels can dance on the head of a
pin or just contemplating their navels. Dan Dennett
isn't that kind of philosopher -- though as a graduate
student in philosophy he did once spend some time contemplating
his arm.
DAN
DENNETT Somebody raised the question of what's going
on when your arm falls asleep and you can't move your
arm, and it seems this dead appendage, if you try to
move your arm, you can't. I thought, well that's a good
question, and I don't know the answer. And I was amazed
to see that the philosophers present not only didn't
know the answer but didn't seem to want to know the
answer or thought that maybe they should just think
about it. I thought, well, I don't think that's going
to work.
ALAN
ALDA Must have been a bunch of angels in there.
DAN
DENNETT Well, something. But I thought, well you know,
I just took the fact that I didn't know the answer to
that question, even though it was my arm, that maybe
the best route to your own mind is through the mind
of others, find some science, see how the parts work.
ALAN ALDA (Narration) Dan
Dennett has been trying to see how the parts work ever
since. In particular he's fascinated by how simple parts
can be put together to make complex things -- like people.
ALAN
ALDA I thought it was really interesting that you said
in one of your books that we were descended from robots
and composed of robots. In what way?
DAN
DENNETT If you think of an individual single cell as
a sort of little robot, like a bacterium is a robot,
we're descended from bacteria. And there's a trillion
and counting cells in your body and in mine. Each one
of those is clueless, it's not conscious, it's just
a little machine doing its job. And it's very myopic.
It doesn't know about the outside world, it just knows
about its surface, and very little about that: just
a few inputs and a few outputs. So you have a trillion
myopic robots with different powers, with different
jobs, different specialties. You put them all together
just right and you get a human being. Or an elephant.
Or an oak tree.
ALAN
ALDA Yeah. And before you got the human being, at least
in the course of the history of our planet, you got
a lot of other animals, and we think we're distinguished
from them. We keep trying to find ways in which we're
distinguished from the other animals. How would you
say we are, or are we?
DAN
DENNETT I think one of the really fascinating and also
frustrating controversies that's been running for centuries
concerns, well, are we just animals or are we really
different from animals? And the answer is, we are just
animals, we're mammals, but we really are different.
And primarily what makes us different is human culture.
And primarily what makes that possible is language.
What language and human culture let happen was just
an explosive capacity to know. We have created this
vantage point, where we, and we alone can sort of look
back and say, "wait a minute, I'm not so sure that the
highest good in life is procreating and replicating
more of my kind. I think I'd rather be a poet or I think
I'd rather join a monastery or be a scientist or who
knows what…"
ALAN
ALDA (Narration) For Daniel Dennett, nature -- with
its mindless little robots exquisitely assembled into
trees or birds or people -- is a source of endless wonder.
And nothing is more wonderful than the fact that we
can wonder -- a human gift denied to even the most appealing
of the creatures with whom we otherwise have so much
in common.
ALAN
ALDA When you see a dog lying in the sun, choosing that
one little spot on the living room floor, there's this
terrible urge to think the dog has chosen it, the dog
is aware of it, or the dog is looking out the car window,
seeing sights. Looks like enjoyment.
DAN
DENNETT Sure, I think it is.
ALAN
ALDA So there's some kind of thought going on.
DAN
DENNETT Oh, yeah. Certainly. I think that more complicated,
so called higher animals, mammals, birds, do have many
of the properties that we have in our minds. They also
lack some. In particular, they lack the sort of elbow
room to reflect on their own reactions to things, so
that they can feel pain and they can anticipate pain
to some degree, but they can't sort of dwell on it the
way we can. And the same goes for pleasure. I think
one of the prices that we pay for being capable of multiplying
our suffering through reflection and reliving and anticipation
is that we also get to have more joy. We get to think
about our lives and our prospects in a way that no animal
can.
ALAN
ALDA So that implies that we have some kind of freedom
of choice. And do you feel we do?
DAN
DENNETT Yes. I think that human freedom is as different
from the sort of freedom that other species have is
human language is from say, birdsong. Yeah, the bird
can fly wherever it wants, but it doesn't have very
expansive desires. It doesn't have a vision of what
life could be that makes freedom like our freedom such
a big deal. It's not such a big deal because it doesn't
realize what the options are. It doesn't really have
any way of grasping even the wonderfulness of what it's
doing. But with us it's different. I mean, we could
dream of flying for hundreds of years, for thousands
of years we could dream of doing what the birds do.
Now we can do it.
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