BILL MOYERS:
This week on Moyers & Company, Neil deGrasse
Tyson on the new "Cosmos" and our dark universe.
NEIL DEGRASSE TYSON:
Science is an enterprise that should be cherished
as an activity of the free human mind because
it transforms who we are, how we live, and
it gives us an understanding of our place
in the universe.
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BILL MOYERS:
Welcome. It's been almost 35 years since PBS
premiered one of its most successful series
of all time: Carl Sagan's "Cosmos." Many
of you may remember, as I do, his elegant exposition
of the universe.
CARL SAGAN in Cosmos: A Personal Voyage:
Some part of our being knows this is where
we came from. We long to return. And we can,
because the cosmos is also within us -- we're
made of star stuff. We are a way for the cosmos
to know itself.
BILL MOYERS:
Over 600 hundred million people in more than
60 countries have now watched "Cosmos." But
in the decades since, the universe has kept
moving -- literally, moving in every direction
-- and so has science. And that's why "Cosmos"
is returning this spring, this time on National
Geographic Channel and Fox TV.
NEIL DEGRASSE TYSON in Cosmos: A Space-Time
Odyssey:
It's time to get going again.
BILL MOYERS:
Our guide is the astrophysicist Neil deGrasse
Tyson, America's most popular scientist, the
unabashed defender of knowledge over superstition
and clearly the rightful heir to Carl Sagan's
curiosity and charisma. So fasten your seatbelt
for a whole new interstellar journey through
tens of millions of years and hundreds of
millions of miles to the farthest reaches
of outer space.
Neil deGrasse Tyson is the Frederic P. Rose
director of the Hayden Planetarium at the
American Museum of Natural History here in
New York, where he narrates a breathtaking
new show titled "Dark Universe." I took my
12-year-old grandson to see it over the holidays
and we were mesmerized. Imagine: trillions
of stars, a hundred billion galaxies and light
traveling a hundred million years before
reaching us here on earth. 
That very planetarium, by the way, is where
Neil deGrasse Tyson, a kid from the Bronx,
age 9, first felt the universe subpoena him
to become a scientist in thrall to the night
sky. He's written ten books including this
memoir: "The Sky is Not the Limit" and this,
his most recent: "Space Chronicles: Facing
the Ultimate Frontier." Oh, yes, I almost
forgot -- "People" Magazine once voted him
the Sexiest Astrophysicist Alive! Welcome. 
NEIL DEGRASSE TYSON:
That was a few years ago, actually.
BILL MOYERS:
You only got it once.
NEIL DEGRASSE TYSON:
I know.
BILL MOYERS:
So no bragging rights, right? But you clearly
got more of the star stuff that Carl Sagan
said we're all made of. You just got more
of it than we did.
NEIL DEGRASSE TYSON:
Well, yeah, I've been touched by the stars
perhaps more frequently than others.
BILL MOYERS:
But you were just nine?
NEIL DEGRASSE TYSON:
Nine, nine years old. A family trip. My parents,
we were all native New Yorkers and my parents
knew well the value of all of the cultural
institutions of New York City. We went every
weekend to one or another of these institutions,
if not the zoo, the art museum, the many art
museums, the Hall of Science.
And our first visit to the Hayden Planetarium
for me-- by the way, I would ultimately go
as a school trip. But for family, I go there
and I sit back and I'm certain-- I love that
where you said I was subpoenaed by the universe.
I think I had no choice in the matter. I think
the universe called me. Because when the lights
dimmed and the stars came out when I was nine,
I'd never seen a sky like that in my life.
BILL MOYERS:
And you met Carl Sagan at 17, when you headed
to the Cornell?
NEIL DEGRASSE TYSON:
Yeah, well, so I applied to colleges knowing
full well that I was interested in the universe.
My application to Cornell, unknown to me,
was forwarded to Carl Sagan. He was a professor
of astronomy there. And I was deciding what
college to go to, he sent me a personal letter.
Man, I'm just a seventeen-- he's already been
on "The Tonight Show" and had best-selling
books.
Here's a personal letter said, "I understand
you're considering Cornell and you like the
universe, as do I. So why don't you come by?
I can give you a tour to help you decide whether
this is where you'll ultimately attend." So
I went up there, he met me outside the astronomy
building and gave me a tour of the lab.
One of my favorite memories is he reaches
back, didn't even look, just reached back,
pulled out one of the books that he wrote,
and then signed it to me and I said, "That
is awesome." And I said to myself, "If I'm
ever in a position of influence the way he
is, then I will surely interact with students
the way he has interacted with me, as a priority."
BILL MOYERS:
Do you remember seeing "Cosmos" when it first
aired?
NEIL DEGRASSE TYSON:
Yeah, but I was-- by then, I was in graduate
school. So it was... it didn't influence me
the way it influenced others, because I was
already established. But what it did tell
me was that there was an appetite out there
for science, if it's delivered in a way that's
compelling and that's warm, that's compassionate,
that is as though the person who is bringing
the science to you is sitting next to you
on the living room couch. And I thought, "That
bedside manner is something that more science
expositors should be doing." And I've used
it kind of as a model for me going forward.
BILL MOYERS:
So what are we going to learn about the universe
from your "Cosmos" that Carl Sagan couldn't
have known about? Well, let me put it this
way: if Sagan were around to see your series,
what would he learn about the universe that
was unknowable 30-some-odd years ago?
NEIL DEGRASSE TYSON:
Yeah, so that's a good question. So you need
to think of "Cosmos" not as a documentary
about science. By the way, since then, there
have been many documentaries about science.
And it's quite a fertile way of delivering
the viewer to the frontier, or bringing the
frontier to the viewer. So that's not the
issue here. Because we all remember "Cosmos"
and so many of these other documentaries maybe
lived their moment, but then they fade.
Why did "Cosmos" not fade? It's not because
it brought you the latest science. Although
it also did that. It's because it displayed
for you why science matters. Why science is
an enterprise that should be cherished as
an activity of the free human mind. Because
it transforms who we are, how we live, and
it gives us an understanding of our place
in the universe. And it's these states of
mind that you carry with you for the rest
of your life.
So in the new "Cosmos," that we are continuing
this voyage. We're continuing this epic exploration
of our place in the universe. We have other
stories to tell beyond the ones that went
on back then. Yes, right now, we are steeped
in the ignorance of dark matter and dark energy.
At the time of the original series, there
were no known planets outside of those orbiting
the sun. We suspected they were there, but
right now, we're rising through 1,000 planets
happily orbiting stars that are not the sun.
So these are not-- that's not simply new science.
It's new vistas of thought and imagination.
BILL MOYERS:
That place in the universe you talk about,
as you know, scares some people. Someone once
told Sagan that they didn't like astronomy
because it made them feel small and insignificant
in comparison with the grandeur of the universe.
It clearly didn't affect you that way.
NEIL DEGRASSE TYSON:
Well, it depends on what your ego is going
into the conversation. If your ego starts
out, "I am important, I am big, I am special,"
you're in for some disappointments when you
look around at what we've discovered about
the universe. No, you're not big. No, you're
not. You're small in time and in space. And
you have this frail vessel called the human
body that's limited on Earth.
If you have no ego, if you just want to explore
the world, look what happens. Here's-- the
conversation goes differently. You learn,
oh, the molecules and the atoms of those molecules
in my body are traceable to stars across the
galaxy that have lived their lives, manufactured
these elements, exploded them into the universe
from which new generations of star systems
were formed. So I look up at the night sky,
I don't feel small, I feel large. I feel connected
to the universe. It's not just we here on
Earth, and that's there. We are one. And that
link for me is one of the most profound discoveries
of modern astrophysics. And if that, that
should not make you feel small, that should
make you feel large.
BILL MOYERS:
At your planetarium show, which I went to
the other day just over the holidays, it--
I did feel small sitting there, looking up
at a hundred million light years coming at
us. But I also felt significant, the very
fact that my grandson and I are here in this
universe together is not insignificant.
NEIL DEGRASSE TYSON:
Not only that, if the human mind applying
known laws of physics to the universe allows
us to even come with an understanding of what's
going on out there.
BILL MOYERS:
Have we figured out our galaxy?
NEIL DEGRASSE TYSON:
So yes and no. All right, so the yes part
is we've got some laws of gravity and optics
and motion and yeah, we can use our knowledge
of physics and our knowledge of the frontier
science to land this probe on Mars within
a few meters of the target spot. This is tens
of millions of miles away, all right? There
is no golf shot that's that accurate, all
right?
Not even a hole-in-one is as accurate as what
this shot is, okay? So what we do know that
has been tested works. And that's quite a
state of empowerment. But there's a saying
where as your area of knowledge grows, so
too does your perimeter of ignorance. Because
this is the boundary between what you know
and what you do not know outside of that area.
So we didn't even know to ask why is the universe
accelerating against the efforts of gravity
until we made the measurement that it was
so. So before 1998, we couldn't even ask the
question, we didn't even know to ask the question.
So there's no sign that everything will ever
be fully known, because this moving frontier
continues to bring us more questions.
So can we measure how ignorant we are? Perhaps.
We know that what we do know about the universe
comprises 4 percent of everything that drives
it. 96 percent of what's driving this universe
in the form of dark matter and dark energy,
we have no idea what--
BILL MOYERS:
How do you know that it's 4 percent? Because
you haven't been able, have you, to measure
what we don't know?
NEIL DEGRASSE TYSON:
No, that-- so that's a really cool question.
In science, in astrophysics in particular,
in all sciences, you have the capacity to
measure something even if you don't know what
it is.
BILL MOYERS:
How so?
NEIL DEGRASSE TYSON:
Well, so, for example, you could measure the
fact that something is falling to the ground,
but not know what it is or what's causing
it or why. But you can measure it. You can
measure the sun moving across the sky, build
calendars based on that, and not even know
that Earth goes around the sun. You can--
and once you find out Earth goes around the
sun, that flips your point of view, but it
doesn't invalidate the concept of a year.
You can make all manner of measurements and
not know what's causing it. We measure this
thing we're calling dark matter. We measure
this phenomenon dark energy that's forcing
the universe to accelerate. When you add up
what we know with those two things about which
we don't know what's driving it, we only know
4 percent of what's driving the universe.
So that's humbling. That's humbling. The humblest
person in this world is the astrophysicist.
Because we are face to face with our ignorance
every single day.
BILL MOYERS:
But here's what puzzles me among other things
about you astrophysicists. The magnitude--
NEIL DEGRASSE TYSON:
I like the way you say that: "you astrophysicists."
BILL MOYERS:
Yeah, well--
NEIL DEGRASSE TYSON:
You guys.
BILL MOYERS:
Yeah, you guys. You're dealing, as I saw your
planetarium show, you're dealing with trillions
of stars, a hundred million or more galaxies.
How do you even imagine? How do you comprehend?
How do you get your mind around, to use the
cliché, numbers of such magnitude?
NEIL DEGRASSE TYSON:
We start early. I was--
BILL MOYERS:
At nine!
NEIL DEGRASSE TYSON:
Yeah, start them early. Think big early. In
fact, calculus, as a branch of mathematics
embraces the infinite. You sum an infinite
series of numbers or expressions. You start
thinking about large things early. And-- or
a large enumeration of objects early.
The way I like to think of it is you can give
analogies. So one of my favorites: do you
remember when McDonald's actually kept count
of how many hamburgers they sold?
BILL MOYERS:
Like the national debt --
NEIL DEGRASSE TYSON:
Exactly. And they had an interesting sort
of their own version of a Y2K problem. Because
when they got to 99, there was not a slot
for a third place. So there was no room enough
to put one, zero, zero. So many of them just
got stuck at 99 billion. So, I did the calculation
for 100 billion hamburgers.
If you had-- if you laid them end to end,
you could go around the Earth, like, 32 times.
Around the Earth, end to end. And then with
what's left over, after you've done that,
you can stack them to the moon and back with
your 100 billion hamburgers. And that's about
how many stars there are in the universe.
BILL MOYERS:
How much Pepto-Bismol would you need to deal
with that?
NEIL DEGRASSE TYSON:
Didn't do the Pepto-Bismol calculation. So
it's fun to think of large numbers in these
other contexts. And of course, there are numbers
larger than anything that enumeratable in
the universe. The number of googol, back when
googol was only a number, not also a corporation,
googol is a one followed by hundred zeros.
That number is larger than the account of
particles in the observable universe.
So there's nothing in the universe that you
can count that will add up to a googol. So
what I did as a kid, you just have fun with
numbers. And so when big numbers show up in
the universe, I say, "Yeah, give me more."
And what worries me is that when the debt
goes to a trillion dollars, or possibly a
quadrillion dollars, the national debt, I
hope it's never a quadrillion, but when it
gets there, do people really know how big
that is? I don't think so.
BILL MOYERS:
They don't.
NEIL DEGRASSE TYSON:
So we're handicapped by not knowing, not being
able to think creatively about how large these
numbers are.
BILL MOYERS:
I think you make me realize what I was experiencing
there in the planetarium. When you started,
you said, "We're not going to focus on what
we can see, stars and planets, moons and nebulae,
we're going to focus on what we can't see."
And it was-- it is?
NEIL DEGRASSE TYSON:
Dark matter. That's the audacity of the show.
I don't know any other show that said, "We're
going to make as the topic, as the central
theme, something about which we know hardly
anything." And that was not only a scripting
challenge. The writer here was Timothy Ferris.
BILL MOYERS:
Very informative, he did--
NEIL DEGRASSE TYSON:
I'm a fan of his work from way back. And so
there's a scripting challenge, there's a visualization
challenge. Our Director of Astrovisualization,
which is a really cool title if you ever want
one, I think, is Carter Emmart. These are
people-- he's a scientifically-literate artist,
a visualizer.
And so you bring this, and others, you bring
this talent together. You say, "Here's something,
we don't know what it is. But it affects other
things. Let's see how the rest of what we
know can proxy for that which we do not know."
By the way, this is how we know a black hole
is out there. You can't see a black hole.
But you see what effect a black hole has on
everything-- it wreaks havoc on its environment.
So dark things have a way of manifesting themselves.
BILL MOYERS:
Dark money as well. Dark energy, dark matter.
How do they differ?
NEIL DEGRASSE TYSON:
Well, unfortunately, they have similar-sounding
names. And since we really don't know what
either of them is, they-- I don't think we
should've named them. We should've given then
fake names until we understood them. I've
been voting for, Fred and Wilma. Something
that doesn't give you any cosmic bias, all
right? So I can tell you simply what dark
matter is. But don't think of it as matter.
I don't want to-- I'm concerned--
BILL MOYERS:
Like this table.
NEIL DEGRASSE TYSON:
I don't-- we don't know what it is. So I don't
even want to use those two words. If anything,
it's dark gravity. Because we look in the
universe, and we see the effects of gravity,
and they say, "Let's add up all the stars
and galaxies and planets and comets and black
holes, everything we know about, to account
for this gravity that we see."
We account for one-sixth of the forces of
gravity we see in the universe. There is no
known objects accounting for most of the effective
gravity in the universe. Something is making
stuff move that is not anything we have ever
touched.
BILL MOYERS:
And that something you call, for lack of a
better term?
NEIL DEGRASSE TYSON:
Dark matter. But that even implies it's matter.
What it truly is is dark gravity. Boom. That's
a problem that's been around since the 1930s.
It's the longest-standing, unsolved problem
in astrophysics. So now, dark energy, we look
out in the universe, and we expect to see
the universe-- our universe is expanding.
We've known this since Hubble, the man Hubble,
there was a man called Hubble, before he became--
BILL MOYERS:
An astronomer.
NEIL DEGRASSE TYSON:
Before he became a telescope back in the 1920s.
And Edwin Hubble, he discovered not only that
our galaxy is one of many, he discovered that
galaxies are scattering apart from one another.
This was the expanding universe in 1929. So
when you reveal this, you say, "Okay, if we've
been doing this for a while, all those gravities--
all those galaxies are going to feel each
other and they're going to ultimately want
to slow us down, in this expansion."
So you go out to measure that. And that act
led to a measurement that no one believed.
That, initially, that the universe is accelerating.
It's not slowing down, it's speeding up. These
measurements were made back in the 1980s--
back in the 1990s. A Nobel Prize has now been
awarded for this discovery, just recently,
a couple of years ago. The discovery papers
were in 1998. So we don't know what's going--
some mysterious pressure in the vacuum of
space, acting opposite the force of gravity,
we don't know what it is. But we can measure
its effect.
BILL MOYERS:
So you measure it by measuring its impact
on something else?
NEIL DEGRASSE TYSON:
Precisely. An impact on the 4 percent that
we can measure.
BILL MOYERS:
So it's the pressure that's expanding the
universe?
NEIL DEGRASSE TYSON:
Something, use the word pressure, something
is making the universe accelerate again. We
know why we got-- we had a big bang! Big Bang
put everything into motion. I'm good with
that. We're good. It's like me tossing a ball
up into the air. It's moving upward even though
it's slowing down, okay? Gravity is slowing
down that upward motion. We expected gravity
to be slowing down the expanding universe.
The opposite is happening. We don't know what's
causing it.
BILL MOYERS:
What is the practical difference it makes,
whether or not we find out what dark matter
and dark energy are?
NEIL DEGRASSE TYSON:
If you were around in 1920, maybe you would've
been saying, "What's the practical difference
of measuring the behavior of atomic nuclei,
or atoms? We can't see atoms. Why do I care?
This is just wood. This is a wood table. I'm
in a leather chair. I'm good to go. Why are
you investing so much energy, so much brain
energy on understanding what's in the middle
of an atom? That seems like a waste of this
brilliance."
In the 1920s, in addition to discovering we're
not the only galaxy in the universe, and that
the universe is expanding, that's a watershed
decade. Because in that decade, quantum physics
was discovered. And perhaps if you were around
asking me that similar question then, you
would've questioned the whole enterprise.
Yet today, a third of the GDP of the world
is generated on the creation, storage, and
retrieval of information.
And the entire IT revolution cannot exist
without an understanding of what's going on
inside the atom. It is a quantum physics phenomenon.
So you ask me, "Of what value?" I have no
idea what value. Come back in 50 years, we'll
have this conversation, and you'll pull up
the tape, and I will show you asking me of
what value is the knowledge of how that works.
BILL MOYERS:
One thing I took away from your planetarium
show is that dark energy, as you just said,
is responsible for the increasing rate at
which the universe is pulling itself apart,
right?
NEIL DEGRASSE TYSON:
Yes. So I'd rather word that differently.
I would say the universe is accelerating.
We call that dark energy. So you're saying
dark energy is responsible for that. There's
something, whatever it is, we call it dark
energy, that's what, that's our placeholder
term, to describe what we observe, the acceleration
of the universe.
BILL MOYERS:
Well, I'm glad you explained that. Because--
NEIL DEGRASSE TYSON:
By the way, there's-- nothing known will stop
this. So there's been some concern that maybe
space does not have the flexibility necessary
to allow such rapid expansion. And might space
tear in some way previously unimagined, and
what does that even mean? What-- does the
question even have validity?
BILL MOYERS:
You mean the House of Representatives cannot
pass an act that will stop this? As they would
like to? No, seriously, I was going to ask
you, because if the universe, that term--
if that phrase, if the universe is pulling
itself apart, does it ultimately disintegrate?
Does it ultimately collapse?
NEIL DEGRASSE TYSON:
No. There's no evidence to say that we will
ever recycle ourselves. All evidence points
to we're in a one-way trip to oblivion. So
the universe expands, the temperature of the
universe drops, all stars eventually will
run out of fuel. So the stars, one by one,
in the night sky will turn off. And in the
extremely distant future, a quadrillion years
into the future, there'll be no light coming
to us in the day or night sky.
And, because all stars would have died. And
all gas clouds would've made stars that would've--were
going to make them, and there'd be no more
new stars created. And so that the universe
will end not with a bang, but with a whimper.
And not in fire, but in ice.
BILL MOYERS:
But don't worry; we will not leave you out
in the cold. We'll be back, in fact, next
time with Neil deGrasse Tyson to talk about
whether scientists are discovering God in
the dark matter that holds the universe together
even as it hurtles ever outward from us.
And in the meantime, there's much more at
our website, BillMoyers.com. I'll see you
there and I'll see you here, next time.
