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Neil deGrasse Tyson is used to wearing a lot of hats. He is a
leading astrophysicist, the director of the American Museum of
Natural History's
Hayden Planetarium, a
columnist for Natural History Magazine, and the author or
coauthor of six books. As host of NOVA's "Origins" miniseries, Tyson
donned yet another hat, one that forced him to suppress his
customary outspokenness to serve as dispassionate guide on a journey
into the mysteries of the universe, the Earth, and life itself. In
this interview, Tyson returns to his old self, holding forth on why
he's not convinced there's intelligent life beyond Earth, why he
feels role models are overvalued, and how he copes with the
astronomical numbers that swirl around his head every day.
The start of everything
NOVA: What makes the study of origins so hot right now?
Tyson: Well, one thing that distinguishes us today from the
discoveries of the past is the extent to which the exploration of
the universe has become multidisciplinary. It was unthinkable not
long ago that a biologist or paleontologist would be at the same
conference as an astrophysicist. Now we have accumulated so much
data in each of these branches of science as it relates to origins
that we have learned that no one discipline can answer questions of
origins alone. It requires the additional insights that one gets by
merging not only the questions, but the answers, among scientific
disciplines.
Now, for example, when you look for life on Mars, you need the
astrophysicist to characterize the environment in which the planet
is found. You need the chemist to understand the chemistry of the
soils. You need the geologist to understand the rock formations. You
need the biologist, because no one else will know what life will
look like. You might even need a paleontologist to look for life
that doesn't exist there today but might have left fossil remains.
NOVA: It's hard to imagine scientists in such diverse
disciplines working well together. Do they?
Tyson: Initially it was like a shotgun wedding, where you'd
say, "Well, I guess we have to talk to each other." And scientists
in different disciplines don't speak the same language. They publish
in different journals. It's like the United Nations: you come
together, but no one speaks the same language, so you need some
translators.
“The moons of the solar system may be more interesting than
the planets themselves.”
But in the end, what happens is that new fields of astrobiology and
astrogeology and astroparticle physics arise, and they begin to
develop their own language that represents the intersection of the
two—say, between astrobiology and biology. That's when you
know you've created a new subdiscipline, or even a brand-new
discipline.
NOVA: What are some of the most exciting recent discoveries
in origins science?
Tyson: I would say one, we nailed the age of the universe.
Two, we have measured the existence of dark matter and dark energy.
Even though we don't yet know what they're made of, we know we can
measure the effects they have on the origin and evolution of the
universe. Another is the discovery that the moons of the solar
system may be more interesting than the planets themselves.
NOVA: How so?
Tyson: It's contrary to our earliest expectations. We used to
think, Our moon is dry and barren, so why should we believe anybody
else's moon is interesting? But if you look at the moons of Jupiter,
for example, you find that one of them, Europa, is covered with ice,
and below the ice is an ocean of water that is maintained in the
liquid state by energy pumped into it from its orbit around Jupiter.
Where there's water on Earth, you find life as we know it. So if you
find water somewhere else, it becomes a remarkable draw to look
closer to see if life of any kind is there, even if it's bacterial,
which would be extraordinary for the field of biology.
NOVA: The Cassini spacecraft has just reached Saturn, whose
moon Titan is of special interest too, right?
Tyson: Yes. Of Saturn's 31 moons, Titan is especially
targeted for its richness in organic compounds. That moon has its
own probe, the Huygens probe, which is a deployable subprobe
attached to the main Cassini spacecraft. The Huygens probe will
plunge through the atmosphere—because Titan has an atmosphere
for goodness sake! And it might have oceans, not of water but of
liquid methane. You can only begin to imagine what kind of
interesting chemistry we might find and what forms any possible life
might take under such circumstances—perhaps life not as we
know it, but as we don't know it.
NOVA: What great origins-related discoveries would you hope
for in the coming decades?
Tyson: The discovery of life somewhere other than on Earth.
That is an unimpeachable first goal in our exploration of the
cosmos. And what's fascinating is the question of whether that life
has DNA. It's a fascinating question, because either DNA is
inevitable as the foundation for the coding of life, or life started
with DNA in only one place in the solar system and then spread among
the livable habitats through panspermia. Panspermia allows life on
one planet to be thrust back into space by some meteor impact that
sends a little shock wave and flings a rock to escape velocity. If
you have stowaway bacteria on that rock, they could easily travel
through space, particularly the radiation-hardy bacteria we know
exist. They can land on and seed another planet, thereby not
requiring that you have to create life from scratch multiple times
and in multiple places.
Another possibility is that the life has encoding that has nothing
to do with DNA. That would be more important for biology than
finding other life with DNA, because it would be a way to encode
life that no one has dreamt of before.
NOVA: What about as an astrophysicist? Do you have hopes for
specific discoveries?
Tyson: I want to know what dark matter and dark energy are
comprised of. They remain a mystery, a complete mystery. No one is
any closer to solving the problem than when these two things were
discovered.
It may be that the answer to those questions has implications
elsewhere in science, and those are the best kind of discoveries,
because you're not just addressing the question you sought to
answer. It was the same with Einstein's relativity, for example. He
didn't start the day saying, "I'm going to explain this peculiar
behavior of Mercury's orbit." He had a whole other fish to fry. It
turns out, the oddities of Mercury's orbit naturally flow out of
this concept of relativity. That lends credence to the truth of the
idea, because it answers questions you didn't even think of asking
yet.
NOVA: Speaking of great discoveries, do you believe there's
intelligent life elsewhere in the universe and, if so, will we ever
detect it?
Tyson: I'm not convinced yet. I think that intelligence is
such a narrow branch of the tree of life—this branch of
primates we call humans. No other animal, by our definition, can be
considered intelligent. So intelligence can't be all that important
for survival, because there are so many animals that don't have what
we call intelligence, and they're surviving just fine.
“I see it as a real honor and privilege and duty to serve
others in their ambition to become scientists.”
I prefer to think of the search for life as the search for anything
that falls between single-celled bacteria and life that has some
kind of interesting purpose or function to perform. Then if we
discover life that doesn't seem to have as much of a purpose, but
it's still crawling around on the planet's surface, I think that
would be an extraordinary discovery that's undervalued given how
much Hollywood worries only about intelligent animals.
The sky is not the limit
NOVA: Having gone to the Hayden Planetarium as a boy, what's
it like to be its director now? A dream come true?
Tyson: No, I never dreamed that I'd be director of the
Planetarium. But now that I am, one of my greatest privileges is
signing the certificates of completion for classes taken by youths
and adults. I received these same certificates, signed by the head
of the Planetarium, when I was a kid taking classes. I see it as a
real honor and privilege and duty to serve others in their ambition
to become scientists the way scientists and educators served my
interest when I was young. To the extent to which it fulfills that
goal, my role in the Planetarium creates for me a significantly more
magnified pleasure in holding the position.
NOVA: What advice would you have for a budding
astrophysicist?
Tyson: It depends on their age. If they're really young, I'd
say the parents just need to get out of the way! So often parents
will interfere with the curiosity of their kids without even knowing
they're doing it. They'll interfere under the guise that the child
is misbehaving, when if you look carefully at the behavior of
children, in almost all cases it's exploratory.
If they're a little older, I'd say take full advantage of the
cultural resources that your municipality has to offer. Usually it's
free, or if it's not free, it's relatively cheap. My parents didn't
know much science; in fact, they didn't know science at all. But
they could recognize a science book when they saw it, and they spent
a lot of time at bookstores, combing the remainder tables for
science books to buy for me. I had one of the biggest libraries of
any kid in school, built on books that cost 50 cents or a dollar.
NOVA: In your memoir, The Sky Is Not the Limit, you
devote a chapter to discussing the challenges you and other
African-American colleagues have faced, just because of the color of
your skin.
Tyson: Yes, "Dark Matters."
NOVA: What advice would you give prospective young minority
scientists on how to cope with such challenges?
Tyson: What you need, above all else, is a love for your
subject, whatever it is. You've got to be so deeply in love with
your subject that when curve balls are thrown, when hurdles are put
in place, you've got the energy to overcome them. I can think of no
greater, more important need than this, because when I look behind
me, I don't see all that many [young minority scientists] coming
after me. It would be one of the greatest tragedies in our society
if that absence was only for want of support that could have
completely transformed their life's trajectory.
“It’s a very unnatural habit to understand what a
billion years is.”
That said, the racial challenges of today do not compare with the
racial challenges of yesterday. My father tells of not being
admitted into hotels. He had to go around to the back door, and he
couldn't use the water fountain. I have no counterparts to those
stories. But on whatever level it's happening, it can be corrosive
to one's personal integrity and one's sense of self. It's essential
to stay strong throughout all that and not let it get the best of
you.
Also, I think role models are overvalued as something important in
society. Typically, when you look for role models, you want someone
who has your interests and came from the same background. Well, look
how restricting that is. What people should do is take role models
à la carte. If there's someone whose character you
appreciated, you respect that trait. Someone whose moral fiber meant
something else, you respect that aspect. I think that will increase
the likelihood that you'll find a role model, amalgam though it is.
Cosmological questions
NOVA: What are you working on now in your work as an
astrophysicist?
Tyson: Right now I'm part of a major collaboration to look at
data from the Hubble telescope. It's a patch of sky that's being
imaged to very, very deep sensitivity levels to try to get the limit
of all galaxies in the universe. Once we resolve this, we're worried
about how galaxies cluster, how they respond to their own mutual
gravities, how they evolve over time.
NOVA: Do you have high hopes for the James Webb Space
Telescope, which is designed to study distant galaxies?
Tyson: Absolutely. That telescope, although it's been billed
as the follow-on to the Hubble Space Telescope, will not have the
same image appeal. But it will be unprecedented in its ability to
measure the formation of galaxies in the early universe, something
the Hubble can't do. The Hubble telescope can measure them in
different evolutionary states, but it can't see them actually
forming. And that's a big gap in our current knowledge right now,
how galaxies form. It doesn't have the sex appeal of the question
What is the origin of life?, but it's no less important.
NOVA: Regarding the origin of life, the astronomer Alan
Dressler has written that every atom in our bodies save hydrogen was
once at the center of a star. Can you explain that?
Tyson: Sure. The big bang endowed the universe with hydrogen
and helium and not much of anything else. That is, nine out of ten
atoms are hydrogen, about one out of ten atoms is helium, and there
are only trace amounts of other things. If there were no stars, that
would be the beginning and end of the universe.
But there are stars, and stars manufacture heavy elements from light
elements. They take hydrogen in and fuse the atoms to become helium,
and helium fuses to become carbon, and carbon fuses to become
silicon and nitrogen, and so on. Thus, elements other than hydrogen
and helium have no origin other than the centers of stars. And stars
not only manufacture the heavy elements, they also explode them into
space. Since life itself thrives on these heavy elements, we owe our
very existence to stars.
NOVA: One final question I've always wondered about: How do
you get your mind around the astronomical distances and
mind-boggling time spans you work with every day?
Tyson: You don't—you just grow accustomed to them. You
have to keep telling yourself how much bigger a billion is than a
million, how much bigger a million is than a thousand, and how much
bigger a thousand is than a few. You keep reminding yourself of
this, to the point where thoughts then occur naturally out of habit.
But it's not a natural habit. It's a very unnatural habit to
understand what a billion years is.
Consider the wealth of Bill Gates versus my own, for example. I'll
still pick up a quarter if I see it on the street. Now, let's take
the ratio of that quarter to my net worth—and I'm probably
kind of average for people who are fully employed—and figure
out what the corresponding amount would be to Bill Gates. It's like
$45,000! In other words, if Bill Gates is in a hurry because he has
to get to a meeting, it might be too much effort for him to bend
over and pick up $45,000 on the street. You need examples like this
to bring astronomical figures down to Earth, as it were.
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