Transcriber: Reiko Bovee Reviewer: Denise RQ
Thank you.
What I would like to share with you
is the fact that we are born of stardust.
That may sound poetic. It's not from a poem.
It's certainly not from the Bible.
It is a scientific result.
It's a result of our scientific knowledge of the universe.
Here's a picture of that stardust.
But before I pursue this story that we are born of stardust,
I would like to raise an issue which I think is very important.
And that is...
A question is buried in this scientific story.
And the question is a scientific question.
If we did come about, --we and the whole universe
through this process of an expanding, evolving universe
in which we are made of stardust--,
if that happened,
did it happen by chance or by necessity?
That question itself has, what I call a religious implication.
Because if it happened by chance, who needs God?
It just happened, and that could be true scientifically.
As a matter of fact, it's not from the best science we know.
If it happened necessarily, who necessitated it?
Who designed it?
So the God question is buried in what I call [a] scientific question.
But let's proceed to the scientific question.
From the Big Bang, the universe has been expanding.
This is a small slice of the universe.
And since the universe is 13.8 billion years old,
we are out here.
There's 14 billion [and] there's 15 billion.
Since the universe is 13.8 billion years old,
we, astronomers, are trying to look back
as far as we can to the Big Bang
to see the early universe.
We use Hubble Space Telescope and other big telescopes
on the surface of the Earth, and we take a picture way back here.
And what do we see?
That's what we see.
So, why am I so excited?
(Laughter)
On this one photo, there are only about 5 stars.
There's one, there's one...
Every other dot here is a galaxy.
So, let's sample a few of them:
There is an irregular galaxy, an elliptical galaxy, a spiral galaxy
like our own galaxy as we'll see in a moment.
A galaxy typically contains about 200 billion stars, like our galaxy.
The Sun is one of those stars.
Some galaxies contain more, some less.
But if this small part of the sky,
and what I mean by small part,
is this part of the sky
(is) about 1/20th of the thickness of my index finger;
because Hubble wanted to look as far as it can out into the universe.
So if this is such a small sample of the whole heavens,
we scan, we can't study the whole heavens, but we scan it,
and we do statistical studies,
and we come up with the fact
that there are hundred billion galaxies in the universe,
each of which contains two hundred billion stars on the average.
That makes 20,000 billion billion stars in the universe.
That's 2 with 22 zeros behind it.
Why is that important?
That's important because it makes the universe very fertile.
Why do the stars make the universe fertile?
Let's look at the tabletop of our galaxy.
This is our Milky Way, with a photo taken
at our observatory in Arizona. Here is Phoenix and Tucson.
What I am interested in, in this picture,
is not so much all the stars but these dark areas.
There is an enlargement of a piece from the previous slide
where we see all these dark areas scattered around here.
Why am I interested in them?
Because they are stellar wombs.
Within that dark gas, stars are being born.
And here is a star birth, actually happening from that dark gas.
As that gas collapsed, it began to heat up,
so it becomes this beautiful white and blue.
But each of these little pieces in this gas
is going to begin to collapse, so a cloud breaks up, the pieces collapse.
As they collapse, they raise the internal temperature
to tens of millions of degrees
and they turn on a thermonuclear furnace.
Don't run away from me.
Thermonuclear furnace is a very simple idea.
It's just that at very high temperature
we can convert hydrogen into helium.
We can take four hydrogen atoms and make one helium.
But when we make one helium it has less mass.
Where did that mass go to?
It became energy through the famous equation you all know:
E=mc².
So, a star lives by converting light elements into heavier elements.
And then, when it finishes this process, it collapses again
to raise the temperature even higher
to start converting helium into carbon
and then carbon into nitrogen.
So, depending on the mass of the star,
as it collapses,
it can raise the temperature high enough to make the next heavier elements.
But we have a distribution of stars around the mass of the sun.
We have distribution of stars that are much more massive.
So, we have all these stars, ten thousand billion billion stars,
constantly creating heavier elements.
But stars die!
This is a dying or dead star.
It's the famous Crab Nebula.
At the center of this Crab Nebula
is a neutron star, a dead very massive star.
But the important thing for what I'm sharing this evening,
is that this gas here,
blown out from the death of this star
is going to dissipate, difuse into the universe,
And from this gas, another generation of stars are going to be born.
And you can see from one generation of stars to the next
[how] we're getting ever heavier elements
built up in this fertile universe.
The Sun is a 3rd generation star.
And if it were not, you and I would not be here.
That's a scientific fact.
We are born of stardust
from a third generation star.
That's a scientific fact.
Around one star,
in these hundred billion stars in our galaxy,
this little grain of sand came to be. And it's a little grain of sand!
I mean it's one planet,
of eight planets around one star,
of a 100 billion stars in a galaxy
of which there are a hundred billion galaxies!
So it's a little grain of sand but it's very precious for many reasons.
But one of the reasons is this:
Not even we scientists reflect enough
about the amazing achievement of modern science.
Through physics, biology, chemistry, [or] mathematics,
we are able to put the universe in our heads.
In us, the universe is thinking about itself.
And when we think about the universe,
we typically get more questions than we get answers.
Here's again, one of the questions:
Did we come about by chance or necessity?
Well, I have to pause for a moment and explain what I mean "by chance."
It's very simple.
Two hydrogen atoms, in the very early universe, meet.
They have to make a hydrogen molecule;
that's the nature of chemistry, that's the nature of the universe.
But they don't, at this time and place,
because the temperature and pressure conditions are not correct.
So they wander throughout the universe, they meet trillions of times.
There are obviously trillions of hydrogen atoms from all of these stars.
What is the probability that will get a hydrogen molecule?
We can study that probability.
It's not just hand waving like I'm doing right now.
We can really study that.
When we study it, that's what I mean "by chance."
Around some stars it's more probable,
around other stars not.
But there is just a chance, it's not always necessary
unless the conditions are correct;
the pressure and temperature conditions necessary.
So what we have, very briefly speaking,
and not romantically, but scientifically speaking,
we have a dance in the fertile universe, of chance and necessity.
We have all these ingredients,
and they are building up ever more complex organisms,
because that's the nature of the universe.
So, let's now, with that in mind, ask the God question again.
So I am passing a little bit now, from what we know from science
to this implication of what we know from science.
To do that I ask you to look at what I call a "tree of the universe."
Everything that ever happened in the universe
from the Big Bang on, is on this tree.
The birth of my grandmother, my first toe,
the galaxies, the stars,
those atoms that never made a hydrogen molecule.
So all those processes that chance would not allow to happen,
are on this tree.
But blow a quiet breeze through this tree,
and what will you see?
Knock off all the dead branches and dust,
and you will see, inevitably, something like this.
I used two words that are very important: "inevitably."
I didn't say: "«necessarily» something like this,"
because if I did, I contradict everything I've just said.
And while I've contradicted myself on more than one occasion,
I prefer not to do that.
(Laughter)
So I say "inevitable," because that's the nature of the universe.
And I say "something like,"
because since there are chance proceeses involved,
this could be slightly different.
Why is the human being at the top of this tree?
Because we don't know what else to put there.
The human being is the most complicated machine
that we know. That is the human brain.
Actually, as all of you know,
it's not a tree of life, it's a bush of life.
But for my purposes I showed a tree.
And in that bush, we animals are up here,
at the upper right-hand side of this slide, on one of the branches.
Well, let's get then.
Did God do it?
I don't know!
(Laughter)
(Applause)
Thank you.
It is a long way from Rome and the Vatican.
(Laughter)
No, I can not know whether God did it or not.
And any scientist, like myself,
that inserts God or excludes God, is not doing science.
Pure science seeks
the natural explanations for natural events.
So I cannot talk about God within science.
But, if I talk about God
from my scientific knowledge of the nature of the universe,
that I've described to you,
the universe is very dynamic.
It has chance and necessary processes.
It's very fertile this very dynamic universe.
Can I ask the question?
If I believe that God created the universe, and I do,
what kind of God [that] I believe created it,
would make the universe like the one I know as a scientist?
To me that's a valid question.
And to me it has an answer: it's not this kind of God.
This is a beautiful piece of art,
but it's a God that's designing the universe very carefully,
laying out things in the universe.
But the universe [as] we know it today,
God cannot have designed it,
or if he did, he did a damn poor job!
(Laughter)
We have tornados, we have hurricanes, we have leukemia...
So, to take God as a designer God,
from the scientific knowledge we have of the universe, is really not fair.
God's relationship to the universe, to me,
is very much like a parents' relationship to a child.
You discipline a child,
you teach a child that if you throw sand up,
make sure the wind is not blowing your way
or you are going to get it in your eyes.
You have to teach a child, but you have to let the child go,
like God lets the universe go.
So, to me, I come back to the question:
Did God do it?
I don't know from science. But if I'm a religious believer
and I think about what kind of God could do this,
I think it's a magnificent God.
God did not create a washing machine or a car.
He created a very dynamic universe.
And because that's the case, I end with a final question:
Why is it, that there seems to be
a continuous, perduring sense of a conflict
between science and religious belief?
I really don't understand it from my personal sort of career.
And I wonder how many of you understand it.
If you do understand it, would you let me know?
Why in American society, do we still have
--well in societies in general, but certainly in American society--,
do we have this idea
that there's a conflict between religious belief and science?
Thank you very much for listening. Have a good evening.
(Applause)