Transcriber: Helena Galani Reviewer: Ariana Bleau Lugo
When I was a boy, my dad used to pick me up after school.
I was about 11 years old, in Geneva, Switzerland,
and he'd drive me across town
to the site of the Large Hadron Collider, in Geneva,
which was called the European Center for Nuclear Research, at the time.
It's where they discovered the Higgs boson a few years ago.
There was a remarkable man there, Rafael Carreras,
who used to give weekly lectures called in French
'Science Pour Tous' which means 'Science for Everybody'.
There were people from all walks of life who attended these lectures.
There were school boys like me, janitors at CERN, professors, housewives.
A whole mix of people were attending that stuff who gave up their lunch hour.
They were also working people.
There were two things that struck me about these lectures.
The first thing was that people were doing this not for any personal benefit,
there was no credit, no remuneration,
but they were just doing it because it interested them.
I thought this was rather wonderful and sort of put a light bulb in my head
that maybe you could go through life doing what interests you rather than
what doesn't interest you in order to, then, do what interests you.
You could short-circuit things. (Laughter)
The other thing I liked is, Dr. Carreras was always encouraging.
I'd often go and ask him questions and so on.
He never looked down on me as a kid.
There weren't any stupid questions.
You could go and ask him anything
and there was always stuff to be learned
and I liked this environment so much,
I think it set me on a path to ending up here
where I am a professional scientist talking to you.
Even before then, my dad used to read me stories
from the 'Winnie the Pooh' books
and there's a picture here of Winnie the Pooh and Piglet
searching for a Heffalump.
A Heffalump's a very rare and unusual thing
that had almost, maybe never, been seen.
But they got circumstantial evidence here.
They' ve seen footprints in the snow
and this has encouraging them,
maybe if we continue work a little bit harder,
maybe we could find this thing.
So the basic difference betweeen me and Winnie the Pooh in this picture
is that he's looking down and I look up for a living.
So, we scientists, in particular,
the subject of this talk is to look for the first stars
and galaxies to form after the Big Bang.
They're rare and unusual objects. We think they are very different
to the stars and galaxies that we can see around us today.
But we think they are there.
We have circumstantial evidence that makes us think
that they are there so the quest is worth following.
So I've told you these two anecdotes maybe a bit from my life
in order to give the idea of a timeline also
that I sit here today looking in my past
as we all can towards when I was born,
and you can see significant events that shaped your life.
What's remarkable is that we can do the same thing for the Universe.
So the Universe originated in a Big Bang.
We don't know exactly what banged or how it banged,
although, a couple of weeks ago, we had some indications
if you followed the science news.
But we know when it banged to amazing accuracy.
So, we know the Big Bang was the creation of time and space.
Matter and light happened 14 billion years ago.
We know the exact number to 1% accuracy.
As I was bouncing back into my past at the start of this talk,
we can do the same thing here in astronomy
because light travels at finite speed.
So when we look up at the sky,
we' re actually looking into the past.
And for most cases it's not so relevant.
In the case of the moon it's like 2 seconds.
When you see the moon, you see it as it was 2 seconds ago
because that's how long it takes light to reach us from the moon.
Naked eye stars that you can see
if you go out in the desert away from the street
that may be a few thousand years.
You see them as if they were a few thousand years ago.
But the most distant object you can see with your naked eye
which is the Andromeda galaxy
pictured here seen through a telescope,
is actually 2.4 million years ago.
So the light has taken 2.4 million years to reach you.
Even without the aid of the telescope you can see this object.
If you wanted to know what it looked like today,
you'd have to wait another 2.4 million years.
So, the history of Astronomy has really been the history of developing
telescopes and technology to be able to push further out into space
and see even more distant and remarkable things.
This is a picture of an object known as a comet cluster,
many thousands of galaxies like the Milky Way.
It's so far away that it's seen 250 million years ago, roughly speaking.
So 250 million years ago,
here there was a deep sea, a deep inland sea.
We know this because we see the Kaibab limestones of Red Rock.
We see these also, just downstream from Glen Canyon down at Lee's Ferry.
These tell us the idea of what was happening here was very different.
It wasn't a desert. It was an inland sea.
But we don't see the thing itself.
We have circumstantial evidence, the rocks.
But here we're seeing the thing itself
as it was 250 million years ago.
So I've drawn sort of a timeline
on the slide we have today on the Big Bang.
The green arrow shows you when the Earth formed.
So the Earth is a relatively recent addition to the Universe.
It's only been there for a third of the existence of the Universe.
For two thirds of the time our solar system wasn't even there.
So how far back can we actually look with our technology?
I've drawn here a little red square on the slide
which shows the field of view
of the best instrument that we built to be able to do this --
you've certainly heard of it -- it's the Hubble Space Telescope.
The Hubble Space Telescope has a very small field of view.
In other words, it takes a very small picture of the sky at a time,
about 100th of the size of the moon.
If you want to picture that, it's like coding a grain of sand at arm's length.
It's a very, very small part of the sky.
And scientists had the idea to try and probe back in time
would be to take a picture of the sky
but to take two weeks to observe one part of the sky.
This was a remarkable idea to look at a nondescript, not a part of the sky
we'd thought it wasn't anything interesting,
but just to see what's out there.
What we found was remarkable.
Here's one of the most famous images ever taken in astronomy.
It's a Hubble Ultra-Deep Field.
In an area the size of the grain of sand held at arm's length,
you see ten thousand galaxies here.
They're not stars in our Milky Way.
They're separate individual galaxies, like our Milky Way.
In this image, about ten of them are seen as they were
13.3 billion years ago,
which is to say the light started on this journey
long before the solar system ever formed.
For most of that journey, the Sun and the Earth didn't exist.
You know, the Sun and the Earth formed and then life evolved and so on,
we built telescopes and boom, we capture this light.
It's utterly remarkable.
But those are not the first galaxies.
Remember, we are looking for the first stars and galaxies.
This is one of the major scientific adventures, I think,
of the 21st century
which is going to play out in the next ten years.
So we sit here and we look at this Hubble Deep Field.
How do we select then the ten galaxies,
the one in a thousand galaxies that are the most distant.
It's so simple that I thought I'd just tell you today.
What we do is not a technical description.
We take a picture at visible wavelengths of the Hubble-Deep Field
The galaxies which can be seen in the infrared image,
but cannot be seen in the visible image, those are the ones.
There's just a few of them, there's just ten of them.
Those are the ones that are seen 13.3 billion years ago.
To summarize my story so far --
if I can get the next slide, there it is.
We sit here in the Milky Way and we look further and further back
with more sophisticated telescopes.
And we look further and further back in time
13.3 billion years so far with the Hubble.
But we have another piece of information
which is the cosmic background radiation.
The cosmic background radiation which is seen at radio wavelengths
tells us what was happening in the Universe
only roughly half a million years after the Big Bang.
We know there was a time from the staff,
the outermost shell that's colored green and yellow and blue there,
that there was a time when there were no stars and galaxies in the Universe.
That's what that tells us.
But it tells us another important thing,
which is that on its journey, the slide on its way to us
was modified by stars and galaxies,
the first generation of stars and galaxies
that we haven't yet detected.
That's a sort of Heffalump effect. The footprints.
We see the footprints of the things we're looking for
but we haven't seen the thing itself yet.
So in order to find these things that we're looking for,
we need to devise new tools.
The history of astronomy has been the remarkable improvements
we've been added for 400 years with the telescope.
Galileo's telescope had a lens about this big
and this is a next generation of telescopes being built in Chile.
This is a European Extremely Large Telescope --
running out of names for telescopes now. (Laughter)
But the mirror --
The mirror is about the size of this room
so it's a gigantic tool for looking back into space ever further.
As you saw from before, we need visible and infrared light
in order to study these objects.
In the infrared, we' re building
what is the successor to the Hubble Space Telescope
which is what's called the James Webb Space Telescope.
This is just one sixth of it shown here.
So it's a gigantic instrument.
It's so big that it won't fit into a rocket.
So they are going to have to fold it up like insect wings or something,
put it in there, send it out into space, take it out, unfold it
and then it's going to take what we hope
are the images of the first stars and galaxies.
It's also going to explore planets
and other things that are of great interest to us.
So, what do we expect to find?
The way we do astronomy is illustrated in this video here,
is astronomy and science is a constant dialogue, really,
between theories or our conjectures about the way things ought to be,
which is shown in the movie here,
and the way they actually are, which is shown in the stills.
So in the movie here, you can see two galaxies,
like the Milky Way and Andromeda that are on a collision.
This is a calculation done in a computer.
Once in a while, they freeze the movie
and because it's a computer simulation
you can view it any way you like,
and then they try and compare it,
to actual images of galaxies nearby
to see how good a job we have
at understanding interactions between galaxies.
In the case of the most distant stars and galaxies,
we've only done half of this.
We have our conjectures, but we don't have the observations.
So what can we expect to see? How is this going to play out?
Based on the history of astronomy,
I think I can best tell it with an anecdote.
Howard Carter, when they discovered Tutankhamun's tomb,
they were in a sort of narrow corridor
and he was the first to see the tomb in modern times,
and he had a candle and in the flickering light he could see
this vast array of treasures of gold and statues of animals and things.
The others behind him -- he didn't say anything,
and they were like: 'What do you see?'
And he said, 'Wonderful things', 'Wonderful things'.
And I think that's what we can expect
in our science in the future.
But as well as learning about the Universe
which is going to be tremendously exciting,
I think, science teaches a lot about our humanity, ourselves as human beings.
For those of you who don't know the Pooh story,
the punchline to this one is
they actually didn't find the tracks of the Heffalump, unfortunately.
They were looking at their own tracks in the snow.
But they learned something about themselves in this adventure
and about what they were.
We do this too, when we do science.
We learn our position in the Universe, but we also learn about ourselves.
And the European Center for Nuclear Research which has many --
several Nobel prizes have been awarded there.
I didn't tell you this far, it was built really
out of the ashes of Europe after WWII. Europe had been at war.
I am an immigrant from Europe.
For most of the 20th century for reasons that weren't clear,
but all these countries, for religious, cultural, ethnic reasons
were at each other's throats.
And the idea is maybe there is another way.
What if we work together?
What if people from these countries that had been at war
showed that by working together, overcoming their prejudice,
we can do good science?
And history of CERN has shown
that when you do this you can achieve wonderful things.
Wonderful things!
Thank you.
(Applause)