>> JOHN CARLSTROM: It's an honor
to be the speaker at the 526th Convocation of the University of Chicago.
Welcome student, friends, family, students. I want to start with
congratulations to the graduates. You will soon receive your well
earned degree from the University of Chicago. Several years ago you
seized an extraordinary opportunity and through your hard work,
perseverance find yourself here today. Not many have the opportunity
or the ability to do what you have done and you know it wasn't easy.
Many have invested in you, none more than you have yourself. And I
thank you. We all thank you for that. What have you learned?
Well, you've learned a lot beyond the facts that you probably will
forget soon. You have learned how to learn, the value of learning.
You have learned how to think. This has hopefully given you a deeper
appreciation of life, and given you more opportunities to be inspired.
You are ready to explore and to contribute. You're ready to seek your
path wherever it may lead you. Frankly this took me a long time. In
fact I'm still kind of working on that. But then again I didn't have
the benefit of a University of Chicago education. Today I want to tell you a few stories. I'm
going to start with a vague memory, to remind myself even, I had
a vague memory of my father coming home from work once and saying he heard
a news story where on the news they said that scientists had heard
the universe being created. I don't remember too much of that,
but somehow I buried that deep inside. I also remember my mother, who
was taking night courseses to get her degree at the time, coming home
and telling us what she is learned in classes, I remember her telling
us about the stars, galaxies and space and Einstein's outrageous, it seemed
to us, theories. It was a lot of fun to try to get our heads around
this. Space and time weren't fixed, they could be curved, they
could be mutable, relative. There were black holes. It was a lot of fun
and very inspiring. These are strange ideas to us of course. They're
far from everyday experience. But Einstein was a clear thinker.
Sign Einstein was able to distinguish and separate what was known
to be fact by observation and what was just assumed to be real. Right?
Taking that and taking what was the result of experiments at the
time, observation bes of the universe, led him to these really incredible
and unimaginable or outrageous, people would think, insights in
how the universe worked. We now know those insights and his results
were true. Our Subrahmanyan Chandrasekhar here at the University was one
of those masterful thinkers. I am lucky, indeed privileged all
these many years later to be studying the universe. That news story
my father heard must have been about the discovery of what's called
the cosmic microwave background. This is a discovery made by two
Bell Lab scientists. They found there was a glow of light, the universe
was glowing with light in all directions. It was light that was very
long wavelengths, what we call radio waives, which you can't see with
your eyes much as a result I expect that's how it got confused to be
hearing the universe rather than seeing the universe. They had discovered
the very first light in the universe. The fosal light from the hot
Big Bang has been traveling to us for nearly 14 billion years. This cosmic
mike back radiation is an amazing thing. Provides us with a glimpse
and view is to see the early universe 14 billion years ago. To a
time before stars had even formed. The discovery expanded our view of
the universe and gave us a tool to discover it. That's the tool I use
this day. Some of youed undergraduates maybe remember in PhySci classes
measuring the background. Using instrument similar to whats
Penzias and Wilson used. Wilson called me once and said how do you
do that? How is it that you have undergraduates at the University of Chicago
measure the cosmic microwave background? We want to do that at
Harvard. That call made my day, I can tell you.
It has taken decades, however, using ever more sensitive telescopes
and sensors to go beyond the detection of the cosmic microwave
background to actually develop baby pictures of our universe is with
enough sensitive that we can see these very faint features in the early
universe. And we have done that. The most detailed images
come from the University of Chicago led South Poletel scope
located on the driest desert on earth, the high and cold Antarctic
Plateau, there to take advantage of the clear skies. Working at the
South Pole is fascinating. It's cold. Probably you knee
that. It's actually colder than Chicago. Maybe you didn't know that.
Except for one or two days a year when we find that actually it's reversed.
But usually it's quite cold.
The most inspiring thing -- I should also point the views are just
amazing. It's like something you've never seen. Just ice, snow,
beautiful. But the most inspiring thing is not the views,
it's the people. There's about 200 people at the research station
during the awe stral sum he shall, about three months. And then
only a handful, 50 at most, decide to spend the night. The long winter
night there. And they keep can it going. They keep it going for nine
months, they cannot leave the station or come in. It's closed off.
There's no physical access whatsoever. Sthe all work together. They have a common
purpose and they all have a part to play. They share in the discoveries.
Which would not be possible without them. They are inspired and
they're inspiring. So what have we learned? Well, a great deal.
We have figured out what stuff makes up the universe, and amazingly,
the stuff we know about and stuff you can find in your textbooks
is a whopping few percent, 4 percent. We know the other stuff
is there. We even give it names. We give it names that inform -- informative
of our knowledge of it, we call it Dark Energy and Dark Matter.
Clearly there is a lot more to discover and to learn.
So we make these baby pictures, but what do they look like? And the
truth is they look like noise. But if you're educated and you can
appreciate this noise, the noise is exactly that that would be
predicted, it's beautiful. That which would be predicted by quantum
mechanics. What they are a picture of is quantum fuzz, which rules
physics on the scales that are unimaginably small. As somehow been
expanded to the astronomical scales and gives the seeds of all the
structure in the universe, including ultimately us.
Our alumni Carl Sagan famously said we are star stuff, referring to
the fact that most of the elements we are made out of were first made
in stars. We can now say we are quantum fluctuations. I agree, it's
not quite as -- might not sell as well, but it's an amazing fact.
Appears to be a fact, that we are the result of quantum fluctuations
all that long time ago. Let me tell you of another story. Roughly a
billion years ago in a galaxy far, far away, two black holes, like the
type predict bed by Chandrasekhar, began a death spiral orbiting each
other closer and closer. The extreme gravity of each hole warped and
distorted the space time around it and dragged it with it. And as they
circled each other the fabric of space emitted waves, what we call
grafgs waves waefs. Those Gravitational Waves spread out, moving at
the speed of light and carried away energy. The black holes collided,
losing energy -- I mean spiralled closer until their ultimate inevident
stabl catastrophic collision. They moved at a speed close to the speed
of light, and emitted a final burst of Gravitational Waves. Those
waves carried off more power during that brief time than all the light
emit bid all the stars in the universe. They then merged into a single
dark hole. That was one hell of an event. 40 years ago scientists
began to develop a method to try to detect Gravitational Waves with a
bold sum might say even outrageous goal of using them as a way to
observe the universe. They needed to figure out how to measure the
small and fleeting changes in space and geometries introduced by a
passing of a gravitational wall. It's a part intended to 1021. As if
your toes got closer to your head by a dimension of one trillionth the
size of an atom. And vibrated back and forth in maybe 100 Hz, a
frequency you can maybe hear if it's loud enough, for a fraction of a
second. Another way of looking at that is if you take the distance of
a star, not our sun, say Alpha Centauri, 4.4 light years, the change of
distance over that great distance of a width of a human hair.
Incredibly hard and difficult thing to do. And many thought
impossible. More than 1,000 scientists from 15 countries carefully and
meticulously refined what's known as intertermtry, engineered by
Michelson. They used an interferometer to measure distances and
bouncing laser light off 4 kilometer distant heavily stablized mirror.
After solving problem after problem, last fall they reached the stage
where they had sufficient sensitivity to hope to make a detection. It
was just in time. They turned their machines on, four days later,
those Gravitational Waves from that merging black hole a billion years
ago reached earth and set off their detectors. We heard on this on
February 11th. The whole wornd learned of it. We heard from our
colleagues, part of the discovery team, Professor Dan Holz and his
students, the same Hahn Holz that undergraduates nominated last year
for Quantrell Excellence in Undergraduate Teaching.
Once again our view of the universe has expanded with a new tool to
explore. In many ways we are now actually hearing the universe. When
I got home that day, I told my children all about it.
Astronomers will now begin to investigate the properties of black
holes directly and their role in the evolution of the universe. Maybe
decades from now your children will be measuring Gravitational Waves in
a PhySci lab at the University of Chicago. There's one more incredible
and energetic event, the most energetic event in the history of our
universe, which is the birth of our universe. Our model of the
universe, which fits all the existing data so well, predicts that in
the first fraction of a second after the Big Bang, and by that I mean
1035 seconds, what my colleague, Michael turner refers to as a jiffy.
In one jiffy Gravitational Waves, a whole background of distorted space
time should have been produced and left as a background. We believe we
know how to see that background now, by making some say outrageously so
presh urments of the background. We can use them to explore our
origins. We're starting the experiment. We have hundreds of
scientists from across the globe coming together. Hopefully you will
not have to wait too long to hear about the results but when you do
tell your children. What is the message behind these stories? You can
use your exceptional education, dare I say privileged education to make
a difference in whatever you choose to do. Please be bold. Know that
people working together can achieve great, even seemingly impossible
things. Go and make a difference. We're counting on you to do that.
In closing let me again congratulate you and thank you for all your
hard work. Many thanks to your families and supporters. Keep learning
and teaching. Be inspired and inspire. Whatever you choose to do, do
it well. Share your story. And please come back and tell us about it.
Thank you. (Applause)