Secrets of the Universe (2022–…): Season 1, Episode 8 - How did the Universe Begin? - full transcript
Scientists are brushing up upon age old questions
that used to be the purview solely of theologians.
Last century, a radical idea about the origin
of everything was born.
It would become the most famous theory in all of science.
Fred Hoyle, in rather derogatory way,
described it as a big bang.
As the big bang theory evolved,
it made predictions that were only confirmed by accident.
This radiation was discovered using this radio antenna
that wasn't even looking for it.
What was coming out of this thing
had to come from somewhere.
Had science discovered the moment of creation?
We're looking at the infant pictures of the baby universe.
But the big bang theory had its challenges.
There were several problems
that could not be explained without conspiracies.
Cosmologists were forced to propose
a mind-blowing scenario to fix the difficulties.
I wake up my wife and I said,
"I think that I know how the universe was born."
They claimed that the universe expanded
by trillions of times in a tiny amount of time.
An idea called inflation.
It took the observable universe
and flung it apart so fast that space itself expanded faster
than the speed of light.
But could this be true
or was there a flaw in the whole idea
of the big bang itself?
There should be a telltale signature all over the sky.
An Intrepid team of scientists built
a telescope in one of the most inhospitable places on Earth
looking for the answer.
It could be one of the greatest experiments of all time.
But the team would face intense challenges
and controversy as they battle
to answer the greatest scientific mystery of them all.
So is the big bang right?
Wondering where the universe from
is the biggest question anyone can ask.
All the billions of galaxies,
the untold trillions of stars and planets stretching out
over unimaginable distances.
What could possibly have made them?
For some, the question itself was irrelevant
because the universe never had a beginning.
It had just always been.
Well our lifespans as humans are very short compared
to the age of the universe.
So during our lifetimes the universe
doesn't appear to do very much.
If you couple that with people's limited ability
to observe distant objects,
the universe did appear very static.
But for others,
a moment of creation better fitted their beliefs.
There was a persistent belief that the universe
must have been creative as we see it,
and generally that was attributed to God.
Yet, other religions believed
that the universe might be an everlasting cycle
of birth and death.
These ideas that humans have had
about whether there's a beginning to everything
or something that's more cyclical, that is everlasting,
that didn't have a beginning, that didn't have an end.
These are things that have absolutely reflected now
in the questions that we're asking
now that we actually have data and we kind of doing this
from a scientific point of view,
not a religious point of view.
Most scientists at the start
of the 20th century thought the universe was static
and had always been.
But in 1915 preconceptions about the origins
of the universe would be challenged
when Albert Einstein published a paper.
He came up with this beautiful theory
of general relativity, which tells us how the whole
of space time and should behave.
It tells us that if you put mass into it,
a bit like throwing a ball onto a rubber sheet,
it deforms space.
At its core, general relativity said
that neither space nor time are rigid,
there continuously distorted by matter.
But Einstein was troubled by the implications
of this on a cosmic scale.
He came to realize that his new theory of relativity said
that space actually should be changing.
If you just put masses into space,
the gravity of them should actually try and pull
the space between them back together
and should actually shrink space.
But Einstein hated this idea.
Einstein thought that the universe was static.
And so he came up with this thing
that he called the cosmological constant.
So Einstein's cosmological constant is a kind
of a fudge factor that he inserted into his equations.
And he did this really on just on grounds of prejudice.
You know, towering genius that he was,
he somehow felt compelled to fix his equations
to prevent the universe from expanding or contracting.
In 1922
a Soviet scientist called Alexander Friedmann
began corresponding with Einstein.
He was sort of inspired by Einstein's new theory
of relativity and tried to apply them to the whole universe.
And, you know, he quickly realized,
as Einstein had, that the natural behavior
of such a universe was to expand or contract.
And that being perfectly stable was a kind
of vanishingly, unlikely knife-edge point
between those two possibilities.
He said, depending on the kind of initial conditions,
depending on how you started things off,
space could be growing.
But whatever it is, it shouldn't be static.
It shouldn't be unchanging.
And so he wrote a couple of scientific papers,
but Einstein didn't like it.
It wasn't long
before others would challenge Einstein's position.
Working independently of Friedmann,
was mathematician and priest George Lemaitre.
Lemaitre was a very remarkable man.
He had a distinguished war career.
He was awarded the Croix de guerre by the king of Belgium
for his service in the First World War.
A few years after Friedmann, he took a step further.
He said, well, if the universe is indeed growing,
then it must have come from somewhere.
Must have had some beginning.
He called it a cosmic egg.
Lemaitre was the first to suggest
that the beginning of the universe would
also be the beginning of time.
He called the beginning of the universe,
"a day without a yesterday."
Einstein when hearing about this for the first time,
called Lemaitre's math,
"elegant, but his physics atrocious."
But Lemaitre had an ace of his sleeve.
He so figured out what we should expect
to see around us if the universe were in fact growing.
And so we should see galaxies moving away from us
and the ones that are further from our Milky Way,
should recede from us faster than the ones close by.
In a paper published in 1927,
Lemaitre had given a prediction
of how fast the expansion might be,
depending on how far away we look.
Well, this is where the experimentalist comes in
and it always pays to look
and let the universe tell us what it thinks.
And Lemaitre matter was already acquainted
with one of the world's greatest astronomers,
who was studying the most distant parts
of the visible universe.
So Edwin Hubble studied the motion of galaxies
and all the galaxies that he looked around at
were all receding from us.
And that was exactly the kind of prediction
that Lemaitre would make,
that the universe would be expanding.
In 1929 Edwin Hubble published his results
that concurred with Lemaitre's predictions,
the further away the galaxies he observed were,
the faster they were moving from us.
He calculated that the most distant galaxies
were moving away at thousands of kilometers per second.
Einstein, in fact, visited Edwin Hubble
and his telescope here in Pasadena
and came to the conclusion that putting in
this cosmological constant was a mistake
and accepted the idea that perhaps, this was possible.
The universe is actually a dynamic place,
expanding from a beginning time.
It was rapidly proposed what's going on.
It's not that there was an explosion centered on our galaxy.
It's just that the entire fabric
of space itself is expanding.
If you think of such a picture,
a kind of expanding grid
with the galaxies on the grid points,
it turns out that every point,
as it looks out to other points,
sees all the points receding.
It doesn't matter where you are,
every point is the center of the expansion as it were
and the galaxies are just being carried along in the flow
of the expansion of space.
Now that most of the world's cosmologist believed
that the universe had a definite beginning,
they could start to figure out how it might have worked.
Scientists began to develop ideas
about what should happen in these very hot conditions
in the early universe.
I think the biggest advance
was by a fellow named George Gamow.
He and his collaborators looked at the possibility
that elements were cooked up in the early universe.
And this is what's called primordial nucleosynthesis.
Gamow there that at the very beginning,
there was only intense heat and energy.
Over the next few seconds and minutes,
the energy condensed into the first atoms.
But they were incomplete atoms.
The baby universe was too hot for electrons
to become attracted to the atomic cores.
And so you have this very short window
in which you can create cores of atoms.
And you just have a long enough to do that
before the universe then cools down enough
that you can't do it.
A bit like turning your oven off.
You would only be able to develop very light elements,
like hydrogen and helium, a little bit of lithium.
And this mixture of elements was
then remarkably consistent with what astronomers can
actually see now out in the skies around us.
But Gamow and his colleagues
also made a prediction of immense importance.
He also found that as the universe expands,
it should leave a remnant radiation background.
370,000 years after the beginning,
the expanding universe would've cooled down enough
for the electrons to become attracted
to the incomplete atomic cores.
So the significance of this moment when the electrons
and protons come together, which we call recombination,
is that not only is the full hydrogen atom formed
for the first time,
but light rays now travel freely through space,
eventually towards us.
And so the prediction was that we should be bathed
in this primordial radiation of light rays
that have indeed been traveling for billions of years,
since that beginning of the universe time.
Gamow and his collaborators called
this first visible remit of creation
the cosmic microwave background.
This entire process of the universe expanding
from an ultra-dense ultra-hot state
and forging matter from energy was given its famous
and misleading name by a skeptical British cosmologist
called Fred Hoyle on a BBC radio program.
In a rather derogatory way,
he just described it as a big bang.
Well, it caught on like these things do.
When people call it the big bang,
they almost always picture the wrong thing.
They picture a firecracker at a place and a time,
what we actually observe is the infinite universe expanding
into itself with no actual first moment.
People are shocked when I tell them this.
We've been told the wrong thing by astronomers
and science writers for generations.
And it's hard to take the meaning
of the words that Fred Hoyle gave us.
If the big bang really did happen
then finding the cosmic microwave background
that Gamow and his colleagues had predicted
became a vital importance.
The challenging thing is that it would be very difficult
to find because as the universe has grown and cooled down,
this light from the early universe has stretched
its wavelength well beyond the waves that our eyes can see
into microwave wavelength.
And they should now be extremely cold, almost absolute zero.
The temperature
of this cosmic microwave background, or CMB,
was carefully predicted
by a Princeton scientist called Jim Peebles.
Some of his colleagues then set about trying to find it.
And then completely serendipitously
this wonderful thing happened.
When I took a job at Bell Labs,
they had a unique radio antenna,
which we planned to look at some special things
in radio astronomy with.
And what we found was something we weren't looking for.
Rather than collecting light,
that our eyes can see radio astronomy uses antennas
that capture light of much longer wavelengths,
like microwaves and radio waves.
Only 26 miles from Princeton University,
Robert Wilson and his colleague Arno Penzias,
wanted to use their radio antenna
to measure the emissions coming from the halo of gas
around our own galaxy.
But in order to do so,
they would first need to calibrate it.
Radio astronomers aim their big antennas
at a source they're interested in and get a signal.
But then they turn them off to the side a little bit,
and so they measure the difference between near the source
and on the source.
Wherever they pointed their telescope,
they always found background radio emission,
a kind of noisy hiss at a certain frequency.
The background should have been quite small.
And so we had a real conundrum
that the antenna was producing more noise
than we could understand.
Arno and Bob set about trying
to locate the source of the noise
that was ruining their experiment.
Yeah, we had a checklist
of something like nine different things.
But things like we had a perfect view of New York City,
could it be that the city is noisy
and that the side lobes of our antenna were picking that up?
Well, we had the perfect instrument.
We turn it around and we look at New York City, nada.
They wondered if the troublesome signals
were coming from the ground.
And so they wheeled a cart around the antenna
with the radio source in it.
But again, nothing.
Bob and Arno were narrowing down their list.
But what if it was something inside the antenna
that was causing the problems?
There was a pair of pigeons
who had taken up roost in the antenna.
They would fly up just about into the cabin of the antenna
and it must have been a nice toasty place to be.
It wasn't necessarily the pigeons
that were suspected of causing the interference,
but something they were leaving behind.
There was this white dielectric material
all over the inside of the horn reflector.
And so we thought it could be radiating.
We first got a trap and put it
where the receiver normally would be
and caught the pigeons.
We put them in a cardboard box and mailed them as far away
as we could in the company mail to a pigeon fan,
here in Whippany, New Jersey.
Well, he took a look at these pigeons,
said, "these are junk pigeons," and let them go.
Well a day or so later here are the pigeons back.
So that didn't work.
Our technician brought in a shotgun
and in the name of science dispensed with the pigeons.
In short, none of the things we could think of
and do anything about actually made any difference.
A hint at where their problems might lie,
came when Arno had a chance conversation
with the fellow astronomer.
He said to Arno,
"what's happening with your crazy experiment?"
And Arno laid it on him,
"We've got this excess noise in our antenna.
We can't find it."
He said, "You oughta talk to Bob Dicke at Princeton."
Bob Dicke was the colleague
of Jim Peebles at Princeton University,
whose team were already actively looking for evidence
of the radiation predicted by the big bang theory.
Although Peebles had calculated what kind
of radiation they were looking for,
their experiments were only being calibrated
and had yet to begin.
The team were eating lunch together when the phone rang.
Dicke picked up the phone
and they heard atmospheric radiation,
sky temperature, antennalized,
all the things they were interested in.
Dicke put down the phone and said,
"Boys, we've been scooped."
Robert Wilson and Arno Penzias
had accidentally found
what Jim Peebles and George Gamow had predicted.
We invited them over.
They looked at our antenna and all the measuring system,
and agreed that we'd done the right thing.
We went down to the conference room
and they told us about how a big bang might produce
a universe full of radiation.
Wilson, Penzias, and Peebles
were all awarded Nobel Prizes
for their parts in this momentous discovery.
And suddenly it changed everything.
The fact that we see the galaxies expanding around us.
We see the elements in the right abundances
that you'd expect from a hot big bang.
And then we see this radiation coming
from all directions in the sky.
Those three things became the pillars
of the big bang theory.
So now scientists had a picture
of a universe that expands from a big bang,
cooks up basic elements in the inferno,
and leaves behind a detectable background.
But that couldn't be the whole picture.
The hot big bang model was on pretty firm footing,
but there were definitely some puzzles.
This CMB radiation did appear indeed
to be the same temperature everywhere.
And the that's really weird
because you're receiving a ray of light
from all different directions.
And those rays of light have traveled
for 14 billion years to reach you.
And they could only have achieved the same temperature
if they were once in contact.
There was a second problem,
which is that the universe seemed
to be something known as flat.
The universe is observed to have very close
to what's known as spatial flatness.
What is spatial flatness?
So if you imagine yourself on the surface of the Earth,
the Earth, locally, looks very flat,
meaning that if you go to a sidewalk
and you draw a triangle with three straight lines to it,
you will get,
when you sum up those three angles, 180 degrees.
However, if you make that triangle bigger
and you put one vertex of the triangle in Bangkok,
one in Mexico city, and one at the South Pole,
that triangle has about 270 degrees
between its three angles when summed together.
Now imagine going off the surface of the Earth.
Pick three stars, measure the angle that they sub 10,
and make the triangle,
and observe their three interior angles and add those up.
It turns out no matter how big a triangle you make
in the universe those angles always add up to 180 degrees.
So it's very, very striking that the universe
was fine tuned to parts in a billion or a trillion
in its curvature, right after the big bang.
How could that possibly happen?
Physicists were pretty confident about their model
of how the universe worked down to a time
of about one second,
where the conditions had to be right
to start to form these light elements.
So how flat would the universe have to have been then
to explain how flat it is now?
And it has to be extremely flat to parts
in 10 to a large number.
And that seemed just very odd that that would be the case.
So the solution to both of these problems
is something called inflation.
I didn't expect that I'm going to be a cosmologist.
I thought that I'm going to work on particle physics,
but then unexpected things happen.
The original of cosmic inflation
was built independently by Alan Guth in the US
and Alexei Starobinsky in the Soviet union.
Inflation introduced a new phase at the very beginning
of the universe, before the formation of atoms
in which there was a sudden accelerated expansion
of the universe.
Inflation would've been staggeringly brief
and increased the size of the universe by a scale
that is hard to comprehend and even to say.
In much less than a trillionth of a second,
the universe would've expanded
by 100 trillion-trillion times.
And you would very rapidly blow up a space smaller
than an atom to larger than a galaxy very, very, very fast.
This means the overall universe is much bigger
than we can ever observe from our own bubble within it.
So it's a very fundamental rule in physics
that nothing can move through
the fabric of space faster than light.
But that actually says nothing
about the fabric of space itself.
The fabric of space itself can expand faster than
the speed of light in these theories.
There's nothing to prevent that.
And that's what happens during the inflationary phase.
The distance between points is growing faster
than the speed at light can close the gap
between those two points so to speak.
But there was a brief moment
before inflation began
in which the universe expanded much more slowly.
Those regions that we observe in the sky,
being the same temperature,
they were all connected at this earlier time
before the universe got ripped apart by inflation.
Inflation also explains why the universe is so flat
because that expansion takes whatever geometry universe
had prior to inflation and stretches it out tremendously.
So that local region
that we can see today looks very, very flat.
It's like, if we're on the surface of the Earth now,
we know the surface of the Earth is curved.
It has continents and oceans
and suddenly through stretching,
all we can have access to is our backyards.
Well now our backyard is going to look rather locally flat.
The original theory of cosmic inflation
utilized a core concept taken from quantum theory
that suggests that there can never be such a thing
as zero energy.
Even a random spot in the vacuum of space
has quantum particles fizzing in and out of existence.
In this picture of the big bang,
the tiny and seemingly empty spec
from which the universe would grow
was bursting with potential energy.
So this is a strange way of producing lots of particles,
lots of energy, practically from nothing.
In models for inflation,
the universe that would've been extremely compressed
was composed of like an energy field.
And it would be the stored up energy in that field
that would be released a little bit like releasing a spring.
They would have this sort of potential energy,
this energy that's raring to go.
This newly unleashed energy
and the rapid creation of space
would propel a chain reaction
of bubbles of potential energy exploding.
And as a result of it,
the universe does not look like one bubble,
but instead it looks bubbles producing bubbles,
producing bubbles, producing bubbles, forever.
It becomes a fractal.
So the classical picture of the universe,
which is hung big and round,
no, it's not a big and round.
It's something well like three
of universes growing like that.
And this mechanism,
with its random fluctuations,
is ultimately responsible for us being here at all.
So the idea of inflation is that all structure
in the universe originated from quantum fluctuations during
this hyper expansion phase at a very early time.
If the quantum fluctuation's in the big bang
were the correct description plus inflation,
then we should have roughly the pattern
of hot and cold spots that we see in a sky.
And that match with where the galaxies are today.
Sure enough, they do.
The current idea is gravity acts on the denser regions
and stops them from expanding,
pulls the material back together again to make a galaxy,
and then planets and stars.
So we're here because of those spots
in the big bang radiation,
plus gravity, which is a pretty amazing result.
But inflationary theory
in its original form had a fundamental problem.
This energy would sort of permeate space
and would be expanding incredibly fast.
And somehow you have to stop that from happening
in a gradual and smoothly controlled way.
For about a year or more,
many different people worked on it.
Steven Hawking and his collaborators wrote a paper saying
that it's impossible to solve this particular problem.
But late one night, Andrei had a brain wave.
I wake up my wife and I said,
"I think that I know how the universe was born."
During the summer of 1981,
Andrei wrote a paper on the modified theory,
which he called new inflation.
And so what Andrei Linde came up with
was a different mechanism for gently sort of rolling
into a smoother expansion
than had been come up with to begin with.
And in October, there was a conference in Moscow,
lots of brilliant people came,
and one of them was Steven Hawking.
And they gave a talk at this conference
and everybody got very excited.
But next day, I came to the talk by Steven Hawking.
Unexpectedly, they suggested me to translate.
Steve would say one word, his student say one word,
I translated this word.
It was about old inflation of the theory.
And then Steven said,
"and recently was an interesting suggestion
about how to improve it by Andrei Linde."
And I happily translated.
And next second he said,
"but this suggestion is completely wrong."
And for half an hour, I was translating why my own theory,
which I had just reported the day before,
why it does not work, et cetera, et cetera.
After the lecture, Andre asked Steven
if they could talk in more detail.
they retired to a side room where for more than two hours,
they discussed Andrei's modification to inflation.
He said something and his student would say,
"but you didn't say that before."
And this thing continued.
I ended up in his hotel.
He was showing me photographs of his family
and we became friends.
Hawking realized that Linde had solved
the issues that were plaguing inflation.
He had proposed a mechanism by which inflation
could not only start, but gracefully come to an end.
Andrei was invited to come back to Cambridge
and work with Steven where over the next year
they and their fellow cosmologist molded a simpler
and more robust inflationary theory
that became the centerpiece of big bang cosmology.
By the late 1990s cosmologists knew
that there was some evidence for inflation,
but they wanted to find the smoking gun
that would tell them that it must have happened.
And they were sure that it could be found
in patterns within the cosmic microwave background.
If inflation happens a likely thing to come from it
is this really particular signature
that we're all searching for now with our telescopes.
And it's an imprint of ripples in space time
that would've been imprinted during that inflation process.
The patterns they were looking for
are called polarization patterns.
But what is polarization?
Any given ray of light is a fluctuation
in the electric field and a fluctuation
in the magnetic field that are 90 degrees apart.
And then this whole wave train is moving
along the third direction.
As you rotate around the direction of motion,
these are other polarizations.
So you have a continuous range of polarizations
for each individual ray of light.
The polarization properties
of an individual ray of light can tell us a story
about what has happened to the light on its journey to us.
Now most of those fluctuations
we see in the microwave background,
but they're like a sound wave.
It's a compression wave traveling through the universe.
This first common type of fluctuation
creates either a cross like or circular pattern,
which is called an E-mode,
but there is another pattern called a B-mode.
And this is a one that is crucial
to finding evidence for inflation.
In Einsteins theory,
you can also have fluctuations in space time
called gravitational waves.
And they don't act like a density wave
that compresses and rarifies.
Instead they squeeze space in one direction
and stretch it in the other direction
while they're propagating in the third dimension.
Those fluctuations have a very, very specific signature.
They will have imprinted a particular form,
a particular swirliness, actually.
And if we could detect this pattern of swirling,
twisting polarization in the microwave background,
that would be perhaps indirect evidence
that inflation took place.
If it could be observed to be truly cosmological,
not caused by some systematic error in the instrument
or in the galaxy or something else,
that would be as close to
what was called smoking gun evidence
that inflation took place.
In 1996 the European Space Agency, ESA,
started planning a space mission called Planck
to map the cosmic microwave background
at very high resolution.
In the sky maps you will see the different colors show
the temperature variations.
Blues and yellows are hottest, through to greens,
and then red for the coldest areas.
Initially, we were not planning to measure polarization
when we first started out with the project.
Planck's prime mission was to do the ultimate job,
measuring the temperature variations
in the microwave background.
People had not really realized how important
and how much information polarization signals would carry.
So it was not the primary goal.
A separate project
from around the same time called Boomerang,
didn't go into space,
but used balloons to make high sensitivity observations
of the CMB.
My last year as a graduate student,
I worked on developing
new technology detectors for Boomerang.
Now the detectors that were developed on Boomerang turned
into the detectors on the Planck satellite,
and they were developed here at JPL.
In the midst of Planck's development,
the science team got more and more interested
with polarization measurement.
So I was also a postdoc
at the California Institute of Technology.
I was really fascinated by building a telescope
that was only sensitive to the polarization
of the microwave background.
Myself and Brian Keating, we came up with an approach
that would call B-modes or bust.
We proposed to the CalTech president at the time
to get some seed money.
We said, "We're going to look
for this inflationary gravitational wave signal,
to look and see if we can see it.
And build an experiment that's just tailor made
to do that one thing and do it really well."
We would've loved to take it into space,
but space born experiments will cost you anywhere
from a hundred to a thousand times more than
their ground based equivalent.
And we believed we could do it from the ground
if we went to an exquisite site like the South Pole.
Brian, Jamie, and their colleagues,
established BICEP, Background Imaging
of Cosmic Extra-Galactic Polarization.
I started working on it full-time 2007, 2008.
The stage was set for a battle
between two very different missions,
both sharing closely related technology,
But for the Planck team, they still did not really believe
that BICEP was a competitor.
Within the Planck community,
we were not really all that concerned.
What BICEP was trying to achieve was quite
a different thing, using quite a different approach.
The really novel thing about BICEP is the telescope.
So we're looking for swirly patterns in the polarization
on scales several times bigger than the full moon.
Now you don't need a very big telescope to do that.
Telescope of 25 centimeters or so would be just fine.
And actually that brings a huge number of advantages
because I can take that small telescope
and I can spin it around to take out any polarization
that's in the instrument.
It's really hard to do that with a large telescope.
The small size of the BICEP telescope
also makes it easier to cool.
The ancient light of the cosmic microwave background
is now extremely cold.
So in order to see it,
the telescope itself must be kept very cold.
I can cool that whole telescope down
to four degrees above absolute zero.
And that's very hard to do with a large telescope.
The first generation of BICEP used these kinds of detectors
we developed for Planck called a balometer.
And the basic idea is you take something that absorbs,
in this case, millimeter wave radiation,
and you stick a sensitive thermometer to that absorber.
And if any radiation hits the absorber
you measure the increase in temperature
using the thermometer.
The BICEP experiment is located
at the Amundsen-Scott South Pole Station in Antarctica.
The South Pole is flat, it's featureless, it's cold,
it's barren, it's dark.
Literally six months of the year
the sun is below the horizon and we pay one person
to sit there for the next nine months of his or her life.
But we call that person a winter-over
and we always joke, "We're gonna pay you $75,000
and all you have to do is work for one night,"
because that's all they'll be there for.
So it would sit there at the South Pole
and it would scan back and forth for years on end,
accumulating data, storing the data.
We're testing it, we're analyzing it,
we're looking for artifacts.
BICEP1 was created in 2001 and we deployed it in 2005.
It took data from 2006 till 2009.
We then decommissioned it to make way for a bigger,
better instrument called BICEP2.
Those first three years really showed
that the method worked really, really well.
Meanwhile, much of the field is struggling
with larger telescopes to do these kinds of measurements.
After 13 years of careful development,
the European Space Agency was ready
to launch the Planck spacecraft in May 2009.
I was very happy to be part of the Planck collaboration.
I joined when it was about to be launched.
So basically you can think of Planck
as a camera that has a lens
of about one and a half to two meters in diameter.
It has an array of about 50 detectors or so.
While we were pleased with the devices on Planck,
BICEP didn't have as much sensitivity
as we ultimately wanted.
We needed to increase the detectors from dozens to hundreds,
to thousands, to tens of thousands.
And the way to do that is using the same methods
that we use to make computer chips.
With a lithograph,
the entire structure and reproduce them many, many times.
And in fact, you don't wanna just reproduce the balometer,
you wanna produce everything about it,
how it couples to light, which we use a printed antenna,
and how we select the frequencies.
All this is just lithographed on the device itself.
So you build an instrument,
you measure the sky with it for a few years,
you build more detectors, more sensitivity, more data,
so you can improve the sensitivity faster.
So that's been the pattern.
There was BICEP1, then there was BICEP2,
then there was Keck Array,
but basically it's just continual arms race
of improving sensitivities.
Between 2010 and 2012,
BICEP2 collected thousands of scans of the sky.
BICEP was observing a very small part of the sky
with as much sensitivity as they could.
They chose the patch of the sky,
which they thought would be the cleanest possible.
During the same period of time,
ESA's Planck spacecraft revolved once every minute,
slowly scanning the entire cosmos over the months.
The measurements that we take,
they do not reveal things instantaneously.
The data take years to acquire.
They can take year or more to analyze.
Now we have four scientists representing
the device of two collaborations, John Kovac--
People have a slightly ivory tower view
of science sometimes.
Like we all sit in the common room,
smoking our pipes and being great chums with each other.
And science can be fiercely competitive.
People's careers depend on the results
that you publish ahead of other people.
So the theory of cosmic inflation,
which attempts to explain the start of the big bang itself,
predicts that the early universe will contain
a background of gravitational waves
that produce patterns of polarization called B-modes.
Suddenly there was an announcement
by the BICEP2 team claiming
that they have observed primordial gravitational waves.
Today were gonna be reporting the detection
of B-mode polarization as seen by the BICEP2 telescope
that matches very closely the predicted pattern.
This was big news in our community.
So many of us watched the results together.
This is amazing!
You talk about it being thrilling.
Maybe it was in a way, but it was also terrifying.
Up here today are the co-leaders
of the BICEP and Keck Array series of--
Well, I think the first reaction was "wow."
Major collaborators that you see in BICEP2
over the past--
Because it was presented as a clear cut case.
UC San Diego, Brian Heating's group there, they're--
There are considerable challenges
to separating the E-modes and the B-modes accurately enough.
We had to develop new mathematical techniques
to allow us to do that.
When we apply those techniques we started to be able
to see a B-mode detected with statistical significance
for the first time.
And this was of course tremendously exciting.
It was what we had been trying to do for all of these years.
Pattern is very distinct.
However, the signal is very small.
And they said, we have found gravitational waves.
This is yet another confirmational inflationary theory.
Everything was great.
We felt that the polarization pattern on the sky was real.
As Clem Pryke would later say,
"We instead of seeing a needle in a haystack,
we observed what was," later he called,
"a crowbar in a haystack."
Okay, so this is the actual polarization pattern map
as measured by the BICEP2 telescope.
Think of it as little sticks indicating the direction
and the magnitude of the polarization.
The most reasonable interpretation is
that it is gravity waves written
in that micro background pattern.
And those gravity waves come from the inflationary epoch
at a tiny, tiny fraction of a second after the beginning.
The BICEP team had made an announcement
that suggested that the holy grail
of signals had been found.
One that would show for certain that inflation had occurred
and that the big bang model was correct,
but there were troubles brewing.
But if other people have other data
and they can go in and say,
"actually, we don't see the same thing as you."
That's the risk you run.
As you may have gathered, if seems traditional now
that each experiment is very secretive
about what it's doing.
As soon as people started to look at the paper
and at the details, they realized that,
"maybe there are some issues here."
Now we had only measured this at one frequency,
basically where the CMB is brightest.
Now it's possible that we would have contamination
from our own galaxy from polarized dust.
The issue is that we had the means,
Planck had the means to measure the dust part of the signal.
There were no measurements available
to our team at the time of a brightness of polarized dust
in these faint regions.
the Planck satellite team had this data,
but we didn't have access to it.
The BICEP team thought
they had an agreement with ESA
that the Planck team would provide them with data
that would show the dust contribution to the BICEP signal.
But it's not the way it played out in the end.
We did ask and they did not provide us the data
that could be, A they didn't have it,
B that maybe they did have the results
and they were bluffing,
C this wasn't something that they could agree upon
on our time scale.
Well of course it was certainly not
about destroying anybody or any group,
it was about getting the good result.
Well, so the first thing that happened is
the Planck team put out a paper on the polarization
in the diffuse sky, including our region.
And it showed indeed that the polarized emission
from the galaxy was bigger than we had assumed from models.
The signal that we saw turned out to be dust emission.
The thing that clears up scientific disputes
and uncertainties is data.
In order to get a clean understanding of the problem,
you needed to use both sets of data,
you couldn't do it with Planck only,
you couldn't do it with BICEP only.
And so we very quickly decided
that we had to work together with their team.
The two teams joined forces
and together they published the results of what had happened
in this remarkable story.
They jointly told the world that BICEP
had not yet found evidence for inflation.
Well, I thought, "man, that must hurt."
That was tough luck for them.
They were too eager.
It's a bit embarrassing perhaps,
but I think being a skeptic about any result
and getting independent confirmation,
that's how science works.
And you know, point here isn't how I feel.
The point is, how do we get to the best result?
I don't think I was particularly sorry for them
in the sense they did a wonderful job.
I was sorry because it wasn't true.
Because it would've been scientifically much more exciting
to actually have access to that signal
and therefore to inflation,
and to a new part of knowledge in the universe.
It is widely acknowledged
that the BICEP team did great science,
but at this time they were fooled by the galactic dust.
They made a mistake, but on the other hand,
they were the first to come to the verge
of possible discovery and still the best.
Theoretical scientists, like Andrei,
need experimental scientists like Jamie, Brian and Clem.
A scientific theory is of limited use
unless an experimenter can come along
and prove that a theory is correct.
And this is the story of the big bang.
Edwin Hubble proved Lemaitre right,
that the universe must be expanding.
Penzias And Wilson proved that theorists were right
when they found the cosmic microwave background.
But as we shall see, finding evidence for inflation
is still the key objective.
I think the consensus today in a community is
that inflation is the best candidate for the phenomena,
the early part of the universe.
And so I think we should pursue this.
No question about it.
I'm involved in a project called the Simon's Observatory,
which is building a set of telescopes
that are going to be in the North of Chile.
So the Simon's Observatory is a large collaboration,
spanning all seven continents
of approximately 300 individual researchers
and about 45 institutions.
If you can't be in space, the two best sites are Chile
and the South Pole for looking at this CMB radiation.
It's 'cause they're very dry.
BICEP is also continuously pushing the envelope
on their experiments at the South Pole.
And both teams plan to build
a healthy competition between them.
So their goal is to compete with us head to head,
and we'll see who does the best.
The goal is to reach similar sensitivity to this radiation
and to these gravitational waves
from both of these locations on Earth.
I see it as being important
to have two complementary approaches
to such an important potential discovery.
I think it's very good that people are collaborating
and sharing information.
I think that's the way science ought to work.
Best part about it is that no one can do it alone.
One of the powerful lessons of BICEP2 is
that it will take the village of all of cosmology
that we will rely on the confirmation
of sometimes our competitors.
Looking down the horizon,
we can perhaps envision a day
where there'll just be one experiment.
So there is a concrete plan in the works
for the ultimate ground based CMB experiment,
and it's being called CMBS4.
The objective is to make observations
from both South Pole and from Chile
with apparatus somewhat similar to the current experiments,
but just a lot more of it.
And so it's kind of a mega experiment.
I'm sure that all the work that has been done so far,
including the one from BICEP,
will help in reaching that final goal.
The big bang theory attempts to answer
the biggest question anyone can ask,
"Where do we come from?"
The theory has passed many challenging tests
and it is the best description of how our universe began.
We have to be prepared that all these dedicated efforts
may ultimately fall behind of the unknowable screen.
It may be that there is simply a limit
to how much one can know about the earliest moments
of the creation of the universe.
The way I say it is you imagine in your mind,
running the universe backwards
to where everything is compressed and compressed,
and hotter and hotter and hotter,
and when you run out of imagination,
that's what you call the big bang.
And we may push the imagination a little farther,
but eventually you probably still run out of imagination.
that used to be the purview solely of theologians.
Last century, a radical idea about the origin
of everything was born.
It would become the most famous theory in all of science.
Fred Hoyle, in rather derogatory way,
described it as a big bang.
As the big bang theory evolved,
it made predictions that were only confirmed by accident.
This radiation was discovered using this radio antenna
that wasn't even looking for it.
What was coming out of this thing
had to come from somewhere.
Had science discovered the moment of creation?
We're looking at the infant pictures of the baby universe.
But the big bang theory had its challenges.
There were several problems
that could not be explained without conspiracies.
Cosmologists were forced to propose
a mind-blowing scenario to fix the difficulties.
I wake up my wife and I said,
"I think that I know how the universe was born."
They claimed that the universe expanded
by trillions of times in a tiny amount of time.
An idea called inflation.
It took the observable universe
and flung it apart so fast that space itself expanded faster
than the speed of light.
But could this be true
or was there a flaw in the whole idea
of the big bang itself?
There should be a telltale signature all over the sky.
An Intrepid team of scientists built
a telescope in one of the most inhospitable places on Earth
looking for the answer.
It could be one of the greatest experiments of all time.
But the team would face intense challenges
and controversy as they battle
to answer the greatest scientific mystery of them all.
So is the big bang right?
Wondering where the universe from
is the biggest question anyone can ask.
All the billions of galaxies,
the untold trillions of stars and planets stretching out
over unimaginable distances.
What could possibly have made them?
For some, the question itself was irrelevant
because the universe never had a beginning.
It had just always been.
Well our lifespans as humans are very short compared
to the age of the universe.
So during our lifetimes the universe
doesn't appear to do very much.
If you couple that with people's limited ability
to observe distant objects,
the universe did appear very static.
But for others,
a moment of creation better fitted their beliefs.
There was a persistent belief that the universe
must have been creative as we see it,
and generally that was attributed to God.
Yet, other religions believed
that the universe might be an everlasting cycle
of birth and death.
These ideas that humans have had
about whether there's a beginning to everything
or something that's more cyclical, that is everlasting,
that didn't have a beginning, that didn't have an end.
These are things that have absolutely reflected now
in the questions that we're asking
now that we actually have data and we kind of doing this
from a scientific point of view,
not a religious point of view.
Most scientists at the start
of the 20th century thought the universe was static
and had always been.
But in 1915 preconceptions about the origins
of the universe would be challenged
when Albert Einstein published a paper.
He came up with this beautiful theory
of general relativity, which tells us how the whole
of space time and should behave.
It tells us that if you put mass into it,
a bit like throwing a ball onto a rubber sheet,
it deforms space.
At its core, general relativity said
that neither space nor time are rigid,
there continuously distorted by matter.
But Einstein was troubled by the implications
of this on a cosmic scale.
He came to realize that his new theory of relativity said
that space actually should be changing.
If you just put masses into space,
the gravity of them should actually try and pull
the space between them back together
and should actually shrink space.
But Einstein hated this idea.
Einstein thought that the universe was static.
And so he came up with this thing
that he called the cosmological constant.
So Einstein's cosmological constant is a kind
of a fudge factor that he inserted into his equations.
And he did this really on just on grounds of prejudice.
You know, towering genius that he was,
he somehow felt compelled to fix his equations
to prevent the universe from expanding or contracting.
In 1922
a Soviet scientist called Alexander Friedmann
began corresponding with Einstein.
He was sort of inspired by Einstein's new theory
of relativity and tried to apply them to the whole universe.
And, you know, he quickly realized,
as Einstein had, that the natural behavior
of such a universe was to expand or contract.
And that being perfectly stable was a kind
of vanishingly, unlikely knife-edge point
between those two possibilities.
He said, depending on the kind of initial conditions,
depending on how you started things off,
space could be growing.
But whatever it is, it shouldn't be static.
It shouldn't be unchanging.
And so he wrote a couple of scientific papers,
but Einstein didn't like it.
It wasn't long
before others would challenge Einstein's position.
Working independently of Friedmann,
was mathematician and priest George Lemaitre.
Lemaitre was a very remarkable man.
He had a distinguished war career.
He was awarded the Croix de guerre by the king of Belgium
for his service in the First World War.
A few years after Friedmann, he took a step further.
He said, well, if the universe is indeed growing,
then it must have come from somewhere.
Must have had some beginning.
He called it a cosmic egg.
Lemaitre was the first to suggest
that the beginning of the universe would
also be the beginning of time.
He called the beginning of the universe,
"a day without a yesterday."
Einstein when hearing about this for the first time,
called Lemaitre's math,
"elegant, but his physics atrocious."
But Lemaitre had an ace of his sleeve.
He so figured out what we should expect
to see around us if the universe were in fact growing.
And so we should see galaxies moving away from us
and the ones that are further from our Milky Way,
should recede from us faster than the ones close by.
In a paper published in 1927,
Lemaitre had given a prediction
of how fast the expansion might be,
depending on how far away we look.
Well, this is where the experimentalist comes in
and it always pays to look
and let the universe tell us what it thinks.
And Lemaitre matter was already acquainted
with one of the world's greatest astronomers,
who was studying the most distant parts
of the visible universe.
So Edwin Hubble studied the motion of galaxies
and all the galaxies that he looked around at
were all receding from us.
And that was exactly the kind of prediction
that Lemaitre would make,
that the universe would be expanding.
In 1929 Edwin Hubble published his results
that concurred with Lemaitre's predictions,
the further away the galaxies he observed were,
the faster they were moving from us.
He calculated that the most distant galaxies
were moving away at thousands of kilometers per second.
Einstein, in fact, visited Edwin Hubble
and his telescope here in Pasadena
and came to the conclusion that putting in
this cosmological constant was a mistake
and accepted the idea that perhaps, this was possible.
The universe is actually a dynamic place,
expanding from a beginning time.
It was rapidly proposed what's going on.
It's not that there was an explosion centered on our galaxy.
It's just that the entire fabric
of space itself is expanding.
If you think of such a picture,
a kind of expanding grid
with the galaxies on the grid points,
it turns out that every point,
as it looks out to other points,
sees all the points receding.
It doesn't matter where you are,
every point is the center of the expansion as it were
and the galaxies are just being carried along in the flow
of the expansion of space.
Now that most of the world's cosmologist believed
that the universe had a definite beginning,
they could start to figure out how it might have worked.
Scientists began to develop ideas
about what should happen in these very hot conditions
in the early universe.
I think the biggest advance
was by a fellow named George Gamow.
He and his collaborators looked at the possibility
that elements were cooked up in the early universe.
And this is what's called primordial nucleosynthesis.
Gamow there that at the very beginning,
there was only intense heat and energy.
Over the next few seconds and minutes,
the energy condensed into the first atoms.
But they were incomplete atoms.
The baby universe was too hot for electrons
to become attracted to the atomic cores.
And so you have this very short window
in which you can create cores of atoms.
And you just have a long enough to do that
before the universe then cools down enough
that you can't do it.
A bit like turning your oven off.
You would only be able to develop very light elements,
like hydrogen and helium, a little bit of lithium.
And this mixture of elements was
then remarkably consistent with what astronomers can
actually see now out in the skies around us.
But Gamow and his colleagues
also made a prediction of immense importance.
He also found that as the universe expands,
it should leave a remnant radiation background.
370,000 years after the beginning,
the expanding universe would've cooled down enough
for the electrons to become attracted
to the incomplete atomic cores.
So the significance of this moment when the electrons
and protons come together, which we call recombination,
is that not only is the full hydrogen atom formed
for the first time,
but light rays now travel freely through space,
eventually towards us.
And so the prediction was that we should be bathed
in this primordial radiation of light rays
that have indeed been traveling for billions of years,
since that beginning of the universe time.
Gamow and his collaborators called
this first visible remit of creation
the cosmic microwave background.
This entire process of the universe expanding
from an ultra-dense ultra-hot state
and forging matter from energy was given its famous
and misleading name by a skeptical British cosmologist
called Fred Hoyle on a BBC radio program.
In a rather derogatory way,
he just described it as a big bang.
Well, it caught on like these things do.
When people call it the big bang,
they almost always picture the wrong thing.
They picture a firecracker at a place and a time,
what we actually observe is the infinite universe expanding
into itself with no actual first moment.
People are shocked when I tell them this.
We've been told the wrong thing by astronomers
and science writers for generations.
And it's hard to take the meaning
of the words that Fred Hoyle gave us.
If the big bang really did happen
then finding the cosmic microwave background
that Gamow and his colleagues had predicted
became a vital importance.
The challenging thing is that it would be very difficult
to find because as the universe has grown and cooled down,
this light from the early universe has stretched
its wavelength well beyond the waves that our eyes can see
into microwave wavelength.
And they should now be extremely cold, almost absolute zero.
The temperature
of this cosmic microwave background, or CMB,
was carefully predicted
by a Princeton scientist called Jim Peebles.
Some of his colleagues then set about trying to find it.
And then completely serendipitously
this wonderful thing happened.
When I took a job at Bell Labs,
they had a unique radio antenna,
which we planned to look at some special things
in radio astronomy with.
And what we found was something we weren't looking for.
Rather than collecting light,
that our eyes can see radio astronomy uses antennas
that capture light of much longer wavelengths,
like microwaves and radio waves.
Only 26 miles from Princeton University,
Robert Wilson and his colleague Arno Penzias,
wanted to use their radio antenna
to measure the emissions coming from the halo of gas
around our own galaxy.
But in order to do so,
they would first need to calibrate it.
Radio astronomers aim their big antennas
at a source they're interested in and get a signal.
But then they turn them off to the side a little bit,
and so they measure the difference between near the source
and on the source.
Wherever they pointed their telescope,
they always found background radio emission,
a kind of noisy hiss at a certain frequency.
The background should have been quite small.
And so we had a real conundrum
that the antenna was producing more noise
than we could understand.
Arno and Bob set about trying
to locate the source of the noise
that was ruining their experiment.
Yeah, we had a checklist
of something like nine different things.
But things like we had a perfect view of New York City,
could it be that the city is noisy
and that the side lobes of our antenna were picking that up?
Well, we had the perfect instrument.
We turn it around and we look at New York City, nada.
They wondered if the troublesome signals
were coming from the ground.
And so they wheeled a cart around the antenna
with the radio source in it.
But again, nothing.
Bob and Arno were narrowing down their list.
But what if it was something inside the antenna
that was causing the problems?
There was a pair of pigeons
who had taken up roost in the antenna.
They would fly up just about into the cabin of the antenna
and it must have been a nice toasty place to be.
It wasn't necessarily the pigeons
that were suspected of causing the interference,
but something they were leaving behind.
There was this white dielectric material
all over the inside of the horn reflector.
And so we thought it could be radiating.
We first got a trap and put it
where the receiver normally would be
and caught the pigeons.
We put them in a cardboard box and mailed them as far away
as we could in the company mail to a pigeon fan,
here in Whippany, New Jersey.
Well, he took a look at these pigeons,
said, "these are junk pigeons," and let them go.
Well a day or so later here are the pigeons back.
So that didn't work.
Our technician brought in a shotgun
and in the name of science dispensed with the pigeons.
In short, none of the things we could think of
and do anything about actually made any difference.
A hint at where their problems might lie,
came when Arno had a chance conversation
with the fellow astronomer.
He said to Arno,
"what's happening with your crazy experiment?"
And Arno laid it on him,
"We've got this excess noise in our antenna.
We can't find it."
He said, "You oughta talk to Bob Dicke at Princeton."
Bob Dicke was the colleague
of Jim Peebles at Princeton University,
whose team were already actively looking for evidence
of the radiation predicted by the big bang theory.
Although Peebles had calculated what kind
of radiation they were looking for,
their experiments were only being calibrated
and had yet to begin.
The team were eating lunch together when the phone rang.
Dicke picked up the phone
and they heard atmospheric radiation,
sky temperature, antennalized,
all the things they were interested in.
Dicke put down the phone and said,
"Boys, we've been scooped."
Robert Wilson and Arno Penzias
had accidentally found
what Jim Peebles and George Gamow had predicted.
We invited them over.
They looked at our antenna and all the measuring system,
and agreed that we'd done the right thing.
We went down to the conference room
and they told us about how a big bang might produce
a universe full of radiation.
Wilson, Penzias, and Peebles
were all awarded Nobel Prizes
for their parts in this momentous discovery.
And suddenly it changed everything.
The fact that we see the galaxies expanding around us.
We see the elements in the right abundances
that you'd expect from a hot big bang.
And then we see this radiation coming
from all directions in the sky.
Those three things became the pillars
of the big bang theory.
So now scientists had a picture
of a universe that expands from a big bang,
cooks up basic elements in the inferno,
and leaves behind a detectable background.
But that couldn't be the whole picture.
The hot big bang model was on pretty firm footing,
but there were definitely some puzzles.
This CMB radiation did appear indeed
to be the same temperature everywhere.
And the that's really weird
because you're receiving a ray of light
from all different directions.
And those rays of light have traveled
for 14 billion years to reach you.
And they could only have achieved the same temperature
if they were once in contact.
There was a second problem,
which is that the universe seemed
to be something known as flat.
The universe is observed to have very close
to what's known as spatial flatness.
What is spatial flatness?
So if you imagine yourself on the surface of the Earth,
the Earth, locally, looks very flat,
meaning that if you go to a sidewalk
and you draw a triangle with three straight lines to it,
you will get,
when you sum up those three angles, 180 degrees.
However, if you make that triangle bigger
and you put one vertex of the triangle in Bangkok,
one in Mexico city, and one at the South Pole,
that triangle has about 270 degrees
between its three angles when summed together.
Now imagine going off the surface of the Earth.
Pick three stars, measure the angle that they sub 10,
and make the triangle,
and observe their three interior angles and add those up.
It turns out no matter how big a triangle you make
in the universe those angles always add up to 180 degrees.
So it's very, very striking that the universe
was fine tuned to parts in a billion or a trillion
in its curvature, right after the big bang.
How could that possibly happen?
Physicists were pretty confident about their model
of how the universe worked down to a time
of about one second,
where the conditions had to be right
to start to form these light elements.
So how flat would the universe have to have been then
to explain how flat it is now?
And it has to be extremely flat to parts
in 10 to a large number.
And that seemed just very odd that that would be the case.
So the solution to both of these problems
is something called inflation.
I didn't expect that I'm going to be a cosmologist.
I thought that I'm going to work on particle physics,
but then unexpected things happen.
The original of cosmic inflation
was built independently by Alan Guth in the US
and Alexei Starobinsky in the Soviet union.
Inflation introduced a new phase at the very beginning
of the universe, before the formation of atoms
in which there was a sudden accelerated expansion
of the universe.
Inflation would've been staggeringly brief
and increased the size of the universe by a scale
that is hard to comprehend and even to say.
In much less than a trillionth of a second,
the universe would've expanded
by 100 trillion-trillion times.
And you would very rapidly blow up a space smaller
than an atom to larger than a galaxy very, very, very fast.
This means the overall universe is much bigger
than we can ever observe from our own bubble within it.
So it's a very fundamental rule in physics
that nothing can move through
the fabric of space faster than light.
But that actually says nothing
about the fabric of space itself.
The fabric of space itself can expand faster than
the speed of light in these theories.
There's nothing to prevent that.
And that's what happens during the inflationary phase.
The distance between points is growing faster
than the speed at light can close the gap
between those two points so to speak.
But there was a brief moment
before inflation began
in which the universe expanded much more slowly.
Those regions that we observe in the sky,
being the same temperature,
they were all connected at this earlier time
before the universe got ripped apart by inflation.
Inflation also explains why the universe is so flat
because that expansion takes whatever geometry universe
had prior to inflation and stretches it out tremendously.
So that local region
that we can see today looks very, very flat.
It's like, if we're on the surface of the Earth now,
we know the surface of the Earth is curved.
It has continents and oceans
and suddenly through stretching,
all we can have access to is our backyards.
Well now our backyard is going to look rather locally flat.
The original theory of cosmic inflation
utilized a core concept taken from quantum theory
that suggests that there can never be such a thing
as zero energy.
Even a random spot in the vacuum of space
has quantum particles fizzing in and out of existence.
In this picture of the big bang,
the tiny and seemingly empty spec
from which the universe would grow
was bursting with potential energy.
So this is a strange way of producing lots of particles,
lots of energy, practically from nothing.
In models for inflation,
the universe that would've been extremely compressed
was composed of like an energy field.
And it would be the stored up energy in that field
that would be released a little bit like releasing a spring.
They would have this sort of potential energy,
this energy that's raring to go.
This newly unleashed energy
and the rapid creation of space
would propel a chain reaction
of bubbles of potential energy exploding.
And as a result of it,
the universe does not look like one bubble,
but instead it looks bubbles producing bubbles,
producing bubbles, producing bubbles, forever.
It becomes a fractal.
So the classical picture of the universe,
which is hung big and round,
no, it's not a big and round.
It's something well like three
of universes growing like that.
And this mechanism,
with its random fluctuations,
is ultimately responsible for us being here at all.
So the idea of inflation is that all structure
in the universe originated from quantum fluctuations during
this hyper expansion phase at a very early time.
If the quantum fluctuation's in the big bang
were the correct description plus inflation,
then we should have roughly the pattern
of hot and cold spots that we see in a sky.
And that match with where the galaxies are today.
Sure enough, they do.
The current idea is gravity acts on the denser regions
and stops them from expanding,
pulls the material back together again to make a galaxy,
and then planets and stars.
So we're here because of those spots
in the big bang radiation,
plus gravity, which is a pretty amazing result.
But inflationary theory
in its original form had a fundamental problem.
This energy would sort of permeate space
and would be expanding incredibly fast.
And somehow you have to stop that from happening
in a gradual and smoothly controlled way.
For about a year or more,
many different people worked on it.
Steven Hawking and his collaborators wrote a paper saying
that it's impossible to solve this particular problem.
But late one night, Andrei had a brain wave.
I wake up my wife and I said,
"I think that I know how the universe was born."
During the summer of 1981,
Andrei wrote a paper on the modified theory,
which he called new inflation.
And so what Andrei Linde came up with
was a different mechanism for gently sort of rolling
into a smoother expansion
than had been come up with to begin with.
And in October, there was a conference in Moscow,
lots of brilliant people came,
and one of them was Steven Hawking.
And they gave a talk at this conference
and everybody got very excited.
But next day, I came to the talk by Steven Hawking.
Unexpectedly, they suggested me to translate.
Steve would say one word, his student say one word,
I translated this word.
It was about old inflation of the theory.
And then Steven said,
"and recently was an interesting suggestion
about how to improve it by Andrei Linde."
And I happily translated.
And next second he said,
"but this suggestion is completely wrong."
And for half an hour, I was translating why my own theory,
which I had just reported the day before,
why it does not work, et cetera, et cetera.
After the lecture, Andre asked Steven
if they could talk in more detail.
they retired to a side room where for more than two hours,
they discussed Andrei's modification to inflation.
He said something and his student would say,
"but you didn't say that before."
And this thing continued.
I ended up in his hotel.
He was showing me photographs of his family
and we became friends.
Hawking realized that Linde had solved
the issues that were plaguing inflation.
He had proposed a mechanism by which inflation
could not only start, but gracefully come to an end.
Andrei was invited to come back to Cambridge
and work with Steven where over the next year
they and their fellow cosmologist molded a simpler
and more robust inflationary theory
that became the centerpiece of big bang cosmology.
By the late 1990s cosmologists knew
that there was some evidence for inflation,
but they wanted to find the smoking gun
that would tell them that it must have happened.
And they were sure that it could be found
in patterns within the cosmic microwave background.
If inflation happens a likely thing to come from it
is this really particular signature
that we're all searching for now with our telescopes.
And it's an imprint of ripples in space time
that would've been imprinted during that inflation process.
The patterns they were looking for
are called polarization patterns.
But what is polarization?
Any given ray of light is a fluctuation
in the electric field and a fluctuation
in the magnetic field that are 90 degrees apart.
And then this whole wave train is moving
along the third direction.
As you rotate around the direction of motion,
these are other polarizations.
So you have a continuous range of polarizations
for each individual ray of light.
The polarization properties
of an individual ray of light can tell us a story
about what has happened to the light on its journey to us.
Now most of those fluctuations
we see in the microwave background,
but they're like a sound wave.
It's a compression wave traveling through the universe.
This first common type of fluctuation
creates either a cross like or circular pattern,
which is called an E-mode,
but there is another pattern called a B-mode.
And this is a one that is crucial
to finding evidence for inflation.
In Einsteins theory,
you can also have fluctuations in space time
called gravitational waves.
And they don't act like a density wave
that compresses and rarifies.
Instead they squeeze space in one direction
and stretch it in the other direction
while they're propagating in the third dimension.
Those fluctuations have a very, very specific signature.
They will have imprinted a particular form,
a particular swirliness, actually.
And if we could detect this pattern of swirling,
twisting polarization in the microwave background,
that would be perhaps indirect evidence
that inflation took place.
If it could be observed to be truly cosmological,
not caused by some systematic error in the instrument
or in the galaxy or something else,
that would be as close to
what was called smoking gun evidence
that inflation took place.
In 1996 the European Space Agency, ESA,
started planning a space mission called Planck
to map the cosmic microwave background
at very high resolution.
In the sky maps you will see the different colors show
the temperature variations.
Blues and yellows are hottest, through to greens,
and then red for the coldest areas.
Initially, we were not planning to measure polarization
when we first started out with the project.
Planck's prime mission was to do the ultimate job,
measuring the temperature variations
in the microwave background.
People had not really realized how important
and how much information polarization signals would carry.
So it was not the primary goal.
A separate project
from around the same time called Boomerang,
didn't go into space,
but used balloons to make high sensitivity observations
of the CMB.
My last year as a graduate student,
I worked on developing
new technology detectors for Boomerang.
Now the detectors that were developed on Boomerang turned
into the detectors on the Planck satellite,
and they were developed here at JPL.
In the midst of Planck's development,
the science team got more and more interested
with polarization measurement.
So I was also a postdoc
at the California Institute of Technology.
I was really fascinated by building a telescope
that was only sensitive to the polarization
of the microwave background.
Myself and Brian Keating, we came up with an approach
that would call B-modes or bust.
We proposed to the CalTech president at the time
to get some seed money.
We said, "We're going to look
for this inflationary gravitational wave signal,
to look and see if we can see it.
And build an experiment that's just tailor made
to do that one thing and do it really well."
We would've loved to take it into space,
but space born experiments will cost you anywhere
from a hundred to a thousand times more than
their ground based equivalent.
And we believed we could do it from the ground
if we went to an exquisite site like the South Pole.
Brian, Jamie, and their colleagues,
established BICEP, Background Imaging
of Cosmic Extra-Galactic Polarization.
I started working on it full-time 2007, 2008.
The stage was set for a battle
between two very different missions,
both sharing closely related technology,
But for the Planck team, they still did not really believe
that BICEP was a competitor.
Within the Planck community,
we were not really all that concerned.
What BICEP was trying to achieve was quite
a different thing, using quite a different approach.
The really novel thing about BICEP is the telescope.
So we're looking for swirly patterns in the polarization
on scales several times bigger than the full moon.
Now you don't need a very big telescope to do that.
Telescope of 25 centimeters or so would be just fine.
And actually that brings a huge number of advantages
because I can take that small telescope
and I can spin it around to take out any polarization
that's in the instrument.
It's really hard to do that with a large telescope.
The small size of the BICEP telescope
also makes it easier to cool.
The ancient light of the cosmic microwave background
is now extremely cold.
So in order to see it,
the telescope itself must be kept very cold.
I can cool that whole telescope down
to four degrees above absolute zero.
And that's very hard to do with a large telescope.
The first generation of BICEP used these kinds of detectors
we developed for Planck called a balometer.
And the basic idea is you take something that absorbs,
in this case, millimeter wave radiation,
and you stick a sensitive thermometer to that absorber.
And if any radiation hits the absorber
you measure the increase in temperature
using the thermometer.
The BICEP experiment is located
at the Amundsen-Scott South Pole Station in Antarctica.
The South Pole is flat, it's featureless, it's cold,
it's barren, it's dark.
Literally six months of the year
the sun is below the horizon and we pay one person
to sit there for the next nine months of his or her life.
But we call that person a winter-over
and we always joke, "We're gonna pay you $75,000
and all you have to do is work for one night,"
because that's all they'll be there for.
So it would sit there at the South Pole
and it would scan back and forth for years on end,
accumulating data, storing the data.
We're testing it, we're analyzing it,
we're looking for artifacts.
BICEP1 was created in 2001 and we deployed it in 2005.
It took data from 2006 till 2009.
We then decommissioned it to make way for a bigger,
better instrument called BICEP2.
Those first three years really showed
that the method worked really, really well.
Meanwhile, much of the field is struggling
with larger telescopes to do these kinds of measurements.
After 13 years of careful development,
the European Space Agency was ready
to launch the Planck spacecraft in May 2009.
I was very happy to be part of the Planck collaboration.
I joined when it was about to be launched.
So basically you can think of Planck
as a camera that has a lens
of about one and a half to two meters in diameter.
It has an array of about 50 detectors or so.
While we were pleased with the devices on Planck,
BICEP didn't have as much sensitivity
as we ultimately wanted.
We needed to increase the detectors from dozens to hundreds,
to thousands, to tens of thousands.
And the way to do that is using the same methods
that we use to make computer chips.
With a lithograph,
the entire structure and reproduce them many, many times.
And in fact, you don't wanna just reproduce the balometer,
you wanna produce everything about it,
how it couples to light, which we use a printed antenna,
and how we select the frequencies.
All this is just lithographed on the device itself.
So you build an instrument,
you measure the sky with it for a few years,
you build more detectors, more sensitivity, more data,
so you can improve the sensitivity faster.
So that's been the pattern.
There was BICEP1, then there was BICEP2,
then there was Keck Array,
but basically it's just continual arms race
of improving sensitivities.
Between 2010 and 2012,
BICEP2 collected thousands of scans of the sky.
BICEP was observing a very small part of the sky
with as much sensitivity as they could.
They chose the patch of the sky,
which they thought would be the cleanest possible.
During the same period of time,
ESA's Planck spacecraft revolved once every minute,
slowly scanning the entire cosmos over the months.
The measurements that we take,
they do not reveal things instantaneously.
The data take years to acquire.
They can take year or more to analyze.
Now we have four scientists representing
the device of two collaborations, John Kovac--
People have a slightly ivory tower view
of science sometimes.
Like we all sit in the common room,
smoking our pipes and being great chums with each other.
And science can be fiercely competitive.
People's careers depend on the results
that you publish ahead of other people.
So the theory of cosmic inflation,
which attempts to explain the start of the big bang itself,
predicts that the early universe will contain
a background of gravitational waves
that produce patterns of polarization called B-modes.
Suddenly there was an announcement
by the BICEP2 team claiming
that they have observed primordial gravitational waves.
Today were gonna be reporting the detection
of B-mode polarization as seen by the BICEP2 telescope
that matches very closely the predicted pattern.
This was big news in our community.
So many of us watched the results together.
This is amazing!
You talk about it being thrilling.
Maybe it was in a way, but it was also terrifying.
Up here today are the co-leaders
of the BICEP and Keck Array series of--
Well, I think the first reaction was "wow."
Major collaborators that you see in BICEP2
over the past--
Because it was presented as a clear cut case.
UC San Diego, Brian Heating's group there, they're--
There are considerable challenges
to separating the E-modes and the B-modes accurately enough.
We had to develop new mathematical techniques
to allow us to do that.
When we apply those techniques we started to be able
to see a B-mode detected with statistical significance
for the first time.
And this was of course tremendously exciting.
It was what we had been trying to do for all of these years.
Pattern is very distinct.
However, the signal is very small.
And they said, we have found gravitational waves.
This is yet another confirmational inflationary theory.
Everything was great.
We felt that the polarization pattern on the sky was real.
As Clem Pryke would later say,
"We instead of seeing a needle in a haystack,
we observed what was," later he called,
"a crowbar in a haystack."
Okay, so this is the actual polarization pattern map
as measured by the BICEP2 telescope.
Think of it as little sticks indicating the direction
and the magnitude of the polarization.
The most reasonable interpretation is
that it is gravity waves written
in that micro background pattern.
And those gravity waves come from the inflationary epoch
at a tiny, tiny fraction of a second after the beginning.
The BICEP team had made an announcement
that suggested that the holy grail
of signals had been found.
One that would show for certain that inflation had occurred
and that the big bang model was correct,
but there were troubles brewing.
But if other people have other data
and they can go in and say,
"actually, we don't see the same thing as you."
That's the risk you run.
As you may have gathered, if seems traditional now
that each experiment is very secretive
about what it's doing.
As soon as people started to look at the paper
and at the details, they realized that,
"maybe there are some issues here."
Now we had only measured this at one frequency,
basically where the CMB is brightest.
Now it's possible that we would have contamination
from our own galaxy from polarized dust.
The issue is that we had the means,
Planck had the means to measure the dust part of the signal.
There were no measurements available
to our team at the time of a brightness of polarized dust
in these faint regions.
the Planck satellite team had this data,
but we didn't have access to it.
The BICEP team thought
they had an agreement with ESA
that the Planck team would provide them with data
that would show the dust contribution to the BICEP signal.
But it's not the way it played out in the end.
We did ask and they did not provide us the data
that could be, A they didn't have it,
B that maybe they did have the results
and they were bluffing,
C this wasn't something that they could agree upon
on our time scale.
Well of course it was certainly not
about destroying anybody or any group,
it was about getting the good result.
Well, so the first thing that happened is
the Planck team put out a paper on the polarization
in the diffuse sky, including our region.
And it showed indeed that the polarized emission
from the galaxy was bigger than we had assumed from models.
The signal that we saw turned out to be dust emission.
The thing that clears up scientific disputes
and uncertainties is data.
In order to get a clean understanding of the problem,
you needed to use both sets of data,
you couldn't do it with Planck only,
you couldn't do it with BICEP only.
And so we very quickly decided
that we had to work together with their team.
The two teams joined forces
and together they published the results of what had happened
in this remarkable story.
They jointly told the world that BICEP
had not yet found evidence for inflation.
Well, I thought, "man, that must hurt."
That was tough luck for them.
They were too eager.
It's a bit embarrassing perhaps,
but I think being a skeptic about any result
and getting independent confirmation,
that's how science works.
And you know, point here isn't how I feel.
The point is, how do we get to the best result?
I don't think I was particularly sorry for them
in the sense they did a wonderful job.
I was sorry because it wasn't true.
Because it would've been scientifically much more exciting
to actually have access to that signal
and therefore to inflation,
and to a new part of knowledge in the universe.
It is widely acknowledged
that the BICEP team did great science,
but at this time they were fooled by the galactic dust.
They made a mistake, but on the other hand,
they were the first to come to the verge
of possible discovery and still the best.
Theoretical scientists, like Andrei,
need experimental scientists like Jamie, Brian and Clem.
A scientific theory is of limited use
unless an experimenter can come along
and prove that a theory is correct.
And this is the story of the big bang.
Edwin Hubble proved Lemaitre right,
that the universe must be expanding.
Penzias And Wilson proved that theorists were right
when they found the cosmic microwave background.
But as we shall see, finding evidence for inflation
is still the key objective.
I think the consensus today in a community is
that inflation is the best candidate for the phenomena,
the early part of the universe.
And so I think we should pursue this.
No question about it.
I'm involved in a project called the Simon's Observatory,
which is building a set of telescopes
that are going to be in the North of Chile.
So the Simon's Observatory is a large collaboration,
spanning all seven continents
of approximately 300 individual researchers
and about 45 institutions.
If you can't be in space, the two best sites are Chile
and the South Pole for looking at this CMB radiation.
It's 'cause they're very dry.
BICEP is also continuously pushing the envelope
on their experiments at the South Pole.
And both teams plan to build
a healthy competition between them.
So their goal is to compete with us head to head,
and we'll see who does the best.
The goal is to reach similar sensitivity to this radiation
and to these gravitational waves
from both of these locations on Earth.
I see it as being important
to have two complementary approaches
to such an important potential discovery.
I think it's very good that people are collaborating
and sharing information.
I think that's the way science ought to work.
Best part about it is that no one can do it alone.
One of the powerful lessons of BICEP2 is
that it will take the village of all of cosmology
that we will rely on the confirmation
of sometimes our competitors.
Looking down the horizon,
we can perhaps envision a day
where there'll just be one experiment.
So there is a concrete plan in the works
for the ultimate ground based CMB experiment,
and it's being called CMBS4.
The objective is to make observations
from both South Pole and from Chile
with apparatus somewhat similar to the current experiments,
but just a lot more of it.
And so it's kind of a mega experiment.
I'm sure that all the work that has been done so far,
including the one from BICEP,
will help in reaching that final goal.
The big bang theory attempts to answer
the biggest question anyone can ask,
"Where do we come from?"
The theory has passed many challenging tests
and it is the best description of how our universe began.
We have to be prepared that all these dedicated efforts
may ultimately fall behind of the unknowable screen.
It may be that there is simply a limit
to how much one can know about the earliest moments
of the creation of the universe.
The way I say it is you imagine in your mind,
running the universe backwards
to where everything is compressed and compressed,
and hotter and hotter and hotter,
and when you run out of imagination,
that's what you call the big bang.
And we may push the imagination a little farther,
but eventually you probably still run out of imagination.