Freeman: Our Universe.
It's awe-inspiring and baffling.
From colossal explosions of stars
to the strange movements of tiny particles...
...each new discovery
seems to reveal another layer of mystery.
Our understanding of the world around us
has taken us from the Stone Age to the Silicon Age.
Now ironclad laws of physics are breaking apart.
What we believe is reality may not be real at all.
The future of humanity depends on our discovering...
...how the Universe really works.
Space, time, life itself.
The secrets of the cosmos lie Through the Wormhole.
Think of existence
as an enormous web that we're all woven into,
but we can't see the whole thing.
We just see the patch where we are standing.
We can't see the whole of reality.
But what if we could see it all?
What if we could understand
how the whole of creation joins together?
The rewards of finding this equation would be enormous,
a revolution in science
far beyond anything that has come before -
a great leap forward
that will transform life on Earth
and ensure our survival as a species.
But what hope do we mere mortals have
of uncovering the hidden secrets of the Universe,
of knowing the mind of God?
I remember my first day of school,
the day I was supposed to start learning about the world
and how it works.
I made it about 20 yards to the schoolhouse,
then I froze.
What hope did I have
of understanding everything or anything?
My mind reeled.
I ran back home.
I wonder if scientists feel much the same way.
There is so much we don't know
about why the Universe functions the way it does.
Imagine trying to play a game of chess
if you don't know the rules.
You might figure out some moves,
but a lot of it would make no sense.
Once you know the rules, though,
you can begin to move the pieces with purpose.
Science is our means to discover those rules,
and so far we've revealed quite a few of them.
But what if we've got them wrong?
Deep in the basement tunnels of Purdue University,
scientists Jere Jenkins and Ephraim Fischbach
have discovered
that one of the supposedly unbreakable laws of physics
is broken.
It began with a mystery.
Man: I'll come out and set up a few tethers
and receive some tools,
then he'll come out right after me.
Jenkins: The second week of December of 2006,
astronauts from the space shuttle
were up in the International Space Station,
and everybody was out on an E.V.A.,
and there was a solar storm.
Because the astronauts were all out there,
the solar storm was big news.
Sitting there and watching that news story, I thought,
"Wow, wouldn't that be funny
if I saw that appear in the data?"
Freeman: Jenkins studies
a powerful source of energy we can't see
but is all around us -
radioactivity.
Every second of every day,
the Sun sprays out showers of radioactive atoms.
These atoms are unstable.
They spit out energy until they burn away
in a process known as radioactive decay.
Radioactive decay is supposed to be a random process
that cannot be affected by anything.
Jenkins: In early December of 2006,
we're plotting this.
It's a nice, straight line.
It's following exactly like it should,
but then on December 13th, a flare happened.
And we see that the decay has actually departed
what the standard decay line should have been,
and it departed it for quite some time.
This is actually the space of about four days.
It appeared, or so it seemed,
that something may have been changing
this radioactive-decay process,
which nothing is supposed to change.
Freeman: Fischbach, a theoretical physicist,
struggled with the huge implications of this finding.
Knowing how fast radioactive particles break down
is critical for nuclear power,
weapons, electronics, and medicine.
Could it be that a concept so uniformly accepted
and central to modern life was wrong?
The idea that nuclear decays
cannot be influenced by an external influence
is so fundamental to so many aspects of quantum physics,
nuclear physics, elementary-particle physics,
that changing that would likely have a significant change
on our understanding of the Universe,
as well as on practical applications.
Freeman: Still reeling from this shock,
Jenkins and Fischbach uncovered another mystery.
Radioactive decay was not just being affected
by the solar flare.
The discharge of radioactive particles appears to change
depending on how close the Earth is to the Sun.
Fischbach: When the Earth is closer to the Sun,
around January 4th,
the rate of radioactive decay seems to be faster.
And when farther away, the rate seems to be slower.
Now, we can illustrate this in the following way.
I represent the Sun,
and Jere is gonna represent the Earth,
and the bucket represents
a sample of radioactive radium atoms.
And you'll see that as Jere moves in an ellipse,
where he's closer to the Earth around January 4th,
more tennis balls are thrown out,
meaning more particles come out than happen around July 4th.
Freeman: This small change in numbers
could have big consequences.
Cancer patients receive very tiny doses of radiation
to kill their rebel cells.
If the strength of that radiation changes seasonally,
they might get too little or too much of a dose.
Knowing the difference could save lives.
But the duo's most important discovery
could secure the future of the human race.
40 hours prior to the actual time of the flare,
we saw the decay rate change and actually leave the line.
After the flare,
it started to recover and move back toward the line.
So, this possibly gives us the opportunity, then,
to predict when these solar flares are happening.
Freeman: A large solar flare could wipe out
every one of the nearly 3,000 satellites orbiting the Earth.
In a flash, we would lose the Internet,
GPS, television, radio, telephones,
and the systems that control our power grids.
Knowing a flare is coming could avert a global apocalypse.
If this phenomenon is real, as we believe it is,
then it's essential to understand how this is happening
because this will certainly be
a part of a bigger puzzle that we must understand
to put all this physics together.
Freeman: We're groping in the dark of the vast Universe,
thinking we have uncovered its deepest truths,
then finding we still have much to learn
about the rules of nature.
And nature does not make things easy for us.
Down at the smallest scale of existence,
deep in the weird world of quantum mechanics,
it seems to play by two different rules
at the same time.
And the deeper we probe into its mysteries,
the more we are forced to ask not just how the Universe works,
but whether anything is real.
Quantum mechanics has transformed the world.
We owe most of our amazing technology
to its explanations of how extremely small particles...
behave.
But we don't really understand it.
In the quantum world, nothing seems to make sense.
Reality stops being... real.
This mystery is our greatest obstacle
to unlocking the secrets of the Universe.
If we can solve it,
we may hold the keys to creation itself.
Vienna, Austria,
is arguably the birthplace of quantum mechanics.
This is where you will find
the leading quantum experimentalist in the world,
professor Anton Zeilinger.
Zeilinger: When I first heard of quantum mechanics
when I was a student,
I was immediately struck by three things -
first, its unbelievable mathematical beauty.
Secondly, by the incredible precision
to which the predictions work.
And thirdly,
by the fact that... it doesn't make sense.
Freeman: Quantum mechanics describes the behavior
of all the tiny particles that everything is made of.
This knowledge has given us computers,
nuclear power, satellites, advanced medicine -
most of the great leaps forward
humanity has taken in the past 100 years.
But the quantum world seems to run contrary
to everything we know about the laws of nature.
Simply put, down where things are very, very small,
the Universe follows a different set of rules.
Consider the phenomenon of quantum nonlocality,
when two tiny particles instantly share information
across vast distances.
If there were quantum dice,
it would mean that if I throw one die here,
it shows a certain number.
The other dice thrown at some distant location
would show the same number.
How can that be?
Quantum mechanics describes it very well.
Freeman: Time and again Zeilinger has proven
that no matter how extreme its predictions,
quantum theory works even though it shouldn't.
And perhaps the ultimate proof
of just how unsettling quantum mechanics can be
is something called the double-slit experiment.
It will make you question whether reality exists at all.
This simple configuration
shoots particles of light called photons
one at a time through two tiny slits in a screen.
Zeilinger: There's a laser which produces light.
This light is attenuated
such that only one photon at a time emerges.
These photons pass through a two-slit assembly,
and then we have a camera which registers the pattern
behind the two-slit assembly.
So, what we see is that the photons arrive
one by one on the screen - some here, some there -
and it looks pretty random.
Freeman: Since the photons travel one by one -
some through this slit, some through that slit -
you would expect them to leave
a pattern of two stripes on the wall,
and you would be wrong.
They mysteriously create a band of stripes.
This is what you would expect to see
if a constant beam of light shined through the two slits.
It would spread across the wall like a wave.
So, how can single bullet-like particles of light
create a wave pattern?
This could only happen
if the particles go through both slits at the same time.
In other words,
the particle is in two places at once.
But strangest of all is what happens
when you put detectors next to the slits.
When the photons are being watched,
the wave pattern disappears.
Take away the detectors, and the wave pattern comes back.
This suggests that we can change the way reality behaves
just by looking at it.
Does this mean that reality itself
is not real?
The modern answer is that the path taken by the photon
is not an element of reality.
We are not allowed to talk about
the photon passing through this or this slit.
Neither are we allowed to say
that the photons pass through both slits.
All this kind of language is not applicable.
Freeman: So, do we just keep reaping the benefits
from quantum mechanics
and accept that, deep down, nature plays by a set of rules
that will forever remain a mystery?
Zeilinger: The interesting message here is
that we have quantum physics now around for nearly 100 years,
and we are still working at the foundations.
And that tells me that when we find it,
it will be an absolute revelation.
It will be something different from what we have been thinking.
If the quantum theorists are correct,
we will never understand
the fundamental level of the Universe.
Our hopes of finding an ultimate theory will fail,
and the human race
will hit a roadblock it can't break through.
But what if they're wrong?
What if the truth about what happens
deep inside you, me,
and everything else in the Universe
is there if we're willing to look for it?
For most of the 20th century,
scientists believed quantum physics could not be explained,
that we would just have to accept
that we'll never know why things behave as they do
down at the deepest levels of existence.
But now a growing band of rebel scientists thinks
there may be a logical explanation
for quantum weirdness after all
and new hope for revealing
the ultimate truth of our Universe.
The trail begins here...
with a drop of silicon.
In his Paris laboratory,
physicist Yves Couder and his team
conduct an amazing series of experiments.
They are observing the behavior of silicon droplets
bouncing in lockstep on a vibrating plate.
Couder: The liquid of the drop
never touches the liquid of the substrate.
So, they're always separated by a film.
And, in fact, it is stable.
You can keep the drop bouncing on the liquid surface
for several days if you wish.
Freeman: Using a camera that shoots 1,000 frames per second,
Couder has discovered that these droplets
mimic behavior seen in the quantum world.
And that shouldn't be possible,
because the quantum world and the large-scale world
play by two different sets of rules.
Yet here we see a single droplet moving randomly
like a quantum particle,
but behaving like a quantum wave.
If you watch this carefully, you'll notice that the wave
appears to be guiding the droplet.
In fact, the wave fields around the droplets
develop a memory of the trails they have followed.
Despite their random behavior,
they follow a small number of paths.
Again, this is eerily similar
to the behavior of quantum objects.
This runs so contrary to popular belief
that, at first, Couder refused to believe what he was seeing.
Couder: In any physics experiment,
you only see what you are prepared to see.
Of course, it was very obvious that there was a memory,
but it took us some time to realize
that it was that that we were observing,
because you have to adapt to this new idea.
Freeman: Perhaps most revealing of all,
Couder has reproduced the double-slit experiment
using his bouncing silicon droplets.
The mystery of quantum mechanics is,
how can things like electrons
sometimes behave like particles and sometimes behave like waves?
Perhaps this is the answer.
They are particles and waves.
Of course, this system, though small, is not quantum.
Couder: Our system is not a model of quantum mechanics,
but is an association of a particle and a wave.
And some of its properties are similar
to the properties that are observed in quantum mechanics.
Freeman: Couder won't claim that his experiments show us
what is really happening
down at the deepest layers of existence.
But this man will.
To him, those droplets are more proof
that the quantum world makes sense after all
and that reality really exists.
Antony Valentini of Clemson University
is a quantum heretic.
He loudly proclaims
that physics went off the rails in the 1920s
when it embraced the doctrine of quantum uncertainty,
which says that nothing is real until we look at it.
Valentini champions the theory that got left behind.
It was created by one of the pillars
of early 20th-century physics,
Louis De Broglie.
Valentini: Louis De Broglie's original idea is
an electron is both a wave and a particle all the time.
It's not the case that, well, sometimes it's a particle,
sometimes it's a wave.
There is a wave guiding a particle at all times.
And De Broglie called this a pilot wave.
Freeman: In quantum theory,
there's something called the probability wave,
a purely mathematical object that tells you the chance
of finding an electron at any point in space.
Pilot wave theory
treats this wave as a real physical object.
Valentini: So, a simple analog is a bottle.
Someone is on an island, and they want to send a message.
So they write something on a piece of paper,
put it in a bottle, close it, and throw it in the ocean.
And water waves simply push the bottle along.
Freeman: There is a crucial difference
between the waves we know and the pilot wave.
According to the theory,
pilot waves exist in hidden dimensions of space
beyond the three we know.
If true, this means that,
contrary to the accepted theory in physics,
quantum objects obey the same rules as large objects.
They do not exist in two places at once.
They're part of the real world.
Valentini: I think that quantum mechanics itself
is not even a candidate
for the truth about the microscopic world,
because it simply doesn't attempt to describe
precisely what the microscopic world is.
The mere fact that there are different theories
about what the answer might be
doesn't mean that there's no answer.
And eventually one of them is found to be the correct one.
Freeman: To understand how the Universe works,
we need to unlock
why the quantum world is so different
from the world we know.
It is an unsolved mystery
that affects every single person on Earth,
and this man thinks he can solve it.
The more we understand the inner workings of the Universe,
the more we humans are rewarded with new medicines,
new technologies,
and undreamed of improvements in our lives.
But some say we're a long way off
from unlocking the Universe's deepest secrets.
We want definitive answers.
What we have are mysteries upon mysteries.
And one of the greatest mysteries
is how the big stuff
and the small stuff in the Universe fit together.
Two well-tested theories describe how matter behaves -
relativity theory,
which governs the physics of the large,
and quantum theory, which describes the very small.
If they were a couple, relativity would be a logical,
pocket-protector-wearing engineer
who strictly follows the speed limit of light.
Quantum theory would be his volatile artist wife
who seems to be everywhere at once.
On paper, they don't get along.
But in the real world, they are a happy pair.
And like some real-life odd couples,
no one understands why.
The mystery boils down to gravity.
Gravity dominates the world we know,
and thanks to Newton and Einstein,
we understand it pretty well.
But physicists have no idea what role gravity plays
in the quantum realm
or its effect on space and time.
If we crack this mystery,
we will finally know if it is possible
to travel back in time or through a wormhole.
Petr Horava has a history of exploring
the wild frontier of physics.
Now he's tackling quantum gravity.
Horava: So, how do you reconcile quantum mechanics and gravity?
There are several different ways it can happen.
Either quantum mechanics is stronger and wins
and gravity has to be modified,
or quantum mechanics has to be modified
and gravity stays the same as in Einstein's general relativity.
Freeman: Petr feels the key is
to watch how things change in scale
between the upper layers of nature,
where gravity holds sway,
and the quantum layers down below.
Nature organizes itself in layers of structure,
and you see more and more layers as you zoom in
and gain a better resolution of how you view the system.
It's one of the most important theoretical concepts
in modern physics.
Freeman: To Petr, nature is an archaeological dig
that we're slowly excavating layer by layer.
Right now, we're only capable of uncovering a small part
of the vast and complex ultimate truth.
But we can learn a lot
by comparing the layers we can see.
In this picture, the two images of Mona Lisa
represent the two faces of space-time -
space and time.
They look the same
when we look at it at large scales,
but perhaps when we zoom in
and look at the system at much smaller scales,
it could be that space and time scale
in a very different way.
This could be the missing piece of the puzzle
of quantum gravity.
Freeman: Petr suspects that as you shrink down
to the smallest and deepest level of existence,
space begins to stretch at a different rate from time
until they tear apart.
Think of space-time as analogous to this sheet of paper.
At microscopic scales,
it's smooth and geometric, two-dimensional.
But if you tear the piece of paper into two halves
and look at the edge of the paper -
zoom in, zoom out -
the structure is similar to itself,
but only if you stretch in the horizontal direction
with a different rate
than when you stretch with a vertical direction.
Freeman: From a distance, the tear looks smooth.
But close up,
you can see mountains and valleys along the edge.
Similarly, space and time seem perfectly joined
from a distance.
But close up, you can see the separation.
Petr thinks this tearing apart of time and space
at the microscopic scale is precisely why
the strange rules of quantum mechanics emerge.
If space and time are unhinged,
particles can't be in a specific place at a specific time.
Hence, fuzziness and uncertainty.
Unraveling the enigma of quantum gravity
is a major hurdle in our quest
to understand how the Universe works.
But it shrinks against the magnitude
of the biggest mystery facing humanity.
95% of the Universe is missing.
This woman may know where and what it is.
The more we peel away the layers of nature,
the more we realize that something is missing -
something big.
An enormous chunk of the Universe
seems to be invisible.
We can't see it, hear it, or detect it in any way.
But if we want to unlock the secrets of the Universe,
if we want to advance as a species,
we have to find out what and where it is.
The Universe began with the Big Bang,
a shattering explosion of raw energy.
That energy burst outward in a mass of superheated plasma.
As it cooled, it began to clump together
into all the material in the Universe -
the solids, liquids, and gases that everything is made of.
To crack the cosmic code that underlies our Universe,
we have to understand energy in all its forms.
But what if almost 95% of the Universe
is made of a form of energy we can't see
and don't understand?
These are the kinds of questions
confronted daily in Geneva, Switzerland,
the home of the world's largest particle accelerator -
the Large Hadron Collider -
and also hundreds of physicists.
Clare Burrage is one of them, but she's hardly typical.
Young, female, and an accomplished figure skater,
Clare is trying to solve the vast mystery
of the missing Universe.
Burrage: So, if we think about the Sun,
the light from the Sun carries energy to us here on Earth,
and we can feel the warmth of the Sun on our skin
on a nice day.
But Einstein tells us that what's happening is
that energy and mass are the same thing.
So, in the center of the Sun,
mass is being turned into energy,
and that's what's transmitted by the light
here to us on Earth.
So, the energy from the Sun
we know and we understand very well,
but it seems like there's another form of energy
out there in the Universe called dark energy
that we don't understand at all.
Freeman: Accepted laws of physics dictate
that the expansion of the Universe after the Big Bang
should be slowing down.
But recent astronomical observations have revealed
that the expansion is rapidly speeding up.
Some unexplained form of energy is pushing galaxies apart.
Burrage: So, at the moment,
I'm moving forward even though I'm not doing anything
because of the force of gravity.
But if I were in space,
where there are no forces acting on me,
I shouldn't be moving at all.
If I'm moving forwards,
then there has to be something very strange acting on me,
and this is what we call dark energy.
Freeman: How much of the Universe is dark energy?
Put it this way.
Here's the Universe.
This sliver, 4.6%, is all the matter we can see.
Near-massless particles called neutrinos
take up another 0.4%.
We think that something called dark matter
accounts for another 23%.
Dark energy is the remaining 72%
of the mass and energy of the Universe.
We cannot see it, touch it, taste it, or detect it,
but cosmologists are certain it is there.
Without dark energy,
gravity would cause the Universe to collapse in on itself.
Clare suspects that dark energy is a by-product
of a radical new piece of physics,
an undiscovered particle called the chameleon.
These mysterious particles
actually carry an entirely different basic force
than the four that physicists know about,
a fifth fundamental force.
Burrage: In physics as we understand it,
there are four forces.
So, they are gravity, which holds us here on Earth.
There are the electric interactions between atoms
and the strong and weak forces
that control what happens in atoms.
And so if there is something new,
a new particle like the chameleon,
like dark energy,
it's going to look to us like there's a fifth force out there.
This force carrier is called a chameleon
because it can change its appearance.
When it is heavy,
it becomes sluggish and ineffective.
When it is light,
it can zip around much faster and become stronger.
How heavy it is depends on its environment -
how much stuff is around it.
Burrage: So, here on Earth, there's a lot of stuff around,
a lot of matter,
and the chameleon becomes very heavy, very massive.
It doesn't interact with the things around it very much,
and that's why we don't see it in our everyday lives
and in experiments here on Earth.
But in intergalactic space, where there's almost nothing,
the chameleon becomes very, very light,
and it can interact with things over huge distances.
And that's why it can drive the acceleration
of the expansion of the Universe.
Freeman: This shape-shifting property
explains why the chameleon has yet to be spotted
in our particle accelerators.
It should be everywhere -
inside you and me and far out in the cosmos.
But how do we detect a master of disguise?
Burrage: The chameleon shows up in experiments
on really tiny scales and on really huge scales.
So you can look for it
in the ways that particles behave in colliders
on really tiny scales.
But also,
it affects the way that light travels,
and so we can look on very large scales
at how light from stars comes to us
and whether we can see
the effects of the chameleon there.
Freeman: Our slow and steady understanding
of electromagnetism and the nuclear forces
has transformed our lives,
from electricity to telecommunications,
transportation to warfare.
What benefits could dark energy bring us?
It's very hard to say now
how a better understanding of dark energy
is going to make people's lives better.
But in the past, understanding things better
has always led to benefits for mankind.
So, in some ways, understanding dark energy,
for understanding the Universe, it's more important
than understanding the physics that we know here on Earth.
The particles that we understand
make up about a percent of the Universe as we know it.
Dark energy is a massively more important contribution.
Freeman: Dark energy is the unknown variable
in our quest to crack the cosmic code...
to find a set of equations
that describe how the Universe really works.
But this man says that doesn't go far enough.
He believes equations don't just describe the Universe.
Equations are the Universe,
and we are all living inside them.
We are hunting for an ultimate equation,
the theory of everything
that will explain the mechanisms of the Universe
and revolutionize life on Earth.
One man believes that equation exists
and the solution is the Universe.
According to him,
the equation of everything is everywhere you look,
and we are all part of it.
Max Tegmark lives in Winchester, Massachusetts,
a northern suburb of Boston.
He's an outdoorsy sort
who likes to go on long walks and think.
But Tegmark's thoughts are a bit more exotic
than your average power walker's ponderings.
Tegmark: I think the reason
our Universe is so well-described by math
is that it is math, in the sense that we are living
in a giant mathematical structure.
So, the reason we physicists have discovered
all of these equations which describe our world so well
is simply because these equations
can approximately describe
the true math which is our reality.
Freeman: To Tegmark,
equations are windows on the Universe,
and the Universe is pure math.
Tegmark: At first glance,
our Universe doesn't seem mathematical at all.
We don't have big numbers written visibly in the sky.
But if we look more closely,
we find mathematical patterns and shapes all around us.
Like, if I mess around with my garden hose here...
the water makes this very simple shape called a parabola,
which has this extremely simple mathematical equation,
"Y" equals "X" squared.
This mathematical shape, the parabola,
is really built into nature at quite a fundamental level
because it describes the motion with gravity
of any object, regardless of what it's made of.
When we look around us in the Universe,
we see shapes everywhere.
We see that all the planets are going around the Sun
in a shape called an ellipse.
It just looks like the stretched circle.
And anything orbiting anything out there in the Universe,
why is it always that shape?
You know, not a figure eight or a square?
As soon as we scratch beneath the surface,
we start to discover all these patterns and regularities
and even numbers.
Like, if I just pick up some sticks here,
and I ask, like, how many sticks can I put here
which are perpendicular to each other?
I get a number. I get three.
We have a fancy number for this in physics.
We call it the dimensionality of space.
And these numbers that are built into nature are very important,
because if you tweak them a little bit,
if you say the proton isn't
1,836 times heavier than an electron,
but 5,000 times heavier, for instance, we would die.
In fact, if you change many of the numbers
by just a few percent,
the Sun might blow up or suddenly atoms would collapse
and life as we know it just wouldn't be possible.
So, not only are these numbers there,
but they're extremely important
for understanding the very essence of our reality.
Freeman: This brings us back to an uncomfortable notion
suggested by the prevailing theory of quantum mechanics.
At the deepest level of reality,
nothing is solid.
There is only information -
numbers adhering to a set of rules
we don't yet understand.
Tegmark: The only properties an electron has
is a bunch of numbers.
We physicists have names for them like spin and charge,
but they're really just numbers.
There's really nothing there at the bottom level
except numbers, except math.
Freeman: Math may be the ultimate truth,
but given our limitations
and how vast and strange so much of nature seems to be,
is it even possible to solve this problem?
Can we ever know how the Universe really works?
There's certainly no guarantee
that we'll find the ultimate equation,
but I think we do have a shot at it.
It's really remarkable how far we've come as a species
in the last 100 years,
beyond our wildest dreams in understanding stuff.
And there's no better way to guarantee we're gonna fail
than to not try.
If I'm wrong
and there is something inherently nonmathematical
about the Universe,
then physics is ultimately doomed.
We're gonna reach a roadblock
beyond which you just can't proceed.
Whereas, if I'm right,
that would actually be a very happy situation
where there is no roadblock
and our progress would only be limited by our own imagination.
Will we ever see the entire web of reality?
Can we find, and will we understand,
the ultimate truth?
Right now, we are like archaeologists
who have uncovered a small triangle buried in the sand,
the tip of an enormous pyramid that we can't yet see.
Perhaps it's presumptuous
for human beings to think we ever will.
But we continue to uncover the truth,
bit by bit, piece by piece.
If we keep digging,
we may finally reveal the full beauty of creation...
and perhaps steal a glimpse into the mind of God.