Through the Wormhole s05e09 Episode Script

Is There A Shadow Universe?

There's something hiding in the shadows - a type of matter we can't see or touch but is all around us.
Scientists agree it has shaped our universe, but they have no idea what it is or what form it takes.
Could this mysterious matter have produced stars and planets of its own? And could this dark cosmos, one day, come crashing into ours? Is there a shadow universe? Space, time, life itself The secrets of the cosmos lie through the wormhole.
Through The Wormhole S05E09 IS THERE A SHADOW UNIVERSE? We live in a universe filled with light.
At least that's what it looks like when we gaze into the sky.
But scientists are now sure there is far more matter in this universe than we can see.
We know this dark matter must exist because we can detect the pull of its gravity.
What's going on in this hidden world? Could it have formed its own dark stars, planets, and maybe even life-forms? And could this shadow universe pose a threat to our world of light? On summer nights, my friends and I used to play with sparklers.
Their flickering lights were so bright in the darkness, everything around them seemed to disappear.
It was easy to forget their every move was controlled by an invisible hand.
An invisible hand also guides the movement of our universe.
Astronomers are sure a vast cosmic ocean of unseeable matter is pulling stars off their expected courses.
Discovering the true nature of this unknown matter has become the most pressing question in cosmology, perhaps in all of physics.
Experimental physicist, Raphael Lang, from Purdue university, is one of many scientists trying to capture and study dark matter.
We really know all this dark matter exists.
We have no clue what it's made out of.
But we know it's there, and that's what I'm trying to do.
I'm trying to find out what is it made out of.
It's a huge challenge because we only feel the feeble pull of dark matter's gravity.
Its particles pass right through the matter that we are made of.
So it's a bit like trying to catch a fish with your hands.
So you can try to catch fish with your hands, and, well, that - that's not going to work.
The fish is just - just way too fast and too slippery.
You're never going to catch a fish with your hands.
So you need different tools.
To catch dark matter, Raphael needs something that can interact with it directly.
The one thing we do know is that dark matter has mass.
The particles we know get their mass from the Higgs boson.
If you can interact with the Higgs boson, then you have mass.
Higgs boson particles create an invisible force field that fills the universe.
We believe everything in our universe gets mass by interacting with this Higgs field.
So isn't it natural to think that maybe the dark matter gets its mass also from the Higgs boson? If that's the case, that would be great, because maybe then we can talk to the dark matter through the Higgs boson channel.
If dark matter does get its mass from the Higgs bosons, Raphael may be able to use them as tools to interact with dark matter, and it would also make his fishing trip a little easier.
Maybe the Higgs boson can act as a tool, like a fishing rod, that helps us to catch the dark matter.
So at one end we are and we talk to the Higgs boson, and the Higgs boson, the other end, talks to the dark matter.
But as any good fisherman knows, just because you have the right tools doesn't mean you're guaranteed to catch a fish.
Raphael is working on an underground detector in italy called xenon 100.
It uses a large vat filled with 100 kilos of ultra-pure and highly inert liquid xenon.
Liquid xenon is very dense.
So the atomic nuclei - they're really densely packed, which is great because it gives the dark matter a lot of stuff to interact with.
So let's take some dark matter and let's drop it in the liquid xenon, and let's see what happens.
As it falls in, it will go through most of the liquid xenon without interacting, but maybe we are lucky, and one of the xenon atoms - it kicks the nucleus.
That xenon nucleus races out of the tank at high speed, leaving a trail of light in its wake.
We don't really observe the dark matter itself.
What we do is we observe the nucleus flying through the xenon.
The team at the xenon 100 detector has been running the experiment since 2008.
So far, it has not seen any sign of dark matter.
But Raphael believes an improved bigger detector, the xenon 1 ton, has a good chance of grasping this elusive particle.
So xenon 1 ton will be than anything that we have today.
What that means is that we can do something that would take us a whole year to wait and catch those particles.
We can do that in a couple of days.
If Raphael is correct, we may soon have our first glimpse of dark matter.
But there might be another way for us to find it - not by catching dark matter, but by creating it.
John butterworth is a leading experimental physicist at the University college London and at the L.
In Geneva.
This colossal machine famously created the Higgs boson in 2012.
It has also created every other particle of matter that we know to exist.
Together, they make up the standard model of particles.
The standard model is our best understanding of what we call fundamental particles, and that is stuff that everything else in the universe is made of.
But when I said that everything in the universe is made up of these fundamental particles, the big exception is dark matter probably isn't, as far as we can tell.
Particle physicists like John, however, have one idea for what these dark matter particles might be, but it's an idea that requires you to spin reality on its head.
I'm on the london eye, and it's a good place to talk about angular momentum.
Angular momentum is - is what you get when you multiply the speed of something that's going round with the distance to the axle that it's going around.
Fundamental particles also have angular momentum, which physicists call spin.
There are two types of particles, matter particles, all the tangible stuff in the universe, and force particles that carry pure energy.
These two types spin at different rates.
Imagine John is a particle, and he's spinning around the london eye.
If he's a forced particle, he'll spin at one rate.
If he's a matter particle, he'll have only half that spin.
But some physicists think all the particles of force and matter may have hidden counterparts that spin differently.
So, given that all the force carriers have got spin one, and all the matter particles have got spin half, it's quite a natural question to ask, "what if I swap them over? What if I made all the force carriers have to spin half?" These differently spinning versions of force particles would, in fact, be matter.
The photon would have a matter version called the photino.
The force particle John would have a matter particle called johnino.
So you would get a lot of these produced in the big bang.
They would hang around in the universe, but they'd do nothing else, and that's essentially the description of dark matter.
That's what dark matter does.
John has been scouring the mini big bangs created by the L.
, Looking for matter versions of forced particles like the photino.
But John is beginning to worry because so far he's seen nothing.
We've not found any direct evidence for these other half of the particles.
Now, there's still a chance, but there's a lot less chance, I would say, than there used to be.
We can never hope to discover a shadow universe until we have dark matter in our hands.
But this physicist thinks he's on the cusp of snagging it, thanks to its cosmic dance partner.
To people who believe in the supernatural, ghosts are evidence of a larger world of spirits beyond our senses.
A few decades ago, physicists discovered particles that seemed like ghosts.
They move right through solid matter.
They call them neutrinos.
Neutrinos could be the key to discovering a larger world of ghostly particles making up a shadow universe.
Brazilian-born physicist Andr� de Gouv�a has spent most of his career studying neutrinos.
Neutrinos look a lot like the dark matter in - in the sense that they interact very, very weakly.
Now it turns out that over the years, we learned enough about the neutrinos to know for sure that the neutrinos are not all of the dark matter because they're too light.
Cosmologists have calculated how much dark mass there must be in the universe, and they are sure that neutrinos can only account for a very small percentage of it.
But there's something strange about the neutrino - the way it spins.
And Andr� thinks that could mean it has a hidden cosmic dance partner - a partner that may account for the remaining mass of dark matter.
All particles have an intrinsic property called spin.
Now for the matter particles that we know about, the spin comes in two types.
We refer to that - those two types - as handedness.
So some particles are referred to as left-handed, other particles are referred to as right-handed.
So this is illustrated by the dancers in the back.
Scientists believe the big bang filled the early universe with equal numbers of right and left-handed particles.
All of them danced separately and had no mass, but then, a split second later, the Higgs boson kicked into action.
It partnered up left and right-handed particles, and in doing so, gave the pair mass.
Now, when the Higgs boson comes along, uh, the Higgs boson allows them to talk to each other, and it allows them to pair up, and once they start talking to one another, uh, they behave as one particle with mass.
This is how particles like electrons and quarks got mass, but neutrinos don't appear to be like those other particles.
Every neutrino detected so far had been left-handed.
They samba alone.
How, then, does the neutrino get its mass? What we see behind us is a left-handed neutrino.
Now, what's interesting is that we've never seen a right-handed manifestation of the neutrino, but because we know that now the neutrinos do have a mass, it indicates for us that the neutrino must have a right-handed partner.
Somewhere outside the reach of our detectors, there should be a right-handed neutrino that is pairing up with the left-handed neutrino to give it mass.
Could this undiscovered particle be dark matter? They are, as far as we can tell right now, hypothetical particles.
But it's possible that this right-handed neutrino's a dark matter.
They're very, very weakly interacting.
They're a lot less interacting than the regular neutrinos, and that's kind of what the dark matter is.
It's some very, very weakly interacting thing that we haven't seen yet that was produced early on in the universe, and then it sticks around.
The right-handed neutrino would be too elusive to be detected in current underground dark matter searches.
However, andr� believes there might be another way to find it - by looking up.
Right-handed neutrinos are not completely stable.
Like radioactive elements, they sometimes fall apart, and as they do, they create a flash of X-ray light.
A very important feature about right-handed neutrinos, is that they came to X-rays.
So one way to look for right-handed neutrinos as dark matter is to look at a region of the sky, and we see if these galaxies are emitting X-rays.
In fact, recent studies of distant galaxies have detected some strange anomalies in the X-rays they emit.
These anomalies might signal the border between the world of light and the shadows.
What's happening in that darkness? Some astronomers believe they have found evidence of a complex shadow universe where ghostly substances coalesce all around us, even inside us.
But they may have oversimplified how dark matter behaves.
Perhaps this shadow universe is made of more complicated material.
Before will dawson became an astrophysicist, he was an offshore structural engineer, but he decided to take off his gloves and hard hat to follow his passion for dark matter.
It was a decision that has him jumping for joy.
Will is one of the lucky scientists who has seen dark matter's telltale fingerprints, its gravitational effects.
So one of the major challenges that we face is how exactly do you measure where dark matter is if you can't see it? It doesn't emit light.
So what we use is a technique called gravitational lensing, and the basic principle behind this is that under a normal circumstance, a flat space-time, light always travels in straight lines.
However, when you introduce a mass to this space-time, this space-time gets curved and distorted, and light actually follows the curvature of that space.
This gravitational distortion of light by mass allows astronomers like will to find the position of giant cosmic clouds of dark matter.
They look for double images of more distant galaxies whose light is being bent around either side of the clouds.
Two particular clouds of dark matter caught will's attention.
The clouds were part of the bullet cluster, a collision of two galaxy clusters a few billion light-years from earth.
Each galaxy cluster is composed of hundreds or thousands of galaxies.
When these two cosmic giants collided the galaxies themselves moved right past one another because they were millions of light-years apart.
But the diffuse clouds of hydrogen and helium gas surrounding the galaxies barreled right into one another.
The force of electromagnetism caused their atoms to explode into a bullet-shaped inferno, but the dark matter clouds were unfazed by all this.
They sailed right through one another.
They didn't feel the powerful force of electromagnetism that regular matter feels, only the incredibly weak force of gravity.
Will wondered why such a huge portion of our universe would be so oblivious to what is happening all around it.
Is dark matter really just dumb matter? We know that it interacts via gravity, and now the question is, is dark matter more interesting than that? Is the dark universe much more complex than it is at first sight? Will formed a collaboration to find out if the accepted interpretation of the bullet cluster collision oversimplified what dark matter does.
Is this the cluster that has the dark matter in the middle or no? Uh, it has dark matter in middle, but it's not the same thing that the group is looking at many more colliding galaxy clusters.
They want to see if dark matter always passes right through itself and stays lined up with its original galaxies.
And so what we're trying to do is measure whether there's an offset between the galaxies and the dark matter.
If we observe an offset, then that's clear evidence that dark matter is interacting with itself.
There was one galaxy cluster that had their attention.
It was like the bullet cluster but older and slower.
So they called it the musket ball.
The musket ball cluster is much further progressed in its merger phase.
The bullet cluster you almost see right after the two clusters have passed through one another, whereas the musket ball cluster has had more time to separate.
Just as a plate of italian food has sauce, meatballs, and pasta, a galaxy cluster has gas galaxies and dark matter.
And just as theoretical disagreements over a meal can get heated, ingredients in a galaxy cluster have a tendency to get a little messy.
A galaxy cluster is a lot like our food fight we just had.
Not only are these galaxy clusters mergers very messy, but the galaxies - there's just so much space in between them.
They're a lot like the meatballs that - that just pass right on through.
The gas, however, is a lot like the sauce, which, whenever we threw it, a lot of it collided and got stuck in the middle.
And the dark matter - it's a little bit like the pasta that we were dealing with, where most of the pasta misses one another.
But if you look closely enough, some of the dark matter is interacting, and it might slow down a little bit with respect to the rest of it.
When dark matter meets dark matter in the musket ball, will's team found that some force beyond gravity appears to be at play.
If they can find more examples to support this idea, they may be knocking on the door of the shadow universe.
If we see the same type of offset in these other mergers that we've observed in the musket ball cluster, it provides clear evidence that dark matter is self-interacting during the merger, which would then mean that there is some new dark sector force.
Theoretical cosmologist james bullock is trying to help will understand what dark matter is up to.
He is simulating what galaxy cluster collisions should look like with different types and strengths of forces between dark matter particles.
The main thing that I'm trying to do is interpret the kind of observations that - that will makes.
So for example, we can set up a system of colliding galaxy clusters that are zooming towards each other, and we can run the simulation one time where we turn the dark matter interactions off completely.
And then, we can run it again, except this time, we dial the dark matter self-interaction up and see what happens.
And the question is, which one does the universe look like? James' simulations are showing that dark matter must interact with itself, otherwise our universe would look very different than it does.
If dark matter can interact with itself, could it have formed into solid objects? Perhaps a parallel version of the stars, planets, and universe that we know? What if those objects are out there, floating invisibly in the darkness on a collision course with our planet? When you look at your reflection, you see yourself, but it's not quite the same.
Your nose looks shifted.
Your eyes appear unbalanced.
Some physicists believe the big bang created particles in mirror-image pairs.
But those reflections became so distorted that they're barely recognizable.
Those mirror particles could be dark matter.
What would happen if you and your reflection made contact? Robert foot from the university of melbourne thinks dark matter has already come hurtling into our world.
He believes we may have already experienced it blasting its way into earth's atmosphere and that giant lumps of dark matter could be buried beneath the surface of our planet.
Robert's suspicion is based on the idea that the universe is supposed to be symmetrical.
It's something that's easily explained in a gentlemanly game of lawn bowling.
Whether I bowl with my right hand or whether I bowl with my left hand the effect is the same.
When robert accelerates the bowls, the physical force he exerts has the same effect no matter which hand he uses.
The same is mostly true when left and right-handed particles interact with the fundamental forces of nature.
When a left-handed and a right-handed particle feel the electromagnetic force, they react the same way.
The same is true for the strong force which binds the nuclei of atoms together.
Regardless of the particles' handedness, the forces should affect it the same way.
But there is one force that doesn't obey the left, right symmetry - the force that causes radioactive decay - the weak force.
With weak interactions, if I bowl with my left hand, the ball hits the target.
If I bowl with my right hand, the ball goes right through the target.
Robert thinks this anomaly could be a vital clue to understanding dark matter.
In order to restore the symmetry of the universe, we need to take a hard look in the mirror.
I'm looking in the mirror.
I'm almost symmetrical, but I'm not quite.
Problem is, my watch - it's on my left hand.
In the mirror, it's on my right hand.
Robert is like the weak force, forever stuck with a watch on his left hand, but he has found a way to fix this asymmetry - by introducing another version of himself.
Imagine if I had a twin, and this watch is not on the left hand but was on the right hand.
Robert thinks elementary particles could work the same way.
To make the universe truly symmetrical, robert and his colleagues believe there must be a mirror image of the weak force, and it must act on mirror image particles called mirror matter.
Every particle has a twin particle.
Just like ordinary particles couple with their left-handed spins, mirror particles will couple with right-handed spins.
Mirror matter particles would be stable and completely invisible to us, just like dark matter.
So, if they exist, robert and his colleagues think they could be dark matter, but their existence would also have much larger implications.
It would mean that everything in our universe is mirrored in a realm we can't see.
So, in principle, you could have mirror star formation, mirror supernova, and basically everything that happens with ordinary matter can, in principle, happen with mirror matter.
Mirror planets, stars, and galaxies may occupy the same space as regular matter inside our universe, but these mirror structures would be invisible to us.
They would pass right through the matter that we know.
Without any obvious means of interacting with the shadow realm, how will we ever know if robert is correct? The proof of his theory may have already come crashing towards earth in the form of a mirror matter asteroid.
When the solar system formed, there was a much more spread out bunch of particles, and if it captured enough mirror matter, then they could form asteroids, and they could be there in our solar system today, and occasionally they might strike earth and lead to all sorts of fascinating impacted things.
If a mirror matter asteroid only responds to the force of gravity, it would pass through the surface of the planet without our even knowing it.
But robert believes there is one way that mirror matter and regular matter can interact.
As mirror photon from the asteroid rub up against ordinary photon on earth, the two particles can create friction.
That friction would generate enough heat to turn the asteroid into a fireball and gradually slow it down.
Eventually, the asteroid would come to a stop inside the earth.
This could actually stop the asteroid in the earth, and all the energy will be released, but over a longer distance.
So it - it may not leave a crater, but it can still release the energy.
So it might melt the ground.
In 1932, explorers found some very strange melted glass lying on the top layer of sand dunes in the desert of libya.
They looked like they had been melted by the fiery impact of an asteroid, but there's no crater to be found.
Could this be a sign of a rare mirror matter asteroid crashing into earth? There's no crater.
There's no obvious impact event there, but it's a great mystery, and this is - seems one explanation.
Mirror matter and mirror asteroids might sound like science fiction, but robert contends they are no stranger than accepting an asymmetric universe.
But if the shadow universe is headed toward us, we'll need to know where it's hiding.
This physicist is taking a shot at making a map of dark matter.
She's designing the most sensitive detector ever dreamed of.
The first seafaring explorers set off into the vast oceans with no idea when they would make landfall again.
Today, we can map our globe to the centimeter, revealing where we are and even the slow tectonic movements of continents.
Our maps tell us the history of our planet and help us predict the future.
So how can we understand the shadow universe without a map of dark matter? University of michigan professor of physics katie freese thinks it's about time that we made that map.
To do this, we need to build a device to take a picture of dark matter.
I'm sitting here in a giant camera obscura.
We're looking at light coming to us from the sun outside as it passes through the trees, and then, it's captured in a pinhole and redirected onto the screen.
What we can do here with the camera obscura is also learn about the direction that the light came from.
All dark matter hunting devices to date have been simple detectors.
They can't tell the particle's trajectories.
Katie is planning to build a device that will trace the incoming paths of dark matter so she can map where they're coming from.
Her dark matter camera has a whole new kind of lens - d.
We start with quadrillions of d.
Strands attached to a thin plate of gold.
Then when the dark matter particle comes along, it strikes the gold plate.
Then, your dark matter particle would knock a gold atom forward into hanging strands of d.
Katie's detector is part physics, part biology, and the method it uses to find dark matter's path is a form of forensics.
We built a model of our dark matter detector with the d.
, And it has three parts.
We have the hanging strands of d.
We have the gold projectile, the atoms that have traveled through the d.
, And Iam the dark matter.
Just like an aimed gun propels a gold pellet on a precise path, when a dark matter particle flying in from outer space strikes a gold atom, it will send it flying forward along the same trajectory.
As the speeding gold atom tears through the quadrillions of d.
Strands, it sends cleanly cut fragments of d.
To the floor.
Well, that was fun, and it worked perfectly.
The gold projectile came in here, and we can see that it broke the d.
Strands as it moved through.
So now what we can do is take those broken d.
Strands and analyze 'em.
For each one of these strands, we know the order of the d.
Nucleotides - the a, g, c, and so on.
So we can figure out exactly where this segment of d.
Was broken.
As katie analyzes hundreds of broken d.
Strands, she is able to reconstruct the path of the gold atom, and thus, the original path of the dark matter particle.
Is the perfect material for this kind of experiment.
The accuracy you can get using d.
Is a thousand times better than anything that we've ever had before.
Over time, countless dark matter particles will propel countless gold atoms, each cutting a unique path through the d.
From those paths, katie can slowly build up a picture of where the dark matter particles are coming from.
Going backwards, we can figure out the angle that the gold bullet came in through.
So we know where all the dark matter is and where it's coming from, what it's doing physicists are getting closer to detecting dark matter and to knowing the shape of the shadow universe.
But could this shadow itself have a shadow? We and the shadow universe could both be controlled by an even darker entity - one that exists beyond the edge of creation.
Space probes have now revealed how our universe looked right after the big bang.
They show matter and dark matter spread around equally in all directions, but look a little closer, and there appears to be a crack in the sky - a line that suggests one side of the universe is different from the other.
Is there something bigger out there beyond what we can see? A shadow that molds our universe and controls everything we know? Dragan Huterer is a cosmologist at Ann Arbor, Michigan.
He was one of the first to notice this wrinkle in the universal echo of the big bang, called the cosmic microwave background.
Cosmic microwave background is the radiation left over from the big bang.
So when the universe was very small and young about 14 billion years ago, it was like a dense soup filled with particles.
As the universe evolved and it grew bigger, that soup really cooled off.
Today, we can sample the temperature of that primordial radiation across the universe.
We take measurements of huge numbers of tiny microwave patches, pretty much the way we would do a statistical analysis of Dragan's favorite pastime - basketball.
I really love basketball, and basketball court is a really good place to explain these cosmic microwave background alignments.
Here on the basketball court, we have, uh, Jimmy King, former University of Michigan basketball legend, and his buddy Willie Vance.
They will show us alignments and a cosmic microwave background using their shooting.
Looking out from the hoop onto the court is a lot like looking up from earth to see the cosmic microwave background.
Dragan can compare the made and missed shots in the game to the temperature fluctuations he sees in the early universe.
Just like we have hot and cold spots in the cosmic microwave background fluctuations, we have makes and misses in basketball.
So, we can represent each make with the red and miss with the blue.
Dragan maps the distribution of makes and misses across the half court.
The results show an even distribution, one that's symmetrical on both sides of the half court.
If Jimmy and Willie hit a shot from one spot, they can probably hit the same shot on the other side of the court.
So the distribution of the makes and the misses is about the same everywhere on the court - the same number of makes versus the misses.
This is what dragan and other researchers expected to find in the cosmic microwave background - an even distribution of hot and cold temperatures no matter where you look in the sky.
But that's not at all what dragan and his colleagues saw when they looked more closely at the pattern.
They found something so startling, so disturbing, cosmologists had no choice but to call it the axis of evil.
These alignments in the sky had been noted around the same time that George W.
Bush had his axis of evil, so they were named by scientists in England, the axis of evil.
We are not sure the axis is actually evil.
What we found analyzing causing microwave background data was instead, that one direction was special.
So, in basketball terms, it's almost as if one direction, relative to the basket, were tilted.
If a corner of the court that Jimmy and Willie are playing on suddenly shifted so that it now dropped off at an angle, it would make it harder to make a shot from that area.
The even distribution of makes and misses across the court would suddenly be disrupted.
We see more blue dots in the direction of the court.
And so you conclude that something is off about the basketball court.
If a basketball court were not flat, you would know something was seriously wrong.
Dragan feels the same way about the universe.
In the cosmic microwave background fluctuations, we see that the structure of the hot and cold spots is different, that they line up in one direction in the sky differently than they do in all the other directions, and that, maybe, tells us that something is different in that special direction in the universe.
The largest hot and cold spots are aligned along an axis that cuts right across the cosmos.
The results suggest that the shape of the universe is somehow distorted.
But what could alter the shape of the entire universe? We are still not completely sure what the cause is.
Is it just a fluke, or is it that there is a reason from the early universe? It could be, also, that this evil of axis alignments are caused by structures that we cannot see, and yet they're there, and they are creating the alignments.
Just as a world of light was shaped by dark matter, the entire universe may have been shaped by an even darker entity.
Could the shadow universe have a shadow, something that controls the very fabric of space and time? We used to see the black of night as the epitome of nothingness, but the darkness isn't empty.
It's full of strange material that has shaped our universe of atoms and light into what it is today.
In turn, that cosmos of dark matter could be a mere spot on the surface of some far bigger plane of reality.
The shadow universe could exist beyond space and time - a realm we can now only begin to dream of understanding.
Through The Wormhole S05E09