EINSTEIN’S EXTRAORDINARY UNIVERSE-Centenary special of theory of relativity
One hundred years ago, Einstein’s theory of General Relativity was announced to the world. Black holes, time travel, and the Big Bang beginning of our universe are all consequences of Einstein’s great theory.
To celebrate, visit three ‘big physics’ facilities: CERN’s Large Hadron Collider in Switzerland; the vast dark matter laboratories under a mountain in Italy; and two three-kilometre rooms where scientists are hoping to prove a prediction Einstein made over a century ago – that gravitational waves exist. Don’t miss this celebration of Einstein’s ExtraordinaryUniverse.
(Ref:http://www.abc.net.au/catalyst/stories/4348650.htm)
(If you would like to read the transcript of the video read it below) but it is a visual delight so see it here Einstein’s Extraordinary Universe
NARRATION
We start our journey in Tuscany, a place famous for Renaissance artists. But these parts were also where the earliest scientific thinking about gravity began, by this man.
Dr Katie Mack
Galileo was the first person to think about gravity in terms of being a kind of universal thing.
NARRATION
Galileo Galilei lived in Pisa, not far from this Italian tourist icon. It’s not a bad tourist attraction. But there’s something far more exciting just around the corner. A few twists and turns through the back streets of Pisa and there it is, the house Galileo was born in.
Dr Graham Phillips
Now that’s a tourist attraction, the birthplace of one of the great men of science.
NARRATION
Eh, funny, no tourist crowds here. And the building’s a real estate agency these days. But, of course, that other attraction is one of the great icons of science, too. Legend has it it played a leading role in Galileo’s theory of gravity.
Dr Katie Mack
Previous to him, it was thought that a heavier object would fall faster than a lighter object. You know, it was just kind of common knowledge.
NARRATION
By dropping different weight balls from the top, Galileo demonstrated they all hit the ground at exactly the same time.
Dr Graham Phillips
Now, Galileo’s insight was pretty amazing. How on earth would you conclude that a stone and a feather are pushed along by the force of gravity at exactly the same speed?
NARRATION
It doesn’t appear that way because of air resistance, a force that pushes up against gravity. But remove the air from a couple of chambers and this sponge and ball bearing accelerate at exactly the same rate, just as Galileo predicted. And we eventually had unearthly proof of his great insight that all objects fall at the same speed.
Dr Eric Thrane
So, an astronaut on the surface of the moon has dropped a feather and a hammer…
David Scott
I’ll drop the two from here and hopefully they’ll hit the ground at the same time. How about that?
NARRATION
Now, that’s great confirmation for the traditional understanding of gravity. But I’m off to a place just down the road from Pisa where physicists are again working at the cutting edge of gravity research. This time they’re searching for those things in the universe Einstein predicted 100 ago, yet have never been found. And they’re truly weird. Waves of gravity. Think about it. Waves of water make sense. They’re ripples in water. But a gravitational wave is a ripple in nothingness, in empty space itself. In fact, it’s a ripple in space and time, whatever that means.
Professor Rafael Lang
Space and time, it’s like rubber. You can deform it, you can have ripples, you can have distortions, you have warpings.
Professor Federico Ferrini
It’s just the formation, the space-time. So it’s like an angel that moves his wings. (Chuckles)
NARRATION
To understand, you need to know a little about Einstein’s general relativity. He showed why all objects fall at the same speed. It’s because gravity is not really a force, it’s kind of an illusion. Einstein’s breakthrough was to treat space and time as actual things.
Dr Eric Thrane
Before Einstein, space-time was like a theatre where events took place, but it wasn’t a player in the show. After Einstein, after general relativity, space-time does stuff – it acts, it warps and it can carry energy, it moves.
NARRATION
Indeed, gravity is just warped space-time.
Dr Katie Mack
This can be thought of as space-time. So, you have sort of a flat grid. So if you take something with mass…
Dr Graham Phillips
So, that could be the sun.
Dr Katie Mack
It could be the sun. You can see it causes this sort of dent and it sort of bends the space-time. And so if you take something like this, maybe the Earth…
Dr Graham Phillips
Yeah.
Dr Katie Mack
..and you stick it on this bent space-time, it’ll go round in a curve, in a sort of orbit around this massive thing because it’s trying to move in a straight line, but the thing it’s moving through is not flat.
Dr Graham Phillips
So it’s not like the sun has this force that’s pulling it in. It’s just that it’s naturally going around because of the bent space-time.
Dr Katie Mack
In a sense, yes. Things are trying to move in straight lines and just moving in the sort of most natural shortest path, and that ends up being a curve if the space-time itself is curved.
NARRATION
And gravitational waves are just ripples in space-time. And they should be rippling throughout the cosmos. If we discover them, they offer a picture of our universe way younger than anything we’ve observed before.
Dr Eric Thrane
If we can detect them, it would be a remarkable moment in the history of astronomy.
NARRATION
To search for them, researchers have built this single room that’s 3km long. Inside it is a single long tube.
Dr Graham Phillips
So this tube stretches 3km?
Professor Fulvio Ricci
3km.
NARRATION
And inside the tube is nothing, a vacuum better than the one in space. They achieve it using ultra-high vacuum technology, just as they do at CERN to make the vacuum inside the Large Hadron Collider.
Professor Fulvio Ricci
This is the largest ultra-vacuum system in Europe. I’m just saying Europe because there are the other two machines in the United States which are longer.
NARRATION
Yep, the US has two 4km long gravitational wave detectors. Who says physicists aren’t competitive?
Dr Graham Phillips
So it’s the second-biggest vacuum in the world.
Professor Fulvio Ricci
The second-biggest vacuum, yes.
Dr Graham Phillips
And bigger than CERN, more importantly.
Professor Fulvio Ricci
Bigger than the LHC because it’s true that the ring is 27km long, but the volume is much more smaller.
Dr Graham Phillips
CERN’s not a vacuum. That’s a vacuum.
Professor Fulvio Ricci
That’s a vacuum. (Laughs) We are challenging CERN.
NARRATION
We’ll discover why this ultra-vacuum is so important shortly. First, you need to see the big picture.
Dr Graham Phillips
So there’s 3km of tube this way and then at right angles, there’s another 3km out that way.
Professor Fulvio Ricci
Yes.
NARRATION
That’s because the key to all gravitational wave detectors is to have two identical buildings at right angles to each other. When a wave passes, it bends the very space-time it moves though, temporarily changing the length of the buildings. Indeed, changing the length of everything.
Dr Eric Thrane
Were one to pass through me right now, you’d see me get slightly taller and slightly skinnier one moment, and then the next moment I would get slightly fatter and slightly shorter.
Dr Graham Phillips
When a gravity wave passes through here, the building stretching out to the north 3km might become ever so slightly shorter. Whereas the building to west could become that tiny, tiny bit longer. And they can actually measure that difference.
NARRATION
They do it by shining laser beams down those ultra-vacuum tubes. A single beam is split in two and is reflected back and forth between mirrors. If those laser beams become even slightly out of sync, it means they’re travelling different distances, and so the buildings must have different lengths caused by a gravitational wave.
Dr Graham Phillips
To give you a feel for how precisely this equipment can measure distances, one atom is less than a billionth of a metre across. Well, they’re measuring distances that are one-billionth the size of an atom.
Dr Roberto Trotta
That’s tiny. It’s incredible that we can even imagine we’ll ever be able to experimentally determine these changes.
NARRATION
But we can. The key is to keep the mirror-laser system rock steady. Even the vibrations from distant traffic must be blocked out. And that’s where that ultra-vacuum comes in. Sounds from the vibrations can’t travel through the vacuum in the tube, just as sound can’t travel through the vacuum up here. That’s why no-one can hear you scream in space. And other vibrations must be kept out as well.
Professor Federico Ferrini
If there is an earthquake in Japan of quite large intensity, our mirror oscillate. So we have to take care about that.
NARRATION
They do it by hanging the mirrors from 10m long chains of heavy pendulums, like this one. Physics demands, as you move down the chain, vibrations are steadily reduced by a factor of ten million billion at the bottom.
Dr Graham Phillips
So that isolates the equipment from pretty much everything.
Professor Carlo Bradaschia
Maybe our mirrors are the most quiet object in the universe.
NARRATION
The mirrors themselves have to be near perfect, hence clean-room construction. The first thing you notice is you can’t even see your reflection in them.
Dr Graham Phillips
This is one of the mirrors. It’s completely see-through, I hear you say. Now, that’s true for visible light. But the infra-red radiation, and that’s the wavelength the laser operates at, that surface is almost completely reflective. 99.9999% of the laser light is reflected back.
NARRATION
The gravitational wave detector will be finished and gathering data from space in the next two years. Different astronomical objects give off different patterns of gravitational waves.
Dr Eric Thrane
So if you actually take a gravitational wave signal and convert it into an audio file, of a binary black hole system, it sounds like this, ‘Gooo-yip’. And that’s a chirp.
NARRATION
And other objects emit gravitational waves too.
Professor Federico Ferrini
These waves need a very large mass concentration and very peculiar phenomena.
NARRATION
One of the most peculiar phenomena is a neutron star.
Professor Federico Ferrini
Oh, it’s a terrible object. (Chuckles) Imagine to have you the sun and shrink it to a diameter of 10km.
NARRATION
Given our sun is currently 1.5 million kilometres across, that 10km ball would be an extraordinarily dense dead star. A handful would weigh as much as a mountain. And these stars can spin up to 700 complete rotations every second.
Dr Eric Thrane
And they would sound more like a pitchfork being struck, something like, ‘Booooop’. Supernova, on the other hand, exploding stars are messy, complicated events, and so they would have a dirty sound and a short duration. It maybe sounds like, ‘Psshh!’
NARRATION
In the future, with detectors in space, we might eventually even pick up the gravitational waves from the Big Bang itself.
Dr Eric Thrane
These gravitational waves, from the very beginning of time, when the universe was less than one second old, are probably still around with us today.
NARRATION
Detecting them would be a stunning confirmation of Einstein’s extraordinary universe. Einstein lived in several countries, but his longest citizenship was to this one. We’re visiting to find out about one of his theory’s most dramatic implications – the Big Bang.
Dr Graham Phillips
We’ve come to Switzerland to visit physicists who are studying the Big Bang by creating their own mini Big Bangs. And they do it by using the biggest machine on the planet – the Large Hadron Collider.
NARRATION
The heart of the machine is a long circular tube… with, I guess, the third-best vacuum in the world. Inside it, subatomic particles rush around, colliding at almost the speed of light. Actually, I first visited CERN in 2008, before it was switched on. Then it was safe to go down into the tunnel. Emmanuel Tsesmelis gave me the grand tour on very dodgy CERN-issue bikes.
Dr Graham Phillips
So, if we just keep riding 27km, we’ll eventually come back to where we are.
Professor Emmanuel Tsesmelis
Yeah, we’ll come back here. We’re about 100m underground as well. That’s the other thing we should not forget.
Dr Graham Phillips
Yeah. I mean, it’s a massive, massive construction. 27km of this high-tech equipment.
Professor Emmanuel Tsesmelis
I think what you’re looking here is probably the most advanced scientific instrument we’ve ever constructed.
NARRATION
The advanced instrument smashes protons together. They’re just atoms of hydrogen that have had their electrons stripped off. And the smashes occur at incredible speed.
Dr Graham Phillips
Now, this really is mind-boggling stuff. Inside here, there are protons whizzing around the circuit. And they travel in bunches, there’s about a hundred billion protons per bunch, and there are a few bunches spread around the whole 27km. They’re travelling at 99.999999 – that’s eight nines – per cent of the speed of light, and then they’re brought into a head-on collision. Now, for the last couple of years, they’ve had the Large Hadron Collider switched off while they soup it up and get it ready to turn on at full energy.
NARRATION
To find out what they’ve been doing to the LHC during shutdown, I caught up with Emmanuel again.
Dr Graham Phillips
Hey, Emmanuel, how are you?
Professor Emmanuel Tsesmelis
Graham, welcome back.
Dr Graham Phillips
Yeah, seven years I think it’s been.
Professor Emmanuel Tsesmelis
Welcome back.
Dr Graham Phillips
Thank you.
Professor Emmanuel Tsesmelis
And I hope you can see a lot of new things after seven years.
Dr Graham Phillips
Alright, let’s have a look through.
Professor Emmanuel Tsesmelis
OK.
NARRATION
The key changes they’ve made involve these superconducting magnets, which are the backbone of the LHC. They steer the beams of particles around the 27km, and this is just one of them.
Professor Emmanuel Tsesmelis
And, as you can see, it’s about 15 metres in length. Each one of these magnets weighs about 35 tonnes and there’s 1,232 of them in the machine. So it’s not a tabletop magnet. You can’t put this on your fridge, unless you have a very big fridge.
NARRATION
They’re special, because when cooled to -271 degrees, they’re superconductors of electricity and so can generate enormous magnetic fields. The main job during shutdown was to upgrade the connections between the magnets so they could handle the LHC running at full operating strength.
Professor Emmanuel Tsesmelis
These interconnections between neighbouring magnets, these are superconducting interconnections to transfer the current all around the machine. And currents are reaching up to 12,000 amperes.
NARRATION
That’s some current. Just one-fifth of one amp is enough to kill you.
Professor Elisabetta Barberio
Hi. How are you?
Dr Graham Phillips
Yeah…
NARRATION
The LHC has been turned back on and the scientists are, well, like kids waiting for Santa.
Professor Elisabetta Barberio
And that’s why it’s exciting. Again, it’s like, you know, being Christmas, and you have a box with a present and you don’t know what it is and you… You’re very excited and they say, ‘No, no, you cannot open it until Christmas.’
NARRATION
This is where the real pressure was during switch-on, the room that runs the Large Hadron Collider.
Dr Graham Phillips
This is mission control for CERN.
NARRATION
Mike Lamont is the boss, ultimately responsible for keeping the LHC working.
Dr Graham Phillips
I mean, it looks like a complicated machine.
Dr Mike Lamont
It is complicated. You go down there and you look at some places and you just shake your head and, you know… It’s just amazing that it ever works at all.
NARRATION
It takes up to 13 operators, plus their technical assistants. And the pressure not to make a mistake is enormous because that beam of protons in the tube travels with the energy of a high-speed train.
Dr Mike Lamont
You’ve got collaborations of 2,000 people out there and they’ve spent their careers building these precious detectors and they do not want us sticking a beam in them.
NARRATION
No wonder they celebrate each success.
Dr Mike Lamont
It was tough in 2008, it was tough in 2010. I mean, that was… my guts still knot up thinking about it.
NARRATION
This latest restart was relatively easy. Mike’s got used to the pressure. When the protons smash into each other, it’s like creating little Big Bangs, possibly leading to a new understanding of gravity even beyond Einstein.
Professor Emmanuel Tsesmelis
The conditions of the collision are simulating those conditions really at the outset of the universe 13.8 billion years before. So it’s like a millionth of a millionth of a second after the time zero.
NARRATION
Indeed, CERN’s created little Bangs that are the hottest conditions ever made by humans, more than a staggering four trillion degrees. That’s a billion times hotter than the surface of the sun. With the machine running at full bore, the scientists are hoping to create yet more particles new to physics. Indeed, they might even create an extremely exotic one.
Dr Graham Phillips
It’s a remote possibility, but in principle, you could even create a micro black hole.
Professor Emmanuel Tsesmelis
If we’re lucky, we will. They would decay very quickly. We will not see the black hole itself, microscopic black hole, but we will see the decay products, a splash of energy in our detector. It would be terribly exciting if we do. Probably even more exciting than discovering the Higgs boson in a way, ’cause it’s something which… it’s really out there.
Professor Elisabetta Barberio
They looked for these also in the previous run, but we could not reach the energy high enough that we are going to reach now. So now we can probe if the black hole exists at a higher energy.
NARRATION
Theory says if we can create microscopic versions of these, the universe must be very strange indeed, with extra dimensions, and possibly even parallel universes. That would make the universe even more extraordinary than perhaps even Einstein imagined.
Dr Graham Phillips
Now, of course, no special on Einstein would be complete without asking ‘could Einstein have been wrong?’ Well, some physicists say not so much that he was wrong, but that his theory was incomplete, and their argument involves something very mysterious sounding – dark matter.
Dr Roberto Trotta
Dark matter is one of the biggest mysteries in physics.
Professor Rafael Lang
We can see its effects, but we just don’t know at all what it really is.
NARRATION
Ordinary matter is what everything we see is made of – stars, planets, you and me. Dark matter is a proposed different kind of substance. It’s all around us, even down here on Earth, but it’s invisible. Indeed, ghostly.
Dr Graham Phillips
Dark matter particles pass straight through everything. In a second, about a billion pass just through the palm of my hand and, of course, I don’t even notice.
NARRATION
Scientists deduced that dark matter exists because of the way our galaxy spins.
Professor Rafael Lang
As it turns out, the Milky Way is rotating way too fast. The stars are whizzing around like crazy. So, you know, the whole thing should be blowing apart.
NARRATION
Our galaxy is not blowing apart because the combined gravitational pull of all the matter in it holds it together. The problem is there’s not enough ordinary matter to provide sufficient gravity. There must be another source of gravity.
Professor Rafael Lang
So where does the gravity come from? We don’t see enough matter for that gravity. So we say it has to be extra matter, that’s dark matter.
NARRATION
Indeed, to provide enough force, the dark matter particles must outnumber the ordinary ones five to one.
Dr Graham Phillips
So it’s sort of the dominant matter and we have no idea what it is.
Professor Rafael Lang
That’s right. That’s right.
Dr Graham Phillips
Isn’t that disturbing?
Professor Rafael Lang
No, it’s great. It’s a fantastic opportunity. I mean, it’s like, ‘My God, we know it’s there!’ You know there’s this huge uncharted territory. You just have to go there and start charting it.
NARRATION
But do we know it’s there? A small number of critics say we could get rid of the whole idea of dark matter by changing Einstein’s equations.
Dr Graham Phillips
So, could Einstein’s relativity be incomplete in some way?
Dr Roberto Trotta
Well, we don’t know, really, because although the theory of general relativity has been tested very precisely on relatively small scales, what if it fails on very large scales? On the scales of galaxies or clusters of galaxies. So some people say that this might be the case and what we attribute to dark matter in the universe is actually a failure of gravity and Einstein was wrong or not totally right.
NARRATION
So physicists are desperately searching for dark matter beneath these Gran Sasso mountains in Italy. Inside are the biggest underground labs in the world. They’re so big, you can’t walk to them from the offices above ground. You have to catch the courtesy bus, which heads out just on the regular freeway, complete with regular toll booths. Through a tunnel or two and eventually you come a strange turn-off. You half expect to see a character from a James Bond movie here. Now, the key to a dark matter detector is shielding, because to pick up the faint signal of a ghostly dark matter particle, the detector has to be shielded from all stray ordinary matter particles. That’s why the labs are underground. The surface is continually bombarded by radiation.
Dr Roberto Trotta
For example, although we are mostly unaware of those, there are very high energy particles coming in from space called cosmic rays.
NARRATION
The 1.5km of rock above filters out most of this space radiation. The ghostly dark matter particles, of course, pass straight through.
Dr Graham Phillips
Hey, Jacques. It’s Graham.
Jacques Pienaar
Nice to meet you, Graham.
Dr Graham Phillips
Yeah, likewise. What a lab!
Jacques Pienaar
Yeah, it’s quite an impressive facility.
Dr Graham Phillips
I’ve seen some impressive labs in my time, but this one takes the cake, I think.
NARRATION
This is one of the experiments to detect dark matter. It’s called the XENON experiment – three storeys of high-tech gadgetry. Although much of it is further shielding for the detector.
Dr Graham Phillips
So this whole chamber will be full of water?
Jacques Pienaar
Yep. The idea is to provide additional shielding.
NARRATION
The detector will sit in the middle of this tank and the surrounding water will block more natural radiation from the rocky walls inside the cavern.
Dr Graham Phillips
And it is just regular water or do you need special water?
Jacques Pienaar
We’ll be filling this with deionised water because we want the water as pure as possible. We don’t want radioactive backgrounds from the water itself getting into the detector.
Dr Graham Phillips
Right. So you’ve got to shield from the natural radioactivity in water.
Jacques Pienaar
Yeah. Every single piece that goes in the detector is also being screened individually. So we know how radioactive it is and we can account for that when we’re doing our data analysis afterwards.
NARRATION
Some detectors in this magic mountain of experiments use lead for additional shielding. Of course, it has to be pure, too. So it comes from an unusual source.
Dr Graham Phillips
This is a lead ingot made by the ancient Romans. For the last 2,000 years, it’s been sitting at the bottom of a sea in a shipwreck, and it’s only recently been recovered. Now, it turns out it’s the most pure lead on the planet. Perfect for making shielding for dark matter experiments.
Dr Roberto Trotta
That lead’s lost all of its radioactivity by sitting at the bottom of the Mediterranean, say, for the past 2,000 years.
NARRATION
As well as shielding, a lot of the infrastructure is pipes and tanks because a special liquid is used as the detector – a large vat of the chemical xenon. Basically, the xenon atoms just sit there, waiting for a dark matter particle to collide with one of them. When that happens, a detection’s been made.
Jacques Pienaar
So, if we come up here, we can see the centre of the detector, where the actual science will be happening.
Dr Graham Phillips
Ah, yeah! OK, so the liquid xenon is inside there.
Jacques Pienaar
That’s correct. We have the outer vessel. Then inside that we have a slightly smaller stainless steel vessel, and it’s in that inside vessel that we’ll fill up with liquid xenon to look for the dark matter events, where all the instrumentation will sit.
NARRATION
Now, you might be wondering, if dark matter particles pass through everything, won’t they just pass straight through the liquid xenon detector?
Jacques Pienaar
The vast majority of them most likely do. The idea is… that’s why we built the detector as large as possible to try and increase the chance that one of those particles will eventually interact in our detector.
NARRATION
Very occasionally, a dark matter particle will collide with an ordinary matter atom, like a xenon atom.
Jacques Pienaar
We’re looking for that one single one-in-a-year that might interact.
NARRATION
Making even one detection would open the door to some extraordinarily exciting possibilities.
Professor Rafael Lang
Look, there’s so much dark matter out there than normal matter and look how rich our world is. And so you begin to wonder, if I have five times more stuff, what wonders could be hidden in this dark universe? You know, there’s absolutely no evidence whatsoever that there would be dark planets and dark people wandering around. But there’s also nothing that says that this can’t be.
NARRATION
It’s speculative, but our world could be surrounded by a dark matter parallel universe without us being aware of it. While we haven’t found any dark matter yet, most physicists believe it does exist.
Dr Roberto Trotta
The fact is that we have so many different lines of evidence pointing to dark matter.
NARRATION
So Einstein’s theory is probably safe. Indeed, dramatic new confirmation for his work would come with the first detection of gravitational waves.
Professor Rafael Lang
That would be huge discovery. That would be just mind-blowing. By all expectations, we will live to see that happen. The experiments are getting really close to doing that.
NARRATION
Indeed, the American detectors have just been switched on. We could pick up a gravitational wave any time.
Dr Eric Thrane
Until now, we’ve been completely deaf to these gravitational wave sounds. So we will be hearing the symphony of space-time for the very first time.
NARRATION
Not only would Einstein’s 100-year-old prediction that gravitational waves exist have been proved, a whole new window on our universe would open up
