Dr Joao Magueijo: We did something which most people consider to be
a bit of a heresy. We decided that the speed of light could change in space
and time, and if that is true then our perceptions of physics will change
Narrator: At the dawn of a new century, a new theory is being born.
It threatens to demolish the foundations of 20th century physics. Its authors
are two of the world's leading cosmologists. If they're right, Einstein was
wrong. It all began when Andy Albrecht and Joao Magueijo met at a conference
in America in 1996.
Prof Andy Albrecht: This was pretty, exciting. Most of the key
people were there and there were lots of debates about the contemporary issues
in cosmology. Joao came up to me late one evening and had a very interesting
Dr Joao Magueijo: This is total bullshit! It wasn't like that at
Interviewer: Joao how do you remember it?
Dr Joao Magueijo: I remember there was this conversation between the
three of us, and then each one of us suggested something. I remember I
suggested the varying speed of light and there was embarrassed silence. I
think you two thought I was taking the piss at this point.
Prof Andy Albrecht: Maybe, possibly but
Dr Joao Magueijo: But then, oh he's actually serious, he's not
laughing; then we started taking it more seriously.
Narrator: For most scientists the idea that the speed of light can
change is outrageous; it flatly contradicts Einstein's theories of space and
time. But recently astronomers have begun to realise that the Universe doesn't
always behave as his theories would lead you to expect.
Prof Andrew Lange: We're making measurements which indicate that the
Universe is filled with some kind of energy density and we don't understand
this energy at all. It's unlike anything else in physical theory.
Prof Richard Ellis: And the surprise is that instead of the Universe
slowing down, in fact it's speeding up.
Prof John Webb: It's certainly a very profound result for physics
because it will be the first ever indication that the laws of nature were not
always the same as they are today.
Prof Richard Ellis: Who knows what's in store? I think in some way
it's a very exciting time: it's very similar to the revolution that was seen
in physics at the turn of the last century. So here we are about to enter the
new millennium with a whole lot of uncertainties in store.
Narrator: To understand what's at stake, we need to go back to that
scientific revolution. It began here in Bern Switzerland in 1905. As the new
20th century dawned, the intricate mechanism of 19th century physics was
beginning to show signs of strain. It was finally demolished, not by an
established scientist, but by a patent clerk.
Prof Dave Wark: When Einstein started his career, we still lived in
a Newtonian clockwork Universe. Space and time were simply a reference system.
The metre was a metre anywhere you went,and time clicked at a constant rate
throughout the whole Universe. It was unaffected by where you were, whether
you were moving or not.
Dr Ruth Durrer: Time was considered as an absolute concept - the
time would be everywhere the same, independent of the state of motion of
somebody. That there would exist an absolute time which could be measured with
a clock. This was the concept which Einstein smashed with his new thought.
Narrator: The tool that Einstein used to shatter the clockwork
Universe was the speed of light. He knew that for 20 years scientists had been
puzzled by an experiment which suggested there was something decidedly odd
about the speed of light. In the 1880s two American scientists, Albert
Michelson and Edward Morley set out to measure how the speed of light was
affected by the Earth's motion through space. They set up an experiment with
beams of light.
Prof John Baldwin: In this experiment there's a light source which
is the laser, and one's splitting the laser beam into two, sending them in two
directions at right angles, and measuring in a sense the relative speed of
light along those two beams and recombining them. The pattern that you see is
the interference between two beams and it's measuring the relative speed of
light within those two beams.
Narrator: If the apparatus were static there'd be no reason to
expect a difference between the beams, but in fact it's moving very fast
indeed. Our planet orbits the sun at 30 kilometres a second. It also spins
around its axis once a day so every laboratory on Earth is spinning through
Prof John Baldwin: Well at this time of day the Earth is moving in
this direction through space round the sun. If we then waited six hours, the
Earth would have turned and then this direction would be the direction of
motion of the Earth through space; then in another six hours this direction
would be back but reversed. So that by doing nothing you can just sit here and
very, very smoothly the Earth takes you round and then you can just look at
the stability of your apparatus.
Narrator: Michelson and Morley assumed that the planet speed would
add to the speed of the light beams and their apparatus. So they expected to
see a regular pulsing of the pattern every six hours as the Earth's motion
added to the speed of light in first one beam and then the other.
Prof John Baldwin: The surprising thing of course was that the
measurements showed that nothing happened, and no matter how they did it and
when they did it and whether they waited a long time, all year even, still
nothing happened. And that's the beauty of the experiment that if you can
measure nothing very, very precisely then you've got something really
Narrator: The importance of this result was that it proved that you
can never add to or subtract from the speed of light. This was a direct
contradiction to what was supposed to happen in the clockwork Universe. When
space and time are fixed, speeds must always add up.
Prof Dave Wark: In such a world one has a very simple rule for the
addition of speed, the addition of velocities. In Einstein's example, if
you're walking along a tram or a train, your speed, with respect to the ground
outside, is just the sum of your speed walking along the tram and the tram
speed with respect to the ground.
Narrator: But the Michelson, Morley experiment had proved that this
was not true for light. Light leaves the tram at the speed of light and
strikes the pedestrians at the speed of light and this speed never changes, no
matter how fast the tram is going. But something must change as a result of
the tram speed. Einstein realised that it must be space and time themselves.
Dr Ruth Durrer: Once you assume that the speed of light is the fixed
thing, this will imply that space and time can no longer be fixed and that,
for example, a moving clock which is moving with respect to you goes slower.
Narrator: So, viewed from the pavement, the speed of the light from
a tram is not affected by its motion. Instead the watch, as the passengers are
waiting, will run slow compared to a stationary clock. In a small two-room
apartment a few yards from the clock tower, Einstein wrote up his radical
theory of Special Relativity.
Prof Dave Wark: Advertisement for the unemployed Einstein offering
Dr Ruth Durrer: ...private courses in mathematics and physics for
students. For some time he was unemployed; nobody wanted him. They thought he
was too lazy.
Prof Dave Wark: I think they thought he was too troublesome. Does it
say there how much he charges?
Dr Ruth Durrer: It says that test lessons are free.
Prof Dave Wark: Ok, I think I'll come by and have a test lesson.
Narrator: But Einstein's fortunes were about to change.
Dr Ruth Durrer: So it's 1905, he's 26.
Narrator: In that year he published several papers of which
Relativity was just one.
Dr Ruth Durrer: Six papers if you count the PhD dissertation.
Prof Dave Wark: In one year. And each one founds a field of physics.
Dr Ruth Durrer: And each one is worth the Nobel Prize.
Prof Dave Wark: I wonder if he'd realised just how big a change he
was making to the world when he wrote that down.
Dr Ruth Durrer: And that's the E=mc2 paper, which he
published very shortly after that one.
Prof Dave Wark: Look how thin it is! Jesus! Three pages - if I could
trade all of my lifetime publications for these three pages!
Narrator: But Einstein himself was not satisfied. The problem was
that his theory of relativity broke down when gravity entered the picture and
gravity was the dominant force in the Universe. Einstein realised that he had
to take his notion of flexible space and time even further.
Prof Dave Wark: He had to give space-time actual properties, it was
no longer just in an empty place where things occur, it was something that
actually was interactive. So in his famous statement, mass tells space how to
curve, the presence of mass actually curves space-time.
Prof Dave Wark: And in the flip side of that, his next part of this
statement is: space tells mass how to move, so a mass moving through
space-time now just follows the curvature induced on it by the presence of a
Prof Dave Wark: And this solved an old problem from Newtonian
mechanics: the Earth is going round the sun. The Earth feels a gravitational
attraction to the sun. How does it do that? How does the Earth know the sun is
there? What is the source of this instantaneous action at a distance? In
Einstein's model there is no such instantaneous action at a distance. The mass
of the sun simply curves space-time and then the Earth follows that curve.
Just like this tram follows the tram line it is on in response to the local
curvature of the tracks; it doesn't know if those tracks are going to curve
some distance in advance; it doesn't need to know. It just follows the local
curvature of the track.
Prof Dave Wark: Einstein realised that it wouldn't just be mass that
would cause gravity, it wouldn't just be mass that curved space time.
Dr Ruth Durrer: Every form of energy, like heat or also pressure,
reacts to the gravitational field.
Prof Dave Wark: There's nuclear energy many, many different types of
energy and all of them cause space-time to curve the same amount, depending
just on the total amount of energy present. Mass is nothing special in this
Narrator: For 10 years Einstein searched for an equation to express
this relationship between mass-energy and space-time. In the end it was
stunningly simple. G = 8 p T. In five characters the Einstein field equation
encompasses the structure of the entire Universe. It ranks as one of the
supreme achievements of human thought.
Dr Ruth Durrer: When, as a student, you learn this theory you find
it extremely beautiful and simple. But then if you think: how did he get it?
How on Earth did he find out these equations? That's a miracle.
Narrator: But Einstein didn't stop. He set out to use his new
equations to describe the entire Universe. It was a bold leap and immediately
he ran into problems - problems which still remain.
Dr Joao Magueijo: Relativity was a great success at least until
Einstein had the courage to apply relativity to the Universe as a whole. He
invented cosmology, scientific cosmology, but at the same time he gave us a
lot of problems which are still with us. Basically, the Universe as we see it
doesn't want to behave according to relativity.
Narrator: Einstein's approach was based on a daring assumption. He
knew that locally stars would distort space-time in complicated ways that
would be too difficult to calculate. But he believed that if he stepped back
far enough, all the matter in the Universe would look like molecules in a
cloud of gas.
Narrator: The cosmological fluid. From this perspective, the shape
of space-time would be uniform and simple enough to deal with. But when he
began to calculate how the Universe would behave under the influence of
gravity he got a nasty shock.
Prof Dave Wark: You look out in the Universe and you see what
appears to be relatively stable: the unchanging stars. And in Einstein's era
they thought the Universe was remarkably static. It looked the same over time.
But in Einstein's solutions this couldn't be true.
Narrator: Einstein found that his equation predicted that all the
matter and energy in the Universe would fold space-time back upon itself. Soon
the Universe would meet a fiery end as all the stars and galaxies collapsed
into an enormous fireball.
Dave Wark: And in order to prevent this, Einstein had to add a term
which he called the cosmological constant.
Narrator: To Einstein this extra term, lambda, the cosmological
constant, spoilt the beauty of his original equation. But he could see no
other way to make the Universe stable.
Prof Dave Wark: Now this is a constant that gives space-time itself
the property that it would tend to spontaneously expand, and so he added that
constant in just the right amount so that this property of space-time to
expand would exactly balance the property of the matter in the galaxy or in
the Universe to collapse under its own gravity. So by exactly balancing these
two, he could therefore make the Universe stable. Now it wouldn't really have
worked of course because it's the stability of a pencil on its point. Even the
smallest deviation - too small a matter of density, too large amount of
density - would have made the Universe collapse or expand, so I don't really
think he'd solved the problem.
Narrator: Einstein's problem was that, according to his theory, the
Universe was inherently unstable; it should have collapsed or exploded long
ago. It's a mystery that worries scientists to this day.
Narrator: This is the echo of creation. Detune a television set and
it will pick up microwave radiation from the edge of the visible Universe.
When it' set out on its journey, it was orange light but over the 15 billion
years it has been travelling the Universe, it has grown a thousandfold,
stretching the light so that we now see it as microwaves. It warms us as it
warms the entire cosmos, raising the temperature of space by 3 degrees. This
signal is powerful evidence that the Universe is not unchanging as Einstein
imagined but that everything we see around us was once part of an immense
fireball. The first hints of that fiery beginning were found when astronomers
started to look out into space beyond our own galaxy.
Prof Richard Ellis: The 1920s was an exciting time in astronomy
because that's when the first large telescopes came on line and Edwin Hubble,
an American astronomer, started looking at nearby stellar systems which we now
TV voice: Dr Edwin Hubble on a moveable platform lines up the
massive telescope as he begins a cold night's work.
Prof Richard Ellis: And to his astonishment he found that they were
very, very far away firstly, and secondly by measuring the light from these
galaxies, he was able to see that they were moving away from us.
Narrator: To Hubble this could only mean one thing: the Universe
itself must be expanding.
Prof Richard Ellis: It's a pretty profound discovery that the
Universe is expanding because what that means is that at some point in the
past, things were closer together. So if you measured density - the number of
galaxies in a little box of space - then as you go back in time, the number
that fit in a fixed box of space goes up and so the Universe becomes much
denser and hotter. As one goes back in time, eventually you will come to a
point which we call the Big Bang when the density was extremely high. And so
the profundity of this discovery is that the Universe had a beginning: a Big
Narrator: If Hubble was right and the Universe had started with a
cosmic explosion, then the force of this alone might be enough to
counterbalance gravity's tendency to make the Universe collapse and die.
Perhaps here was a way to make the Universe stable and solve Einstein's
Prof Richard Ellis: You would have thought Einstein would respond
positively to observations, but as is often the case, theorists completely
ignore observations and so here was Hubble with a fantastic discovery -
probably discovery of the century - and Einstein really didn't take any notice
of it. So Einstein stuck to his static Universe, insisted on his cosmological
constant to keep the Universe static, and it wasn't really until a meeting
here in California between Hubble and Einstein in about 1932 that really there
was a synergy between Einstein and the expanding Universe.
TV voice: And here he comes, down from the sun tower after a hard
morning, looking a few million miles into his favourite space.
Narrator: Hubble, in the middle here, soon convinced Einstein that
the Universe was indeed expanding. The cosmological constant which Einstein
had introduced to hold up a static Universe against the force of gravity
appeared to be unnecessary after all. With relief Einstein returned to the
original form of his general theory of relativity.
Prof Richard Ellis: And it's at that time, or shortly after that,
Einstein said that the invention of this cosmological constant was his biggest
TV voice: The construction is very was very skilful. You had to
build up the outside and then put in the inside and then more outside and
inside it was a great piece of engineering
Narrator: But Einstein's optimism was premature. It has gradually
dawned on cosmologists that the Big Bang doesn't in fact solve the problem
with the Universe stability. For 21st-century physicists like Joao Magueijo
and Andy Albrecht, the cutting edge of research is still the problem first
identified by Einstein back in 1916.
Prof Andy Albrecht: If we can really make that connection, then it's
the reason why people should want the speed of light to vary.
Prof Andy Albrecht: You'd think, with all the great success of the
Big Bang, we'd be happy, we wouldn't be complaining. But there's a problem
with the Big Bang, and the problem is we shouldn't be here.
Narrator: The Universe has been gently expanding for 15 billion
years. That's allowed time for stars, planets and cosmologists to evolve. The
problem is, it's almost impossible to get a gently expanding Universe out of
the Big Bang. Either it expands too fast or it falls back in on itself. Either
way the Universe could not last very long.
Prof Andy Albrecht: A good analogy is to think about throwing a rock
in the air. You throw it up; you expect it to come back after a little while.
You throw a little bit harder and it goes further; but eventually comes back.
If you throw it hard enough and no human can do this but NASA can do it with
a space ship - you can leave the gravitational attraction of the Earth and fly
Prof Andy Albrecht: With the Universe there's this delicate balance.
You throw the rock in the air it keeps going. Is it gonna turn around? You
don't know, it keeps going, it keeps going, you don't see it flying off, you
don't see it turning around, it's balanced right at the end for year after
year, thousands of years, billions of years. We're now almost 15 billion
years, we still don't know - is it coming back is it flying off? That's what
the Universe is like.
Narrator: With the ball it's how fast you throw it. With the
Universe the key thing is the amount of matter and energy in the Big Bang. To
produce gentle expansion, the density of this energy has to be precisely
Prof Andy Albrecht: How do we start this Universe out in such a
special state? We have to take a number that describes the density of the
matter in the Universe and get it right to a hundred decimal places. One after
the other, if we get one decimal place wrong the whole thing gets out of
whack. No physicist can stomach setting up a Universe in such a delicate way.
Narrator: Yet something set up the Universe in the right way. Some
mysterious process made sure that matter and energy had everywhere the same
critical density keeping the entire cosmos in perfect balance.
Narrator: Scientists call this the flatness problem.
Dr Joao Magueijo: So this is the flatness problem: it's the fact
that the Universe is a bit like a pencil standing on its stick for 15 billion
Narrator: And it's even worse than that.
Andy Albrecht: The puzzle is that when you start saying OK, suppose
at the beginning things were different and something could come along and
adjust everything just the way you need it, you run into the following
problem: nothing can travel faster than the speed of light.
Narrator: The Universe is very, very big. Bigger than we can imagine
and bigger than we can see. There are regions of space so far away they are
invisible because the light from them has not yet had time to reach us. In
effect we are surrounded by a horizon; this horizon has been growing at the
speed of light since the Universe began but beyond it are regions with which
we have never had any kind of contact. Since nothing, not energy nor any kind
of physical process can travel faster than light, nothing can cross the
Dr Joao Magueijo: The Universe is now 15 billion years old which
means that the horizon is actually very large. Nowadays it's about 30 billion
light years across. This doesn't mean that the Universe is only this size; of
course the Universe is infinite. It just means the region we can see is this
30 billion light year region, and when the Universe is very young, it's still
very big but conversely you see a smaller and smaller fraction because the
horizon is smaller and smaller.
Narrator: To see what this means, imagine that we could travel back
in time. We would see the Universe shrinking rather than expanding, but our
view of it would shrink even faster because our horizon would be shrinking at
the fastest possible speed: the speed of light. Galaxies that are visible
today would have been invisible to us in the past, and to each other. So the
early Universe was divided up into small islands, isolated inside their own
small horizons. This picture of a disconnected Universe flies directly in the
face of the idea of a single balancing process needed to solve the flatness
problem. Confused? So were the cosmologists. The only way round this horizon
problem was to assume that the entire region we see today started out so tiny
it would fit inside a single horizon. This idea, called inflation, was first
proposed by Alan Guth and then developed by Paul Steinhardt and his colleague
Andy Albrecht. Today, their version of inflation is widely accepted among
scientists but Andy Albrecht himself has never been wholly convinced by his
Prof Andy Albrecht: What we have to do to make inflation work is
invent an entirely new form of matter that exists in the early Universe and
then disappears so we don't have it around today. And I was always left with
the nagging feeling that if you invent so much, is inflation really the right
thing to invent? Or could nature have chosen something else?
Narrator: As a young researcher at Cambridge in the mid-1990s, Joao
Magueijo was also sceptical about inflation.
Dr Joao Magueijo: Because inflation is the only thing available,
people cling to it, just like to a lifeboat. To be a bit extreme, you could
say, you could solve all these fine-tuning problems using divine intervention
and I think inflation is a scientifically acceptable way to invoke divine
intervention at some point.
Prof Andy Albrecht: I think that's a bit over the top but there's
enough open questions that we really need to think about it.
Narrator: One day Joao saw that there might be a much simpler way to
solve the horizon problem.
Dr Joao Magueijo: I realised that if you were to break one single
but sacred rule of the game, the constancy of the speed of light, you could
actually solve the horizon problem. And when you think back on it, it's just
such an obvious thing that when Universe is very young if the light was very
fast you could have a very large horizon. When the Universe was one year old
the horizon would be one quick light here across to here, which could be as
big as you wanted and of course you can connect the whole of your Universe if
you do this.
Narrator: If early light was much faster, a single horizon could be
big enough to encompass the entire known Universe. It was a bold idea, too
Dr Joao Magueijo: This came at the time when I was a fellow of this
college but it was also a stage in my career where I had to look for a job, I
was about to finish my position here - not the time to go and pursue a very
original idea. I was already quite controversial. I didn't need another thing
that would be even more controversial. There were times when I saw myself
selling the Big Issue outside St John's College! So I waited until I was on
much safer ground.
Narrator: Joao found that safer ground when the Royal Society
awarded him a rare and prestigious research fellowship. He joined Andy
Albrecht's group at Imperial College. They started to work on Joao's idea
Dr Joao Magueijo: One day Andy just called me to his office and he
said, 'Joao let's work on the varying speed of light here,' and he closed the
door and made a big secret about it. He cleaned the blackboard afterwards; he
was really afraid someone might steal the idea. Then gradually we just started
putting more and more material together, trying to find more and more things
about the theory.
Prof Andy Albrecht: You face the frontier, you face unknown
questions and you argue about it and you have competing ideas and, after a
while one is clearly the winner.
Dr Joao Magueijo: And you're really worried about something, it
really is with you all the time, not just in your office. You go through
phases in which you dream about your ideas, you sleep over your ideas you wake
up tired. Well you need to cast things into equations in the end because this
is what science is all about. It's about mathematical models not just
theories, otherwise it's all very cranky. I think there is a very unique
aspect of scientific discovery, there is a big adrenaline rush when you've
spent months and months struggling with the problem getting it wrong and
eventually you discover something and it's unique. I'm addicted to adrenaline
in general but this one is unique.
Narrator: Joao and Andy were creating a completely new physics. As
they explored this strange new world it began to dawn that perhaps they could
solve more than just the horizon problem.
Dr Joao Magueijo: We got more than what we bargained for and this is
really where the thing was massively rewarding. We found that we could solve
the flatness problem as well and the reason for that is we realised very
quickly there's no way we have energy conservation if the speed of light
Narrator: In conventional physics, energy is conserved. It can be
transformed but it cannot be created or destroyed. This is the principle of
the conservation of energy and it means that the total amount of energy in the
Universe is fixed. So the critical energy density the Universe needs must be
established perfectly, right from the beginning.
Dr Joao Magueijo: Now if we change something as fundamental as the
speed of light, which is woven into the whole fabric of physics, then of
course you're breaking that principle: the Universe is different at different
times. And you don't conserve energy. But then you realise this is exactly
what you need to solve the flatness problem because you violate energy
conservation pushing the Universe to the critical energy density. That is, you
create energy if you have sub-critical energy density and vice versa. You take
away energy if you have a surplus of energy density.
Narrator: In their theory, during the early Universe the speed of
light was falling, which allowed the cosmos a built-in thermostat, creating or
destroying energy so that the critical density was maintained exactly. Thus
the Universe remained in balance for billions of years.
Dr Joao Magueijo: We were just trying to find an alternative to
inflation as far as the horizon problem was concerned. We actually did not
have hopes of solving everything. This was a gift we got out of it.
Narrator: Joao and Andy had set out to solve the horizon problem and
stumbled upon a theory that solved the puzzle which had plagued cosmology
since the time of Einstein. They had made a Universe that was inherently
stable, held in balance by the creation or destruction of energy. A theory
which predicted the Universe as we see it today. However it was still just a
theory; proof could only come from the depths of space-time. But what
astronomers found there would astonish everyone. Suggesting that the speed of
light was also the key to the biggest mystery in cosmology: what happened
before the Big Bang.
Narrator: Long ago when the Universe was young, light itself
travelled faster than it does today. The laws of physics were very different;
that at least was the theory. The evidence could only come from the world's
great telescopes. As they scan the far depths of space, astronomers also look
back in time.
Narrator: In 1998 the British astronomer John Webb started to become
interested in the question of whether the fundamental constants of nature
could change as the Universe evolved.
Prof John Webb: We're using a technique which enables us to look
back into the past to measure physics as it was a long time ago. So we're
doing that using quasars.
Narrator: Quasars are the most distant objects we can see; they are
thought to be primitive galaxies in the process of formation. But John Webb is
not interested in the quasars themselves.
Prof John Webb: Quasars are just, as far as we're concerned for this
study, very distant sources of light which shine through the Universe to us.
In doing so, they intersect gas clouds along the line of sight and then we can
study the physics of those gas clouds by looking at the way in which the light
is absorbed. We can look at gas clouds relatively nearby, and we can look at
them just about as far away as the most distant quasars. That means in terms
of looking back in time almost 10 billion years, or something like that, an
awful long time ago. So we're studying physics as it was when the Universe was
Narrator: When light passes through an interstellar gas cloud it
collides with the electrons and the gas molecules. This creates a pattern of
dark lines in its spectrum. What John Webb noticed was that this pattern
looked different in the spectra from the most distant clouds. The inference
was astonishing: either the electrons were different or the speed of light was
greater in the distant past.
Prof John Webb: If it's correct, it's certainly a very profound
result for physics because it would be the first ever indication that the laws
of nature were not always the same as they are today.
Narrator: But far off in space and time an even more amazing
discovery was waiting for astronomers: today cosmology is buzzing with news of
the unexpected comeback of an idea discarded 70 years ago. Einstein's
cosmological constant, lambda.
Narrator: For Joao it means taking his theory even further. He now
believes the cosmological constant could be the link that connects changes in
the speed of light to the origin of the Universe itself.
Dr Joao Magueijo: So Einstein has already endowed space-time with
its own life, when he allowed space-time to curve, to have its own dynamics -
and the cosmological constant was one step further - it was basically giving
space-time its own energy so that even before he put matter into space-time,
when we have vacuum, you have some energy density in this vacuum and this is
what lambda is, and it has this very interesting property that essentially it
makes repulsive gravity.
Narrator: Lambda produces gravity that pushes things apart rather
than pulling them together and that seems to be what's happening to the
Universe, something is blowing it apart.
Narrator: Ever since Hubble convinced Einstein that the Universe is
growing, astronomers have been trying to measure its rate of expansion. The
breakthrough came when they started to concentrate on exploding stars called
supernovae. They thought that these would allow them to chart the gentle
deceleration of the Universe. What they actually found was precisely the
Prof Richard Ellis: Now the question is, is the Universe slowing
down as we would expect? The surprise is that instead of the Universe slowing
down, in fact it's speeding up.
Narrator: Something is upsetting the delicate balance of the
Universe, pushing the galaxies apart faster and faster. A new force in the
vacuum of space.
Prof Richard Ellis: The acceleration as seen from the supernova
data, of course, raises the amazing question of resurrecting Einstein's
Narrator: It looks as if space-time is humming with energy. Buried
in the equations of this theory, Joao has found a hidden link between this
energy and the speed of light.
Dr Joao Magueijo: Well at some point we've found out two interesting
things. One was that the energy in the cosmological constant also depends on
the speed of light, and in particular if the speed of light drops, then the
energy in the vacuum drops as well. And the second thing we've found is that
this cosmological constant itself promotes changes in the speed of light - it
can make it drop in value. So we have an instability.
Narrator: In Joao's theory, a change in the vacuum can cause a drop
in the speed of light, but this in turn reduces the amount of energy the
vacuum can hold, forcing energy out of it and into ordinary matter and
radiation. Could this be the genius of the Universe? What happened before the
Dr Joao Magueijo: So in some of these scenarios in the beginning
there is just a vacuum - but the vacuum is not nothing, it's actually the
cosmological constant, this pull of energy in the vacuum. And in these
theories, it is this energy that drives changes in the speed of light; it
makes a drop in value. And what that does is that makes all the energy in the
cosmological constant drop as well. It has to go somewhere. Where does it go?
It goes into all the matter of the Universe, so it caused a Big Bang. So in
this scenario it's actually this sudden drop in the speed of light - this
change in the speed of light - that causes the Big Bang.
Narrator: In the beginning was the void. But the void was not
nothing and there was light and the light changed. And so the void brought
forth the world and the world was good, for it endured until men could
comprehend it. But it will come to pass that one day the energy of the void
will have pushed all things away, leaving nothing but the void. But the void
is not nothing.
Dr Joao Magueijo: And you might think this is the end of the
Universe, but of course in the picture of this theory it's just creating the
conditions for another Big Bang to happen again - a sudden drop in the speed
of light, another sudden discharge of all this energy into another Big Bang.
So it is possible that actually our Big Bang is just one of many, one of many
yet to come, and one of many which there were in the past already - maybe the
Universe is just this sequence of Big Bangs all the time.
Narrator: Joao's bold challenge to the constancy of the speed of
light has led him to a wholly new view of the cosmos. One in which the
Universe no longer has a beginning and an end, but is eternal. An endless
cycle of Big Bangs drawn from the vast reservoir of energy in the vacuum. And
like every cosmologist before him, Joao has been guided by the theory that
started it all: it is a measure of Einstein's genius that even when he was
wrong, somehow he was right. What he called his biggest blunder may yet prove
his greatest legacy.
Joao Magueijo: Well of course I respect relativity enormously and I
have this feeling that it is only now that I have contradicted relativity that
I really understand it. And it's actually just because I've gone against it
that I'm showing my full respect to the great man. This is not at all trying
to contradict Einstein, it's just trying to take things one step further.
Eventually of course it will be nature that will decide whether this is true
or not. I'm working on trying to find ways of deciding whether the theory is
right or wrong. Some kind of experiment which will decide conclusively whether
the varying speed of light theory is pure nonsense or not.