Phew! Topics can’t get any bigger than this. On BBC Four this past fortnight, in The Beginning and the End of the Universe, the ever-lucid Jim Al-Khalili tackled two cosmic questions: how did the universe begin, and how will it end? I’ve written here before about my admiration for Al-Khalili’s ability to explain clearly and with elegance very difficult, abstract concepts (at least for a non-scientist) without ever dumbing-down. In these two documentaries he told the very human – and gripping – story of the scientists, both men and women, who in the last hundred years have succeeded in boggling our minds with concepts like the Big Bang, dark matter, and dark energy, as well as scientific tools such as redshift, the Hertzsprung-Russell diagram, and gravitational lensing.
A man said to the universe:
‘Sir, I exist!’
‘However,’ replied the universe,
‘The fact has not created in me
A sense of obligation.’
– Stephen Crane, ‘A Man Said to the Universe’
A science documentary from Jim Al-Khalili is always a model of clarity. In the past few years, watching programmes he has made for BBC Four, such as Light and Dark, Order and Disorder, The Story of Electricity, and Everything and Nothing, I have felt (at least for an hour or two) that I have understood at least a little of the complex mysteries of physics and cosmology. In these two films Jim was at his best, weaving human stories of chance and brilliant scientific investigation into crystal-clear expositions of the new ideas that have transformed our understanding of space and time. And he did this without any fancy graphics or special effects.
These jottings represent a complete non-scientist’s attempt to get down what he thinks he learned. Don’t rely on this for accuracy!
In the beginning …
Jim began by noting that it took science hundreds of years to ask an obvious question: ‘where did the universe come from?’ It is, he said, such a quintessentially human question, like asking ‘where did I come from?’
The reason for the delay was, of course, due to the hold which religion had on people’s minds. Thus it was not until the mid-20th century that science built a convincing and coherent creation story of its own. But, unlike the stories told in religious belief or older creation myths, science’s creation story was one based on theory, predictions, and observation. Its purpose, like ancestral creation myths and religious narratives, was to explain what happened at the very beginning of time.
We thought we knew what the universe was like: until a hundred years ago it was understood to be eternal, infinite and stable: no beginning and no end. Our galaxy – the Milky Way – remained the full extent of the known universe until the 1920s. That is, every single star in the night sky.
But, the giveaway was always there in the night sky. Discernible even to naked eye if you know where to look is the faint smudge of Andromeda – just one of many nebulae (literally, cloudy objects) scattered throughout the night sky. In 1923, Edwin Hubble, using what was then the biggest telescope in world at Mount Wilson Observatory overlooking Los Angeles, reshaped our knowledge of the universe by making observations of a star in Andromeda and working out that it was 900,000 light years away – in other words, well beyond the boundaries of our own galaxy. It turned out that there were many more galaxies located far outside our own. Instantly ideas about the size of the universe were utterly transformed. It was:
A moment in human consciousness when the universe had suddenly and dramatically got considerably bigger.
The next big shock would come four years later and ultimately reveal that even Einstein could get his sums wrong (correction, he got his sums right – but didn’t believe the answer). One of the theoretical foundations of his theory of relativity was that gravity was caused by the warping of space-time by massive objects like planet or stars. The implication was that the universe would eventually end in a massive crunch as gravity pulled everything together. However, like everyone else, Einstein believed that the universe was eternal and stable. So to make his theory work, he had to add the made-up force of anti-gravity – the ‘cosmological constant’ – to his equation.
But in 1927, the Belgian physicist and ordained priest, Georges Lemaître rejected Einstein with a theory that implied the universe was expanding – thus predicting the concept of the Big Bang. Einstein rejected Lemaître’s theory as ‘abominable’.
Two years later, it was Hubble who confirmed Lemaître’s theory when he confirmed that all galaxies seemed to be receding from us with velocities that increased in proportion to their distance from us. By measuring the redshift of celestial objects, he found that the further away galaxies were the faster they were moving away from us. Winding back the clock, that implies there was once a time when all the galaxies ‘were squeezed together in the same place’. Jim explained all this with the help of nothing more than a plastic slinky. Either he’s a genius – or the BBC cuts mean no wasting money on expensive props!
At this point Jim did some hard sums as a bunch of astronomers replicated Hubble’s original investigations. His sums showed that a galaxy one and a half billion light years away from ours is moving away from us at 30,000 kilometres per second. ‘Boom. Science!’ he exclaims. Realising his error, Einstein recanted and wrote to Lemaître to apologise. The ‘cosmological constant’ became an inconstant, dropped from his equation.
Next question: where did all the matter in the universe come from? To answer that question, Jim observed, we first need to know what it’s made of. The answer was worked out in the 1920s by Cecilia Payne who studied at Cambridge, but wasn’t awarded a degree ‘because – well – she was a woman’, and so left for America. There, she made observations and calculations which concluded that the sun (and therefore other stars) are made up primarily of just two elements – hydrogen and helium. Between them, these two elements compose 98% of all the matter in the universe.
And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters.
– Genesis 1.2
OK. Next question: how were hydrogen and helium forged in the first seconds of the Big Bang? The answer to that came in 1948 when George Gamow, aided by Ralph Alpher, published a paper setting out calculations that showed how, around three minutes after the Big Bang, what existed was a ‘super-heated primordial soup’ so hot that atoms didn’t exist. Their calculations showed that within 15 minutes a process of nuclear fusion would have created hydrogen and helium – in the exact ratios that matched those in the stars.
As a joke, when the paper was published, Gamow decided to add the name of his friend, the eminent physicist Hans Bethe, thus christening it the Alpher – Bethe -Gamow paper, a play on the Greek letters α, β, and γ (alpha, beta, gamma). Throughout the series, Jim would add these human touches, usually prefaced by him pulling out of his pocket a photo of the person whose story he was about to tell.
Pausing for moment and reflecting on the primordial soup that gave birth to the elements that define our world, here’s a poem written by Richard Feynman, an American theoretical physicist known for his work on quantum mechanics. In it Feynman imagines the emergence of complexity and consciousness from the blind play of atoms, mindlessly minding their own business:
There are the rushing waves
mountains of molecules
each stupidly minding its own business
yet forming white surf in unison
Ages on ages
before any eyes could see
year after year
thunderously pounding the shore as now.
For whom, for what?
On a dead planet
with no life to entertain.
Never at rest
tortured by energy
wasted prodigiously by the Sun
poured into space.
A mite makes the sea roar.
Deep in the sea
all molecules repeat
the patterns of one another
till complex new ones are formed.
They make others like themselves
and a new dance starts.
Growing in size and complexity
masses of atoms
dancing a pattern ever more intricate.
Out of the cradle
onto dry land
here it is
atoms with consciousness;
matter with curiosity.
Stands at the sea,
wonders at wondering: I
a universe of atoms
an atom in the Universe.
And God said, Let there be light: and there was light. And God saw the light, that it was good: and God divided the light from the darkness.
– Genesis 1.3
The aforementioned Alpher continued his investigations into the first moments of the universe and in 1949 concluded that minutes after the creation of hydrogen and helium, light would have been released for the first time to travel freely across the universe – ‘the first light of creation’. He realized that this light should still be reaching us now, though very faint, as microwave radiation. Detect this weak signal, and the Big Bang theory would be proved. The problem was that in the 1940s there was no equipment capable of doing that.
Fast-forward to 1964. Quite by accident, two radio astronomers, Arno Penzias and Robert Woodrow Wilson, using ‘a strange-looking telescope that looked like a giant ear-trumpet’, find they can’t get rid of an annoying background noise that’s interfering with their measurements. Only later, discussing the problem with fellow-scientists, did they realise that they had discovered the background radiation signal that had travelled across the furthest reaches of space from 13.8 billion years ago: proof of the Big Bang. There it was, the proof all around us. As Penzias said, ‘When you go outside you’re getting a tiny bit of whoomf from the Big Bang’.
Summing up at the end of the first programme, Jim Al-Khalili said that we have now got very close to the Big Bang in our understanding. But questions remain: where did the original matter come from? How do you get something from nothing? The answers, he said, lie further back: in the primordial universe, within the very first seconds of its existence.
Arriving at CERN, he said, ‘this where the edge of our understanding now lies’. In those first seconds of creation everything was confined in a small, phenomenally hot and high-density space. Then the first matter came into existence – and it is at CERN that the properties of fundamental particles are being investigated by the Large Hadron Collider. The knowledge we have already gained at CERN means we’ve got to one-millionth of a second after the Big Bang itself. Beyond that point some of the deeper mysteries of the universe hide.
It begins as a house, an end terrace
in this case
but it will not stop there. Soon it is
which cambers arrogantly past the Mechanics’ Institute,
at the main road without even looking
and quickly it is
a town with all four major clearing banks,
a daily paper
and a football team pushing for promotion.
On it goes, oblivious of the Planning Acts,
the green belts,
and before we know it it is out of our hands:
hemisphere, universe, hammering out in all directions
mercifully, it is drawn aside through the eye
of a black hole
and bulleted into a neighbouring galaxy, emerging
smaller and smoother
than a billiard ball but weighing more than Saturn.
People stop me in the street, badger me
in the check-out queue
and ask “What is this, this that is so small
and so very smooth
but whose mass is greater than the ringed planet?”
It’s just words
I assure them. But they will not have it.
– Zoom! by Simon Armitage
For ever and ever. Amen.
In the second programme Jim Al-Khalili explored what is understood at present about how the universe might end. If we can understand how the universe has evolved to the present moment, Jim explained, then we should be able to extrapolate and predict its future. And the story of its evolution is right there before our eyes. When we look up at the night sky we’re looking at the entire history of the universe: a record of its deep history.
The only problem is that the ‘single, complex and confusing snapshot’ we see when we look into the heavens is like ‘taking all the words in a novel, jumbling them up and sticking them on a single page.’ In this episode, Jim told how scientists have peered into this mystery in the last half-century and come up with some answers.
He began with Fred Hoyle who, in the 1950s, wanted to know how all the elements (oxygen, carbon, nitrogen, etc) that make up our world (including us), were formed from helium and hydrogen. Hoyle knew the answer must lie in nuclear fusion – when lighter elements fuse together to make more complex ones. Scientists already knew this happened in the heart of stars, where hydrogen fused to make helium. But how might helium fuse to make heavier elements?
Fred Hoyle worked out how carbon was made from helium atoms. If not for what became known as the Hoyle resonance we wouldn’t exist, for we are stardust, as Joni once sang. Jim gave us a simple demonstration of this as he walked through woodland (carbon – see?). At the same time he explained a key stepping stone in Hoyle’s calculations: the Hertzsprung-Russell diagram which astronomers use to classify stars by size and brightness. Jim made one of these out of rocks and coloured balls he just happened to have in his rucksack. Before Hoyle, scientists could see the patterns – but not what they meant.
Hoyle realised that in their lifetime all stars follow a path around the groups represented in the diagram – from the main sequence (like our sun) to the Giants, and then finally the White Dwarfs. This was the key to understanding the beginning – and also the end – of the universe. Hoyle’s conclusion was that, over an unimaginable length of time, stars would use up all the hydrogen and helium in the universe. Stars would die, but no new ones could form. The universe would go dark: the end of light and life. In the paper that set out his conclusions, Hoyle quoted King Lear:
It is the stars, The stars above us, govern our conditions.
Now Jim backtracked from Hoyle in the 1950s to 1917, when a brilliant but little-known astronomer Vesto Slipher managed to work out from an almost unintelligible dirty smudge of a spectrum reading from Andromeda (the best that a telescope could provide at the time) that Andromeda is heading towards us (its spectrum was in the blueshift rather than redshift range).
How can this be? Since confirmation of the Big Bang theory, our understanding has been that since the Bang the universe has been expanding and most galaxies are actually heading away from each other. The only explanation for Slipher’s finding was that gravity was overwhelming the force of that expansion. If that’s the case, the universe will end ‘with a big crunch’.
So we have two scenarios for the end of the universe: endless expansion or the big crunch. Which one is correct depends on how much matter there is in the entire universe.
It was another marginalised woman who supplied a key to answering that question. Beatrice Tinsley, said Jim, was an excellent astrophysicist whose 1966 PhD thesis questioned the whole basis of the calculations on which the expansion theory rested. Tinsley’s PhD research changed the standard method for determining distances to far-away galaxies. This was significant in determining the size of the universe and its rate of expansion. But, despite being awarded her PHD, as a married woman Tinsley was excluded from permanent work.
So, after Tinsley’s work it was back to drawing board. The only way forward, it seemed, was to count everything in the universe! Scientists overcame this seemingly insoluble problem by measuring the amount of stuff in one corner of the universe and then averaging it out.
But there was another problematic issue lurking in the background. In the 1930s an eccentric Swiss astronomer had proposed the idea of dark matter. He had suggested the presence of this invisible stuff – invisible because it doesn’t reflect light – present because his investigations into gravitational effects on galaxies demonstrated something was there, and having an effect.
His idea was ignored, largely because of his eccentric and aggressive attitude to the rest of his profession. He once said, ‘Astronomers are spherical bastards. No matter how you look at them they are just bastards.’ So Zwicky’s major contribution to astronomy remained virtually unknown.
It was at this point that Jim introduced us to gravitational lensing – a strange effect that had been predicted by Einstein who suggested that matter warped space, bending light and giving rise to visual tricks like the one that led scientists at the Jodrell Bank telescope in 1979 to think they had detected two identical quasars in the same patch of space – when in fact it was just one. After four decades, this was confirmation of Zwicky’s theory of dark matter.
Further observations revealed that the amount of dark matter in the universe far exceeds the amount of visible matter: in fact it probably accounts for around five-sixths of the matter in the universe.
Then, in the 1990s, came ‘a shocking new discovery that threw physics into crisis’. At the GTC telescope cluster in La Palma, Jim described work that measured the redshifts of supernovae at greater distances – thus further back in time. He joined scientists there as they replicated the 1990s research by measuring the redshift of a supernova – an exploding star 8 billion light years away. Their work reveals that, instead of gravity slowing down the expansion of the universe as most astrophysicists assumed, the universe is expanding evermore quickly.
Their observations detected smaller redshifts from distant galaxies – meaning that the universe was expanding more slowly in the past. But, since 6 or 7 billion years ago it’s been speeding up. Which suggests that, rather than ending in the ‘big crunch’, the universe will eventually fly apart, leaving galaxies, or (if they are ripped apart) individual stars ‘all alone in a black emptiness’.
The question challenging astrophysicists now is: what is causing this accelerating expansion? Cue: dark energy!
Current estimates suggest that dark energy (i.e. the stuff we don’t know anything about) makes up 70% of the universe. Jim concluded that the fate of the universe has become much more than just an academic question. The appearance of dark energy challenges the fundamentals of physics, and so could have profound implications for how we understand our world.
At the end of all this I’m left marvelling at the brilliance of the scientists whose intuitive leaps and meticulous investigations and calculations brought us to our present understanding of the cosmos. I marvel, too, at the technology they use which enables us to see into the farthest reaches of space and back almost to the beginning of time.
At the same time it occurs to me that, although we know so much more, each time we push back the frontier of our knowledge new mysteries unfold. Perhaps we are no closer to the ultimate mystery, the unknowable. Paradoxically it’s clear now that the answers to the future of the universe lie in its past – in those first milliseconds when everything in the entire universe was compressed to a microscopic size.
Today we weave theories based on rigorous scientific investigation. Our ancestors wove cosmological theories based on imagination and belief. Like modern science, the creation myths found in all cultures all share a common feature: they describe the ordering of the cosmos from a state of chaos, and represent the earliest attempts to explain in symbolic narratives of the beginning of the world some of the most profound questions about the nature and origin of the universe.
Judaism, Christianity and Islam all share the same six-stage narrative of the creation that is expounded in Genesis 1. But, further back in human history and in all cultures, there have been stories that told of how the world was created from nothing.
Here’s a remarkable example, from one of the oldest extant texts in any Indo-European language. The Rigveda is an ancient Indian collection of Vedic Sanskrit hymns. It is one of the four canonical sacred texts of Hinduism known as the Vedas. It was probably composed in the north-western region of the Indian subcontinent between 1500 and 1200 BC. It contains this: the Creation Hymn of Rig Veda.
There was neither non-existence nor existence then.
There was neither the realm of space nor the sky which is beyond.
In whose protection?
Was there water, bottlomlessly deep?
There was neither death nor immortality then.
There was no distinguishing sign of night nor of day.
That One breathed, windless, by its own impulse.
Other than that there was nothing beyond.
Darkness was hidden by darkness in the beginning,
with no distinguishing sign, all this was water.
The life force that was covered with emptiness,
that One arose through the power of heat.
Desire came upon that One in the beginning,
that was the first seed of mind.
Poets seeking in their heart with wisdom
found the bond of existence and non-existence.
Their cord was extended across.
Was there below?
Was there above?
There were seed-placers, there were powers.
There was impulse beneath, there was giving forth above.
Who really knows?
Who will here proclaim it?
Whence was it produced?
Whence is this creation?
The gods came afterwards, with the creation of this universe.
Who then knows whence it has arisen?
Whence this creation has arisen
– perhaps it formed itself, or perhaps it did not –
the One who looks down on it,
in the highest heaven, only He knows
or perhaps He does not know.
– Translation by Wendy Doniger O’Flaherty
In Maps of Time: An Introduction to Big History (2004), the historian David Christian summarised issues common to multiple creation myths:
Each beginning seems to presuppose an earlier beginning. […] Instead of meeting a single starting point, we encounter an infinity of them, each of which poses the same problem. […] There are no entirely satisfactory solutions to this dilemma. What we have to find is not a solution but some way of dealing with the mystery. […] And we have to do so using words. The words we reach for, from God to gravity, are inadequate to the task. So we have to use language poetically or symbolically; and such language, whether used by a scientist, a poet, or a shaman, can easily be misunderstood.
Christian’s point – how we reach for poetic or symbolic language to express the mystery of the creation of matter out of chaos or a vast emptiness, and our bewildered sense that there must be places beyond the border where things end, and time before time began – is perfectly expressed in one of William Blake’s best-known, but misunderstood images.
Blake’s image of a bearded, godlike figure, holding a compass against the chaos of the forming universe, is repeatedly misinterpreted. It’s clear from Blake’s own words that the figure is not the God of the Bible, but Urizen, one of Blake’s own mythical creations. For Blake, Urizen – a play on ‘your reason’ – symbolized the imposition of the rational methods of mathematics on chaos. But for Blake this was not an act of benevolence, but a cruel and unwanted restraint on the otherwise free forces of the imagination.
The art historian (and Soviet spy) Anthony Blunt said that, for Blake, Urizen’s role was to ‘crush man’s sense of the infinite, and to shut him up within the narrow wall of his five senses.’ The image therefore expresses Blake’s deep revulsion against facts established by weight, measurement or number, rather than the truths perceived through the imagination.
Preparing for the Big Emptiness
Smudges of moon in the morning
fingerprints of the moon eaters.
A new core gathers for the evening
to be plucked and crumbled by other hands
Is it your core?
Are they your hands?
Sometimes there is blue in between
Sometimes there is no one
You must prepare for the big
emptiness to come
It has come
When it comes
You must spread yourself thinly
To fill what can’t be filled
It has come
Unlike the moon you must do it
by Kapka Kassabova