|Piper Verlag, October 2009, 288 pp.
Have you ever wished that you could turn the clock back and take a different turning in your life? On 7 November 2000 the American Vice President Al Gore could have made good use of such an opportunity. This is on the day of the presidential election, when the night turns into a thriller. First the television declares Al Gore the winner, then suddenly his challenger George W Bush is leading in the decisive state of Florida. At 2.30 a.m. Gore makes a fateful error. He telephones Bush, congratulates him on his victory and has himself driven home through the rain. But in the course of the night Bush’s lead in Florida shrinks again. At 3.45 a.m. Gore picks up the telephone again. ‘Things have changed’, he says to Bush.
Too late. The picture of the loser is everywhere. There follows a week of stalemate and then the constitutional court calls a halt to recounting the Florida votes. The 43rd President of the United States is George W Bush, not Albert A Gore.
A few months after the election, when Bush has already been in post for some time, something strange happens. In the leading journal for physicists, Physical Review, an extremely curious article by Professor Alexander Vilenkin appears. At first glance the text seems quite normal. For ten pages the scientist holds forth about the structure of the universe soberly and in the usual terms. But in the final section there comes suddenly: ‘Some readers will be pleased to know that there are infinitely many O-regions where Al Gore is President and - yes - Elvis is still alive.’
The writer adds something more. Addressing his readers, he writes: ‘Whenever a thought crosses your mind that some terrible calamity might have happened, you can be assured that it has happened in some of the regions [of the multiverse]. If you nearly escaped an accident, then you were not so lucky in some of the regions with the same prior history.’
Has a physicist’s imagination got the better of him? Has Alexander Vilenkin been reading too much bad science fiction? On the contrary, Vilenkin ranks as the foremost thinker in his field: the science of the universe. And speculations which sound like science fiction are treated seriously these days. No-one should be surprised any more when an article about doubles and parallel
universes appears in a leading physics journal. Perhaps the only astonishing thing is why physicists have only just taken this up.
An irreverent idea is conquering science and the subject of this book is that idea and its consequences. The basic theme can be put in one sentence and is as simple as it is incredible: our universe is only one of many and everyone has doubles in other universes.
If this idea seems rather wild to you it was the same for us when we began researching for an article on the ‘multi-verse’. Then it got exciting. First we thought parallel worlds were a kind of intellectual tomfoolery on the part of eccentric physicists but it soon became clear how much the theme is haunting scientists and non-scientists alike and how vehemently the idea is being fought by its opponents. Everyone takes sides about the multiverse.
In fact today an increasing number of physicists believe that there is not just one universe but several and that each one provides an incalculable multiplicity of alien worlds, comparable to a boundless sea with countless inhabited and uninhabited islands. Hollywood directors and writers have exhausted this scenario; philosophers and theologians are in despair over it. But now the theory of parallel universes is also being increasingly advocated in earnest by natural scientists. Very possibly they will be proved right in the end. Then humankind will be faced with the most radical change to its self-image since the Copernican revolution. In the sixteenth century Nicolas Copernicus put an end to the centuries-old concept that the earth lay at the centre of the universe. Today scientists are planning the next major step: instead of one single universe they are postulating an infinite multiplicity of universes: the ‘multiverse’, ‘megaverse’ or ’pluriverse’. This is what they call the totality of all universes. There is nothing more enormous.
‘I would bet that at the turn of the twenty-second century, philosophers and physicists will look back to the present as a time when the twentieth-century concept of the universe gave way to a megaverse, populating a Landscape of mind-boggling proportions,” prophesies the physicist Leonard Susskind.
Are all the physicists off their heads? The theory of the multiverse has sparked off a violent controversy, because it is as yet in no way clear whether the theory can ever be proved. Nevertheless there is a lot at stake – not just for science but for every one of us.
This book is a live report on a scientific revolution. It helps one navigate through the range of ideas about the multiverse. We show what writers, film directors and philosophers have thought of the idea of many different worlds, discuss the dangers for science of the speculative conception of the multiverse and fathom the consequences, if the multiverse were actually to exist: what is the meaning of life in a multiverse with an infinite number of doubles? If there still room for God? Will we ever meet our doubles? And on the practical level, must I recycle my rubbish if my double in the other world just throws everything into the same bin? Must I buy a rail ticket, while my double is a regular fare-dodger?
On the one hand the multiverse seems too crazy to be true; on the other, five hundred years ago people also thought the idea crazy that the earth should move around the sun while at the same time turning on its own axis. Two hundred years later this concept of the world is universally accepted and today the way the earth turns is simply fact.
So what has to happen to make what seems a crazy idea become a majority scientific opinion and eventually a generally accepted view of the world? This is the subject of the first part of this book, in which we recapitulate the Copernican revolution, the modern creation history of the big bang and today’s faulty world view of cosmology and make our first acquaintance with the multiverse. Anyone who wants to take a short cut should read chapter four and the second part of the book, where we examine why the theory of the multiverse is so popular among today’s experts and go in search of our doubles in parallel universes. In fact as a precautionary measure physicists have already worked out at what distance we can meet our nearest doubles. We accompany astronomers on the search for intelligent life and throw light on the increasingly desperate search for a world formula. And we enquire into the meaning of life in the multiverse. An American philosopher called the multiverse the ‘'the last resort for the desperate atheist’. But there is room for Christians, too, in the many worlds, as the final chapter shows.
This book is written by two authors from the same world but they hold opposing opinions. They have researched for a year, pored over books and held innumerable conversations with sceptics and advocates of the mutliverse. During this period Tobias Hürter embraced the idea that the world in which we live may possibly consist of many worlds. Max Rauner found the theory of
the multiverse increasingly crazy. The discussions were very enjoyable. This book is not intended to convert anyone to the multiverse but to convince the reader that it is worthwhile thinking further than one can see. Clear your head to be ready for the greatest of all worlds.
Tobias Hürter and Max Rauner
It is actually possible that God has created millions of worlds.
Immanuel Kant, Thoughts on the true value of living forces, 1746
The coffin was well preserved and lay 32 cm under the marble floor. It was made of iron and lined with cloth. The skull lay on a silk cushion filled with straw; the skeleton was delicate. A woman of about twenty, the archaeologists estimated. It was of no interest and they continued digging.
In the second grave they came across the skeleton of a man of about fifty, whose facial bones were crushed; the third grave they damaged as they dug it out; in the fourth and fifth graves again just men of between forty and fifty. So it went on for months. Like boars digging for truffles the archaeologists dug through Frombork Cathedral on the Baltic Coast of Poland. In the thirteenth grave, by the altar of the Holy Cross, they found the skull of a man who must have been between sixty and seventy when he died. Were these the bones they had sought so long? In November 2008 DNA comparison with a hair found in a book belonging to the man they were looking for brought certainty: this was the head of Nicolas Copernicus, canon of Frombork and amateur astronomer, who died in 1543 and was responsible for the greatest revolution within living memory.
‘This is a great event for Frombork,’ said Bishop Jacek Jezierski, who had commissioned the search for Copernicus’s mortal remains. In the spring of 2010 the skeleton will be formally buried in a ‘beautiful coffin’, as the bishop promises. The whole world will join in.
What a career: in his lifetime a nonentity, shortly after his death a heretic, today a hero.
Copernicus overthrew a view of the world which had prevailed for two thousand years and banished man from the hub of the universe. Since ancient times people had believed that the earth stood in the centre of the world and that the sun moved around it like the other planets. A false conclusion, maintained Copernicus, in actual fact the sun stood at the centre and the earth revolved around it on a course between Venus and Mars. The changes from day to night were caused by the turning of the earth. As his work De Revolutionibus Orbium Coelestium about this sun-centred world view is being printed in Nuremberg, the sixty-nine year old Copernicus has a heart attack in Frombork. A few months later he is dead but his ideas are in the public domain. The church mounts its resistance. In vain.
Copernicus’s revolutionary theory shattered people’s understanding of themselves. At some point the church gave way. Not only Copernicus will now be formally re-interred but also Galileo Galilei, who was sentenced to house arrest in his lifetime and only 300 years later has received the highest recognition from his former opponents. In 2009, the international year of astronomy, the Vatican honoured him for the first time with a Mass and in his Christmas message Pope Benedict XVI expressly praised Galilei, adding that natural laws were ‘a good reason to remember the Lord’s creation with gratitude’.
That sounds urbane and salutary – but the biologists are already a step ahead. While the church rewrites its past, they are planning a coup which could put the Copernican revolution in the shade, by saying that our universe is just one among many and every human being has doubles in other universes. This is anyhow what serious physicists maintain. They are doing their research in the best universities in the world; they publish in prestigious specialist journals; they belong to the leading elite of theoretical physics.
And they mean it in all seriousness.
500 years after Copernicus the signs are once more pointing towards revolution: the universe is being called a multiverse – sometimes even a pluriverse or megaverse. There is not just one universe but an infinite number. We live in one of them, in one niche in a multiplied cosmos. Every imaginable world exists in reality; every possible history is being played out somewhere. The Copernican revolution is being carried to its conclusion.
If Copernicus’s about-turn was an insult, as Sigmund Freud dubbed it, then the multiverse is an affront. Physics professor Alexander Vilenkin of Tufts University in Boston, Mass. described it in all modesty: ‘Degrading human mankind to total cosmic insignificance is the last step in our departure from the center of the universe’. The fulfilment of the Copernican revolution is a combined project and Vilenkin, a small, quiet man of about 60, is one of its guiding intellectual forces.
The church used to have a monopoly on the creation story, but then came universe scholars like Copernicus and Newton and today there are physicists like Vilenkin to explain the world to us. How did it begin? Where do we come from? Where are we going? In 1915 Albert Einstein formulated his General Theory of Relativity from which physicists calculate black holes, the expansion of the cosmos and the births of stars and galaxies. Ten years later came the quantum theory which described the microworld of the atom. Around 1950 physicists developed the big bang theory, according to which all the matter and energy in the universe was once concentrated in a single hot, dense point from which it then flew apart.
Vilenkin is accustomed to leaving the beaten track. When he was studying physics in the sixties the big bang theory was becoming increasingly popular and the Soviet Union increasingly unappealing. As a student Vilenkin refused to be a KGB informer. They put him on their black list and the educational professions were closed to him. Vilenkin was send to work as a nightwatchman at the zoo in Charkov, a town in northern Ukraine. He was supposed to guard a liquor kiosk. He had a gun but did not know how to use it. He was sorry for the animals behind bars. During the nights when he was not drunk, he brooded on the universe. In 1976, at the age of 26, he was allowed to emigrate and two years later joined Tufts University as a professor. There he conceived the irreverent idea of a quantity of worlds.
When Vilenkin and his Russian colleague Andrei Linde calculated the force which had blown out the universe after the big bang, they both came to the conclusion that the blast must persist beyond our universe. However that would mean that new universes were constantly forming like bubbles in a foam bath. For every bubble a big bang and so a new universe. And because there is such an unimaginable quantity of universes, in many of them there are living creatures, people and even our doubles.
‘The big bang that we had in our part of the universe was not a unique event as we thought before, but there were multiple bangs,’ says Vilenkin, ‘These bangs create regions, some of them similar to ours, some of them with different properties.’
In the new picture of the cosmos our home universe is as minute as a grain of sand in the desert. Some of the other universes are barren and empty; others are ruled by outlandish natural laws or have particles streaming through them at more than the speed of light. In many fantastic shadowy creatures flit through extra spatial dimensions. Many universes are like our own – except that John F Kennedy is still alive and married to Marilyn Monroe. In others, according to Vilenkin, there are identical earths to ours, where dinosaurs have survived and people drive huge cars. In others again Nazi Germany did not lose the war but gained world domination – ‘Unfortunately anything which is not forbidden by the laws of physics.,’ says Vilenkin.
Previously Vilenkin’s lectures were often met with an embarrassed silence. Today the audience claps. Admittedly the idea of many worlds is incredible but 500 years ago Copernicus’s concept of the world was also incredible. 150 years later it had become an accepted fact.
The theory of the multiverse could solve one of the greatest riddles of mankind: our existence. Since the big bang the universe seems to have been cut out to produce stars, galaxies, planets and, one day, human beings. For if natural constants like the charge of the electron or gravitational force had been just a little different, atoms or stars could never have come into being after the big bang. Is our existence a lucky chance? Or does it follow inexorably from the laws of nature? Einstein put it like this: Did God have a choice when he created our universe? To Einstein God was just a rhetorical trick. He was not looking for God but for an all-embracing theory which would precisely define our, and only our, universe with all its characteristics. He did not find that theory, but physicists are still dreaming about it today.
Leonard Susskind, born in 1940, professor of physics at Stanford University in California and another exponent of the world like Vilenkin and Linde is one of those who tried to realise that dream. Susskind set out to find an all-embracing theory which would describe both the big bang and the nano-world, a synthesis of the theory of relativity and the quantum theory – in fact, a world formula. One day, he hoped, one would be able to calculate all the laws and constants of nature from one single mathematical formula. The structure of the universe would then follow logically from this universal law.
In the eighties Susskind believed he knew how to reach a world formula through the so-called string theory, which he himself had helped to formulate. It then became apparent, however, that the string theory did not provide one single world formula, but incalculable numbers of formulae.
In 2005 it dawned on Susskind that this was actually the point: there can be no one, unequivocal, world formula because there is not just one world. Every interpretation of the string theory applies to one actual universe – to its own natural laws and natural constants, its own history and its own future. In some universes the force of gravity is so strong that these worlds will implode on themselves again within a short period of time, while others will exist for ever but remain empty, and others again will produce stars, but no planets like the earth. And our own universe had exactly the right natural laws to produce, fourteen milliard years after the big bang, intelligent humans who would rack their brains over the origin of the universe. Our world is only one island able to sustain life in the ocean of worlds.
The age-old fundamental question – why the world is the way it is – is answered quite simply in the multiverse: our world is just one of countless other worlds which in part are completely differently formed and in part like ours. Our universe is thus no exceptional case, but statistically normal – as normal as throwing a six in lotto if there are enough players. For the winner it may seem a miracle but for everyone else it comes as no surprise.
In the multiverse everything is possible and everything is normal.
Susskind’s scenario strikingly resembled Alexander Vilenkin’s bubble multiverse. He changed sides and now believes in the multiverse instead of the world formula. The multiverse is infinitely varied – sometimes simple, sometimes complicated. The theory of the multiverse will win the day, proclaims Susskind, ‘Gradually, cosmologists and physicists are coming to see our ten billion light-years as an infinitesimal pocket of a stupendous megaverse.’
Leonard Susskind and Alexander Vilenkin come from different fields in physics; one researches the big bang, the other the string theory. Both ways lead them to the multiverse. And even colleagues from quantum physics have long been arguing over the possibility that not one but many worlds exist. Their paths cross – that is one reason why the theory is discussed so vehemently at the moment; the other is that the theory of the multiverse borders on science fiction and for many researchers that runs counter to their professional integrity.
After Copernicus had postulated the heliocentric image of the world it was only a question of time before Galilei looked at the sky through a telescope and found important evidence for the
Copernican theory. There will probably never be such direct evidence for the multiverse but that is not a necessary prerequisite for putting one’s trust in a theory. Natural philosophers were speculating about the existence of atoms two thousand years ago, but only in the 19th century didindirect proof finally arrive and it was 1955 before a specialist microscope provided an image of an individual atom for the first time. Another example is Einstein’s theory of relativity. Today it is generally accepted that physicists can even use it to assess black holes, even though no astronomer has ever seen one (not even in the LHC at CERN near Geneva). Finally the theory of relativity – in contrast to the multiverse theory – has stood the test of countless experiments. But even the theory of the multiverse must at some point be measured against reality. If it provides practical explanations for our own universe, it might be possible to take its statements about parallel universes seriously. If the multiverse remains pure speculation, physics would be at an end – or possibly only just starting up. For this is how science began 2500 years ago in ancient Greece: with philosophising over nature.
Several things have to come together if a new scientific theory is to become the world view for an epoch. Thomas Kuhn, a sociologist who died recently, has investigated upheavals of this kind and the Copernican revolution was his favourite example, from which in the seventies he developed the concept of changing paradigms, which has since become well-known. Kuhn’s thesis was that scientific progress is no straightforward process, no steady assembling and expanding of knowledge. It proceeds in leaps and bounds. Quiet phases of ‘normal science’ are followed by violent crises and then scientific revolutions in which a new paradigm takes over from the old one. When Nicolas Copernicus was studying in Cracow, Christopher Columbus was sailing towards unknown continents. Global geography had to be rewritten. In Wittenberg Luther was nailing his theses to the door of the castle church. Book printing was invented. The world was ready for a paradigm change. Maybe it is ready again today. The world of the 21st century is globalised, confusing, pluralistic. The multiverse would fit in with it well. A world image for postmodernism! But it will be no easier for it to be accepted than it was for Copernicus’s view. His revolution lasted a good 150 years, from his death to the publication of Newton’s theory of gravity in 1687. Why should things go any faster this time? No-one will easily accept the idea of living in innumerable parallel universes and so far the thesis that there are other universes out there is only a suspicion which is gaining ground. Only if it at least stands empirical tests on some points will we see a continuation of the Copernican revolution. But there is already an indication of a parallel to the situation five hundred years ago: Copernicus did not invent the heliocentric image of the world but only helped it to come into its own; other people had thought of it before him. It is the same with the multiverse. Even the concept of many worlds is deeply rooted in spiritual history. In the first century BC the Roman poet Lucretius prophesied that ‘sky, earth and sea, even sun and moon, exist in countless numbers’. In the 13th century clerics and scholars debated the question of whether a Christian God could have created infinite numbers of worlds. In the 17th century the philosopher Gottfried Wilhelm Leibnitz believed that with our world God had brought into being ‘the best of all possible worlds’. Immanuel Kant mused about island worlds far out in the cosmos. Ideas of multiverses are to be found today in the works of famous writers like Vladimir Nabokov and Jorge Luis Borges, and under the name Alternate History a whole literary genre is concerned with the question of how history would have unfolded, if … In the multiverse Alternate History is no longer fiction but part of the science of history. People have been thinking about alien worlds with shudder and longing since time immemorial. Our era could be the one in which such fantasy is demonstrated to be reality. The multiverse could become the world image of the 21th century. Whether it will be established as a new paradigm is however not at all certain as yet. Critics recognise that the greatest weakness of the vision of the multiverse lies in its very immensity and the fact that it is nothing but speculation – a castle in the air which will collapse. ‘It’s taking us down a dangerous path’, says physics professor Paul Steinhardt of Princeton University about the idea of the multiverse. The theory is too speculative, ‘This is no longer interesting science. Its just an intellectual activity.’ Anyone who accepts the multiverse sacrifices noble ideals of science, above all the requirement that it be verifiable by experiment, for parallel universes are by their very nature inaccessible to direct observation. Light rays from one universe cannot penetrate another. Can a natural scientist nevertheless talk about them? The question divides physicists. Some say that it is a betrayal of the eternal principle of empirical research while others see in it a liberation of natural science, an
opening for so far unanswerable questions. The positions are drawn up. Let battle commence.
© Piper Verlag GmbH, München 2009
English sample translation by Anne Wyburd